With the DFT-D3 density functional dispersion correction, the effective core pseudopotential basis set of LANL2DZ was applied to metallic Ni atoms. The reaction energy barriers of NiNx catalysts are different from the co-adsorption structure during the catalytic hydrogenation of graphene-NiNx . The calculated results showed that the energy barrier and selectivity of graphene-NiN4 for ethylene production were 25.24 kcal/mol and 26.35 kcal/mol, respectively. The low energy barrier and high activity characteristics showed excellent catalytic performance of the catalyst. Therefore, graphene-NiN4 provides an idea for the direction of catalytic hydrogenation.In this study, using the application of density functional theory, the mechanism of graphene-NiN In modern industry, ethylene in petrochemical products is one of the mainstream industrial raw materials and plays a critical role in the national economy. Ethylene is also a crucial industrial source and fundamental synthetic monomer . After s2 and employed STEM (scanning transmission electron microscopy), FTIR , and other means to examine the catalysts’ catalytic performance. The results reveal that the catalyst is capable of the selective hydrogenation of acetylene in an ethylene-rich environment under mild conditions. Among them, 100% ethylene selectivity was observed on CuPd0.08/TiO2 catalyst. Choudhary et al. [2, Pd/TiO2, and Au-Pd/TiO2 catalyst. The results revealed that the Au/TiO2 catalyst (average particle size: 4.6 nm) synthesized using reduction-oxidation was discovered to exhibit high selectivity for the synthesis of ethylene through temperature programming, but the acetylene conversion activity and catalyst stability were not satisfactory. Noble metal catalysts are expensive and rare. Thus, researchers turned their attention to the field of non-precious metal catalysts, such as Ni, Cu, Ni, Zn, etc. Zhuo et al. [1/SV-G, and M1/DV-G  using density functional theory (DFT). The results reveal that among them, Pt1/DV-G and Ni1/DV-G are the suitable catalysts for acetylene hydrogenation, and Ni1/DV-G shows higher selectivity for the semi-hydrogenation products of acetylene. Riley et al. [11 nanoclusters were selected as catalysts, and it was discovered that they have good activity and selectivity for acetylene hydrogenation. Researchers decided to replace different supports to enhance the reactivity and selectivity of non-noble metal catalysts.There is a lot of research in the field of catalytic acetylene hydrogenation on noble metal and non-noble metal catalysts at present. Ball et al.  modifiedy et al.  performeo et al.  examinedy et al.  demonstrx as active centers have recently been reported [x  in various reactions [x  series catalysts. The aim of this paper is to investigate the reaction pathway of catalytic hydrogenation of acetylene based on the reaction mechanism of acetylene hydrogenation. The reactivity and selectivity were used to find the excellent catalysts to promote the hydrogenation reaction. In conclusion, this study broadens the research direction of nickel-based catalysts and also provides some insights into the research in the field of non-precious metals.Graphene research has shown a linear growth tendency since it reached people’s field of vision . Graphenreported ,23,24,25eactions ,33,34,352H2 and H2 on graphene-NiNx catalysts were calculated, and the adsorption energies (Eads) and co-adsorption energies (Eco-ads) were defined as in the following:The DFT calculation process employed in this investigation was completed in the Guassian09 software package . Based oads is single adsorption energy of the reactant molecules on the catalyst. Eco-ads are co-adsorption energies. Eads-state is the whole energy of the C2H2/H2 and NiNx, Eco-ads-state is the overall energy of the system. While 2H2 and H2 molecules and NiNx, respectively.Ex catalyst and reactants C2H2 and H2 molecules are shown in x configurations all have a planar structure, while the C2H2 molecule is a linear structure. According to the various doping amounts of N atoms, graphene-NiNx can be classified into four geometric configurations: graphene-NiN1, graphene-NiN2, graphene-NiN3, and graphene-NiN4, each of which has only one stable configuration. However, 2 (A), graphene-NiN2 (B), and graphene-NiN2 (C) according to the doping N atoms’ arrangement. 2 (A) structure, two doped N atoms are in the ortho position in the same five-membered ring; in the graphene-NiN2 (B) structure, there are also two doped N atoms. The atoms are located in different five-membered rings on opposite sides of the Ni atom; the two doped N atoms in the graphene-NiN2 (C) structure are in the ortho position in the same six-membered ring. For this purpose, the average Ni-N and Ni-C bond lengths of graphene-NiNx  were further calculated in this study, and the calculation results are shown in x catalyst, the average Ni-N bond length for doping four N atoms is 1.961 Å, which is the maximum in the catalyst. In the graphene-NiN1 catalyst, Ni-C is 1.880 Å, which is the maximum data for the average bond length of Ni-C.In this study, the optimal graphene-NiNx  catalysts described on the molecular van der Waals surface (electron density 0.001). The enrichment of positive and negative charges causes a color shift toward blue-red. The higher the shift to blue, the higher the charge density of positive charges, and the higher the shift to red, the higher the charge density of negative charges. As shown in x  were plotted [1, the p orbital of C atom and N atom make the main contribution and the secondary contribution, respectively; in the HOMO orbital, the LUMO orbital makes the main contribution is the p orbital of C atom, while the Ni atom makes a greater contribution in an empty orbital. The HOMO orbital contributions of graphene-NiN3 and graphene-NiN4 have similarities with those of graphene-NiN1, and it is evident that the Ni atoms in the LUMO orbitals contribute less to the frontline orbitals. For graphene-NiN2 catalysts doped with two N atoms, the p orbital of the C atom in graphene-NiN2 (A) makes the primary contributions to both LUMO and HOMO orbital, the p orbital of the N atom is second, and the Ni atom has more contributions. In graphene-NiN2 (B) and graphene-NiN2 (C), the p orbital of C makes the main contribution to the HOMO orbital, followed by the d orbital of the Ni atom, and finally the p orbital of the N atom. Among the LUMO orbitals, the p orbital of the C atom is the main contributor, and the p orbital of the N atom is the secondary contributor. We speculate that Ni atoms and the C and N atoms coupled to Ni atoms are the catalyst’s potential active sites.To deeply understand the catalysts’ properties, the total density of states and the partial density of states of the six catalysts of graphene-NiN plotted  and adde2 and C2H2 molecules on the top of the Ni atom, and on the C and N atoms around the Ni atom, to conduct single adsorption behavior, and we obtain the single adsorption structure with the lowest energy. x  catalyst. The figure shows that the NiNx series catalysts tend to be adsorbed on the Ni atoms and the C and N atoms are coupled around the Ni atoms. The Ni atom is slightly tilted upwards when the graphene-NiN4 catalyst is adsorbing acetylene. x  catalysts through further calculation. The C2H2 of the six catalysts are all larger than the H2 adsorption energy, which proves that during the adsorption, C2H2 is more likely to be preferentially adsorbed, and then H2 is adsorbed to form a co-adsorption structure. Furthermore, the single adsorption energies of both C2H2 and H2 are smaller than the co-adsorption energies ensuring that the reaction is performed within a reasonable range.In the whole reaction, adsorption is the most crucial step. We place the reactants Hx  series catalyst for acetylene hydrogenation, this paper draws a detailed reaction path and the corresponding energy diagram. Graphene-NiN1, graphene-NiN2 (A), graphene-NiN2 (B), graphene-NiN2 (C), graphene-NiN3, and graphene-NiN4 catalysts were investigated for activity and selectivity, respectively.In order to fully explore the reaction process of NiN1 acetylene from acetylene to ethane, while 1, the reactants C2H2 and H2 molecules were adsorbed roughly above the catalyst, almost parallel to the graphene-NiN1 substrate. First, the reaction pathway starts with co-adsorption (R) with co-adsorption energy of −8.91 kcal/mol. To obtain intermediate IM1, co-adsorption undergoes transition state TS1 with an imaginary frequency of −1831.70 cm−1. In TS1, the C2H2 molecule was deformed, the two H atoms gradually migrated above the Ni atom, and the H1 atom vibrated to the C1 atom to obtain the intermediate IM1. The reaction energy barrier of this process is 28.68 kcal/mol, which is the rate-controlling step for the hydrogenation of acetylene to ethylene. Secondly, the H2 atom coupled to the C3 atom must undergo two transition states TS2 (imaginary frequency of −258.53 cm−1) and TS3 (−859.12 cm−1) to obtain the intermediate IM3 to produce ethylene. The H2 atom gradually vibrated to the C2 atom during the process from IM2 to TS3 and then to IM3, shortening the bond length from 2.297 Å to 1.082 Å and forming a bond. The energy barriers required for this process are 0.99 kcal/mol and 11.03 kcal/mol, respectively. The co-adsorption structure IM4 was optimized based on IM3 to realize the secondary hydrogenation of acetylene, with the co-adsorption energy of −79.43 kcal/mol. In the co-adsorption of ethylene and hydrogen, ethylene and H3 and H4 molecules are coplanar. Next, IM4 passes through the transition state TS4 with an imaginary frequency of −1652.41 cm−1 to obtain the intermediate IM5. The reaction energy barrier for the hydrogenation of ethylene to ethane is 28.38 kcal/mol, and this process is a rate-controlling step. In TS4, two H atoms and ethylene are placed in an oblique line in space. The H3 and H4 atoms migrate slowly to the top of the Ni atom, and the H3 atom stretches toward the C1 atom. The bond length between H3 and C1 is shortened from 1.557 Å to 1.094 Å between TS4 to IM5, and they are connected to form a bond. Finally, the H4 atom attached to C4 approaches the C2 atom and yields the product ethane (P) after passing through the transition state TS5 with an imaginary frequency of −1164.78 cm−1. The reaction energy barrier for this step is 6.67 kcal/mol. The bond length of H4 and C2 was shortened from 2.329 Å to 1.094 Å from IM5 to the product ethane and then formed a bond. IRC correctly confirmed the structure before and after the reaction path. It can be concluded from 1 catalysts. 1 has poor selectivity.2 (A) acetylene. First, the reaction pathway starts with co-adsorption (R) with co-adsorption energy of −6.26 kcal/mol. It is clear from the co-adsorption graph that the reactants C2H2 and H2 are in the same plane. The co-adsorption to the intermediate IM1 requires the transition state TS1 with an imaginary frequency of −1764.41 cm−1, and the reaction energy barrier of this process is 30.14 kcal/mol. This step is a rate-controlling step for the hydrogenation of acetylene to ethylene. The vibration analysis of TS1 also reveals that C2H2 is deformed, breaking the straight line. The H1 atom vibrates with the C1 atom. In IM1, H1 is bonded to C1, and H2 is bonded to C3 with bond lengths of 1.089 Å and 1.122 Å, respectively. Secondly, due to the long distance between H2 and C2 atoms, IM1 must pass through two transition states to obtain the intermediate ethylene. In TS2 and TS3, only one imaginary frequency is −120.53 cm−1 and −729.51 cm−1. IM1 only needs to pass through TS2 across an energy barrier of 0.92 kcal/mol to produce the intermediate IM2 that requires one inversion of the vinyl group. Crossing TS3 from IM2 to ethylene requires at least 6.24 kcal/mol of energy. Further ethylene hydrogenation from IM3 yields the co-adsorbed structure IM4, and co-adsorption energy was −64.96 kcal/mol. Next, the reaction undergoes a transition state TS4 with an imaginary frequency of −549.92 cm−1 to obtain the intermediate IM5 with a reaction energy barrier of 35.36 kcal/mol. The process of IM5→IM7 requires going through two transition states (TS5 and TS6) with imaginary frequencies of −678.69 cm−1 and −1560.44 cm−1, respectively. The process is separated into two steps of vibration of the H4 atom: the first step is to attack H4 from C3 to C4, and the second is the H4 atom’s vibration from C4 to N1 atom. The energy barriers required for the two steps are 18.57 kcal/mol and 23.42 kcal/mol. Finally, the reaction requires crossing the energy barrier of 55.38 kcal/mol to generate the product ethane (P) and obtain the transition state TS5 with an imaginary frequency of −1378.67 cm−1. This process is a rate-controlling step of the ethylene to ethane hydrogenation process. In TS7, the H4 atom vibrates toward the C2 atom and the bond length is rapidly shortened from 2.251 Å to 1.095 Å. The presence of corresponding reactants and intermediates at each transition state can be confirmed using IRC. 2 (A) catalysts. 2 (A) has certain activity and ethylene selectivity, and is an effective catalyst for acetylene hydrogenation.2 (B) catalysts in the catalytic acetylene hydrogenation process. First, the reaction pathway also starts from co-adsorption (R) with a co-adsorption energy of −6.01 kcal/mol. The process from R to IM1 requires at least 59.05 kcal/mol of energy and experiences TS1 with an imaginary frequency of −1686.31 cm−1. This step is a rate-controlled step for the hydrogenation of acetylene to ethylene. In TS1, the H2 molecule moves above the N atom, the H1 atom vibrates to the C1 atom. Since the H2 and C2 atoms are far apart, they go through five transition states to form ethylene. IM1 must undergo TS2 with an imaginary frequency of −1522.57 cm−1 and overcome the 30.1 kcal/mol energy barrier to produce intermediate IM2. Then, it crosses the energy barrier of 46.4 kcal/mol to reach the intermediate IM3, and there is a transition state TS3 (imaginary frequency is −300.22 cm−1) in this process. IM3 undergoes TS4 with an imaginary frequency of −1195.10 cm−1 and overcomes the energy barrier of 38.76 kcal/mol to produce intermediate IM4. To generate ethylene, intermediate IM4 also needs to experience TS5 and TS6 with imaginary frequencies of −546.91 cm−1 and −893.52 cm−1, respectively. The energy barriers required for these two processes are 6.16 kcal/mol and 44.11 kcal/mol, respectively. The H2 molecule was placed at a position near ethylene in the IM6 conformation, yielding the co-adsorption structure IM7 with a co-adsorption energy of −52.38 kcal/mol. Subsequently, The H3 and H4 atoms were activated and the bond length expanded to 1.516 Å at one point. The intermediate IM8 was formed through the transition state TS7 with an imaginary frequency of −1791.11 cm−1. This process is a rate-controlling step for the hydrogenation of ethylene to ethane, and the reaction energy barrier is 59.80 kcal/mol. The H4 atom connected to the N2 atom needs to undergo TS8 (imaginary frequency of −1529.63 cm−1) to obtain the intermediate IM9, and this process must overcome the energy of 13.23 kcal/mol. Next, IM9 needs to undergo two transition states of TS9 and TS10 to form the intermediate IM11, and there is only one imaginary frequency of −408.58 cm−1 and −1189.48 cm−1, respectively, and the corresponding energy barriers are 43.89 kcal/mol and 42.41 kcal/mol. Finally, the H4 atom attached to N1 only needs to pass through TS11 with an imaginary frequency of −2348.45 cm−1 and cross the energy barrier of 11.23 kcal/mol to generate the product ethane. In TS11, the bond length between H4 and C2 is abruptly reduced from 2.337 Å to 1.116 Å. After IRC calculation, it can be confirmed that there are corresponding reactants and intermediates in the transition states of the reaction. It can be concluded from 2 (B) catalysts. It can be seen from 2 (B) is not satisfactory.2 (C) acetylene. First, the reaction pathway starts with co-adsorption (R) and co-adsorption energy of −6.22 kcal/mol. The intermediate IM1 needs to cross over TS1 with an imaginary frequency of −1678.32 cm−1 to obtain the intermediate. The reaction energy barrier of this process is 57.16 kcal/mol. This step is a rate-controlled step for the hydrogenation of acetylene to ethylene. Differently from other catalysts, graphene-NiN2 (C) can form ethylene in only one step. In IM1, H1 forms a bond with C1, and H2 forms a bond with C2. The bond lengths are 1.087 Å and 1.086 Å, respectively. IM1 was further hydrogenated to form the most stable and optimized co-adsorption structure IM2, with co-adsorption energy of −51.89 kcal/mol. Secondly, IM2 overcomes the energy barrier of 59.30 kcal/mol and passes through TS2 to obtain the intermediate IM3, which is a rate-controlling step for the hydrogenation of ethylene to ethane. the H3 and H4 atoms continue to vibrate through the N1 atom to C1 in TS2, with an imaginary frequency of −1734.45 cm−1. Thirdly, IM3 undergoes a transition state TS3 with an imaginary frequency of −1598.17 cm−1 to form the intermediate IM4 with a reaction energy barrier of 15.66 kcal/mol. In TS3, the vibrational direction of the H4 atom is from N1 to N2 atom. Finally, IM4 undergoes transition state TS4 with an imaginary frequency of −2386.03 cm−1 to form the product ethane with a reaction energy barrier of 56.58 kcal/mol. IRC can confirm that the corresponding reactants and intermediates exist in the reaction’s transition states. 2 atoms are involved in the site of the graphene-NiN2(C) catalytic reaction. 2 (C) has unsatisfactory selectivity.3 acetylene continuous hydrogenation and the corresponding energy barrier of each step is as shown in 2H2 and H2 molecules are sterically parallel to the catalyst, and the co-adsorption energy is −54.83 kcal/mol. The transition state TS1 with an imaginary frequency of −1710.68 cm−1 is required from the co-adsorption to the intermediate IM1. In TS1, the linear C2H2 molecule is broken and changed. The H1 and H2 atoms move to the C2H2 molecule, and the H1 atom undergoes stretching vibration toward the C1 atom to form the intermediate IM1. In IM1, the reaction energy barrier of the process is 39.85 kcal/mol, which is the rate-controlling step for the hydrogenation of acetylene to ethylene, and the bond length of H1 and C1 atoms is 1.094 Å. Secondly, the H2 atom connected to the C3 atom needs to cross the two transition states of TS2 (imaginary frequency of −127.27 cm−1) and TS3 (−588.63 cm−1) to form the intermediate IM3 to form ethylene. The energy barriers required for these two processes are 0.60 kcal/mol and 3.80 kcal/mol, respectively. Further hydrogenation of acetylene starts from IM4 with a total adsorption energy of −100.52 kcal/mol. In IM4, ethylene and hydrogen molecules are directly above the graphene-NiN3 catalyst. Next, to form the intermediate IM5, the reaction undergoes a transition state TS4 with an imaginary frequency of −2173.29 cm−1, which is a rate-controlled step for the hydrogenation of ethylene to ethane with a reaction energy barrier of 39.04 kcal/mol. In TS4, the H3 and H4 atoms migrate to the vicinity of the C3 atom, and the H3 atom stretches toward the C1 atom. The reaction’s last step requires the transition state TS5 with an imaginary frequency of −263.51 cm−1 to form the product ethane (P). From IM5 to P, the reaction energy barrier for this step is 1.09 kcal/mol. IRC again confirmed the structures’ correctness before and after all transition states in the reaction path. It can be concluded from 3 catalysts. As can be seen from 3 is poor.The specific reaction path of graphene-NiN4 catalysts at each step in the catalytic acetylene hydrogenation process. First, the reaction pathway also starts from co-adsorption (R) with co-adsorption energy of −12.56 kcal/mol. The reactants are free C2H2 and H2 molecules, and their optimal adsorption sites are above the catalyst. The energy of at least 25.24 kcal/mol is required in the process of Co to IM1, which is a rate-controlling step for the hydrogenation of acetylene to ethylene. In the vibrational analysis of TS1, the H2 molecule moved above the Ni atom and below the acetylene molecule, and the H1 atom vibrated to the C1 atom, causing the shape of the C2H2 molecule to change, and only one imaginary frequency value was −1798.29 cm−1. Secondly, the H2 atom connected to the metal Ni atom needs to undergo TS2 (imaginary frequency of −1026.95 cm−1) to form the intermediate IM2 and must overcome the energy of 20.56 kcal/mol. In TS2, the H2 atom attacks the N1 atom, and the vinyl group undergoes a certain inversion. By the time of the intermediate IM2, the N1 atom forms a bond with the H2 atom with a bond length of 1.035 Å. Then, the H2 atom vibrates toward the C2 atom, the bond length between the H2 and C2 atoms is shortened sharply, and there is only an imaginary frequency with a value of −100.93 cm−1 that only needs to cross the energy barrier of 1.25 kcal/mol to form ethylene. Further hydrogenation starts from the co-adsorption structure IM4 with a co-adsorption energy of −59.90 kcal/mol. Subsequently, the H3 and H4 atoms were activated, the bond length was once expanded from 0.742 Å to 1.407 Å, and the intermediate IM5 was formed by the transition state TS4 with an imaginary frequency of −1798.29 cm−1. This process is a rate-controlling step for the hydrogenation of ethylene to ethane, and the reaction energy barrier is 51.59 kcal/mol. The last step is the process from IM5 to the product ethane (P), which requires at least 1.43 kcal/mol of energy and crosses the transition state TS5. The H4 atom connected to the N1 atom vibrates toward the C2 atom in the TS5 vibrational analysis, resulting in an associated imaginary frequency (−405.40 cm−1). The correct front and rear structures are connected to the transition states in the reaction after IRC calculations. In 4 catalysts. 4 has good reactivity and selectivity, and can be considered a potential catalyst for acetylene hydrogenation.1, graphene-NiN2 (A), graphene-NiN2 (B), graphene-NiN2 (C), graphene-NiN3, and graphene-NiN4 catalysts are detailed. To compare the catalytic performance of graphene-NiNx  in acetylene hydrogen, the reaction energy barrier of six catalysts are compared, as shown in x  catalysts to catalyze the hydrogenation of acetylene to ethylene is as follows: graphene-NiN2 (B) > graphene-NiN2 (C) > graphene-NiN3 > graphene-NiN2 (A) > graphene-NiN1 > graphene-NiN4. The order of selectivity in 4 > graphene-NiN2 (A) > graphene-NiN2 (C) > graphene-NiN3 > graphene-NiN2 (B) > graphene-NiN1. The catalytic performance of catalysts depends on both reaction activity and selectivity. The lower the activity of the catalyst and the higher the selectivity, the better the catalytic performance. It is clearly seen that graphene-NiN4 has excellent catalytic properties, followed by graphene-NiN2 (A).In the above, the reaction path and energy of the catalyzed by graphene-NiNThus, we also speculate that the catalyst doped with even N atoms makes the catalyst structure distribution more uniform, enhances the overall symmetry, and is more conducive to the hydrogenation of acetylene, whereas the catalyst doped with odd-numbered N atoms is the opposite, which is unfavorable for the acetylene hydrogenation reaction.x  catalyst doped with a various number of N atoms was studied using the theoretical approach of DFT. The results reveal that the order of energy barrier for ethylene formation from acetylene hydrogenation catalyzed using graphene-NiNx  catalyst is graphene-NiN2 (B) > graphene-NiN2 (C) > graphene-NiN3 > graphene-NiN2 (A) > graphene-NiN1 > graphene-NiN4. Among the six catalysts, graphene-NiN4 has the highest selectivity, followed by graphene-NiN2 (A), and the rest are less selective. Having low activity and high selectivity is evidence of the good catalytic performance of this catalyst. Thus, graphene-NiN4 exhibits excellent catalytic performance and is also a potential non-noble metal catalyst for acetylene hydrogenation.In this study, the reaction mechanism of acetylene hydrogenation catalyzed by graphene-NiN


Thanks to the high thermal conductivity of graphene, a record-high operation speed on the order of 200 kHz is realized. Power consumption for π phase shift is 4.65 mW, approximately half of that of the state-of-the-art OPAs. By introducing air trenches, thermal crosstalk is significantly reduced, resulting in an enlarged fill factor. In addition, a novel beam steering scheme in the θ direction is proposed. By applying a 30 mW heating power, a temperature gradient along antennas is generated and beam steering of 2.3° is achieved, satisfying applications such as long-range collision avoidance for autonomous driving.In this paper, high-performance optical phased arrays (OPAs) assisted by transparent graphene nanoheaters and air trenches have been designed and simulated. By directly locating graphene nanoheaters on silicon waveguides, heating efficiency is enhanced by 62.96% compared to conventional structures with 1 μm SiO Improved performances of optical phased arrays have been achieved assisted by graphene nanoheaters and air trenches. Recently, T. Cao et al. theoretically simulated arrays of gradient Au/Bi2Se3/Au nanostructures and other metamaterials and achieved continuous beam steering of 18°.2–6 However, these exciting results require further experimental research before industrial applications. Optical phased arrays (OPAs) based on arrayed waveguides fabricated via CMOS  technology have been considered as one of the most promising technologies to realize solid-state LIDAR system due to their acceptable beam steering angle and potentially reduced cost.Optical beam shaping and steering is indispensable in many applications such as LIDAR (light detection and ranging) systems for three-dimensional imaging and mapping and free-space optical communication.7–16 Beam steering in ϕ direction  is accomplished either by wavelength tuning using the dispersive nature of grating or by fabricating two-dimensional (2D) OPAs.OPAs have been intensively studied in numerous publications.T is temperature difference,  is thermo-optic coefficient of Si, L is heating length and λ is wavelength in vacuum.7Generally, Si-based OPAs are thermo-optically tuned and the phase shift is determined by12,13,16 However, due to strong optical absorption, metal heaters must be separated from waveguides by thick (∼1 μm) overlay such as SiO2, making metal heaters power-inefficient. In addition, poor heat conductivity of SiO2 hinders heat transfer, prolonging heating and cooling time. Recent breakthrough in silicon OPAs utilizes an adiabatic bend to insert p–n–junction heaters into Si waveguides.7,8,10,15 However this approach not only requires careful design, cutting-edge fabrication technique but also may result in optical loss due to Si doping and the adiabatic bend.Metal heaters are widely used in silicon thermo-optic phase shifter.1 Moreover, wavelength tuned OPAs are generally fed by edge coupling,7,9,12,16 resulting in large coupling loss (>3 dB), due to the relatively small dimensions of Si waveguides compared to optical fibers. Furthermore, although 2D OPAs can achieve 2D beam steering using single wavelength, the major disadvantages are the dramatically increased on-chip power consumption, design and fabrication complexity, and more sophisticated driving circuits.1,17As mentioned above, 2D beam steering requires either wavelength tunable laser diode or 2D OPAs. First, it is challenging to design and fabricate chip-integrated semiconductor laser diode with high power, narrow linewidth and wide tunable range. Wavelength-tunable lasers based on silicon platform have only been realized as proof-of-concept demonstrations.θ direction without wavelength tunning.To conclude, it is imperative to realize thermo-optic OPAs with high power-efficiency, fast operation speed and ease of design and fabrication, and a novel low-power beam steering scheme in the 18–20 Experimental results show that graphene has a uniformly high transmission of 97.7% for wide optical spectrum, from 300 nm to 2500 nm.21 The transparent nature of graphene allows us directly locating graphene on Si waveguide without any materials in between. Thus heat generated from graphene could transfer directly to Si waveguide, making graphene nanoheaters more power-efficient.22 In addition, the thermal conductivity of graphene is measured to be 5300 W m−1 K−1,23–25 over 103 times higher than that of silica and air, which are 1.38 W m−1 K−1 and 0.023 W m−1 K−1, respectively. Such high thermal conductivity facilitates heat conduction in the heating and cooling process, making graphene nanoheaters friendlier for high-speed operating situation. Moreover, graphene is compatible with CMOS fabrication process,26 making graphene nanoheaters readier for large-scale photonic integration circuits (PICs).Graphene, a layer of carbon atoms arranged in hexagonal lattice, has received tremendous research interest since its first realization.θ direction is demonstrated.In this paper, we demonstrate improved performance of OPAs assisted by graphene nanoheaters. We show that heating efficiency of the graphene contact heating structure is improved by 62.96% compared to conventional structure with upper cladding. Key parameters including thermal crosstalk, operation speed and power consumption are simulated and the proposed structure is optimized accordingly. In addition, a novel beam steering scheme in the 27–29 Graphene nanoheaters are patterned by standard optical lithography followed by oxygen plasma etching. The width of graphene nanoheater is (2d + w + 440) nm. Throughout this paper, area of the patterned graphene nanoheaters is 100 μm2 and heating power applied to graphene nanoheater is 1 mW, unless otherwise mentioned.Schematic of the proposed structure is shown in 21 When evanescently coupled with Si waveguide, the absorption coefficient of graphene could be further enhanced.30 Fortunately, thanks to the relatively low density state of graphene, optical absorption could be eliminated by appropriate doping of graphene. According to the Pauli blocking effect, if the doping level of graphene is high enough that the Fermi level of graphene exceeds  regime, where hν is energy of incident photons, graphene becomes totally transparent.31–34 Moreover, numerous publications have discussed methods of uniform doping of graphene, including gate doping,35 ion doping36 and chemical doping.37,38 Therefore, the imaginary part of the refractive index of graphene is assumed zero. In addition, since the thickness of single-layer graphene is 0.34 nm, far smaller than the height of Si waveguide, we could reasonably believe that graphene has negligible influence on optical field distribution. Thus in the optical field simulation, we simplified the model by neglecting the presence of graphene.Though only single-layer atom thick, graphene has uniformly strong light absorption for near infrared light (∼2.3%).7,10 In order to obtain large field of view (FOV), the envelope should be as wide as possible. Since the width of the envelope is reversely proportional to the width of emitter, narrow waveguides are preferable.9 Thanks to the large refractive index difference between Si and BOX (∼2), the propagation loss of optical field is negligible for waveguide widths greater than 500 nm. Therefore, we choose w = 500 nm for simulation, enabling single-mode condition, low propagation loss and wide envelop.The far-field emission pattern of an OPA equals to the far-field pattern of one emitter, or the “envelope”, multiplied by an array factor.Neglecting optical absorption of Si, BOX and air, the real parts of refractive indexes at 1550 nm are set at 3.48, 1.45 and 1.00, respectively. The simulated optical field distribution for transverse-electric (TE) mode is shown in 2 overlay, as shown in In order to clearly demonstrate the merit of graphene nanoheaters which allows for direct contact heating Si waveguide, we first consider the structure without air trenches, which is schematically shown in TWGcore) indicates a higher heating efficiency.25 Simulations of thermal field are carried out by a commercial software COMSOL which is based on Finite Element Method. The simulated thermal field distribution of the proposed structure with graphene nanoheaters and the conventional structure are simulated, as shown in d = 500) for both simulations. Heat sources are defined by boundary heat sources. The thermal conductivity for air, Si, SiO2 and graphene are 0.023 W K−1 m−1, 130 W K−1 m−1, 1.38 W K−1 m−1 and 5300 W K−1 m−1, respectively, and the ambient temperature is 293.15 K.The thermal field is associated with the heating efficiency of graphene nanoheater. Given a fixed heating power (1 mW), a higher waveguide core temperature  since the heating length is reduced for a fixed area of graphene (100 μm2 in our simulation).Relationship between 25,39,40 harnessing the poor thermal conductivity of air, further improving the heating efficiency, trading off response speed to some extent though. The structure is schematically shown in TWGcore is drastically enhanced up to 311.17 K, indicating that the heating efficiency is further improved by a factor of 200% compared to the structure without air trench. TWGcore as function of d is shown in TWGcore decreases with increasing width of graphene nanoheater, showing an obviously opposite trend compared to Recent progress introduces air trenches to thermo-optic phase shifters,TWGcore. In the structure with air trench, the above-mentioned process is still valid. However, increasing width of graphene nanoheater enables increasing width of heat dissipation path, leading to a decreasing TWGcore, countering the effect of additional heating power. As a result, TWGcore is affected by the more dominating factor, which is the width of heat dissipation path concluded from our simulation.In the structure without air trench, as the width of graphene nanoheater increases, more heat power is generated and then conducts horizontally through graphene and finally contributes to the waveguide heating, resulting in increasing Pπ) is another important parameter for an OPA's phase shifter, since it is related to the total on-chip power consumption which scales with number of emitters.1 Using d, as shown in N equals to reciprocal of phase shift . The 10–90% rising time and decaying time for graphene nanoheaters without air trench are 2.57 μs and 2.59 μs. As qualitatively analysed above, the rising time and decaying time for graphene nanoheaters with air trench are relatively longer, which are 3.93 μs and 3.96 μs, respectively, due to the poor thermal conductivity of air. The response time as function of d in both structures are shown in d, as opposed to that in the structure with air trench. Explanation to this opposite trend is due to the opposite trend of TWGcore as function of d. Qualitatively speaking, it requires longer time to reach thermal equilibrium for higher TWGcore. The shortest response time is on order of 5.16 μs, corresponding to an operation speed on order of 190 kHz, which is, to our best knowledge, the fastest thermally tuned OPA. Please note this operation speed is limited by 10–90% response time, unlike The transient response is also simulated, as shown in 11,16 Therefore low thermal crosstalk is another design criterion. Thermal crosstalk among emitters is simulated by applying 1 mW heating power to all graphene nanoheaters except for the central one,16 as shown in d = 500 nm) and distances between adjacent waveguides are 4 μm (dWG = 4 μm).Thermal crosstalk is detrimental for OPAs, especially for the large-scale integrated ones, where each emitter requires an independent thermo-optic phase shifter in order to balance phase difference resulted from fabrication imperfection.2, heating up the waveguide underneath, as well as horizontally to adjacent waveguides in the heat deliver process, leading to severe thermal crosstalk. However, in the graphene contact-heating structure, heating flux generated by graphene flows directly to the Si waveguide. Furthermore, the presence of air trenches introduces heat isolation among channels that significantly diminishes thermal crosstalk. Dependence of the temperature at central waveguide core  on waveguide pitch (dWG) with and without air trench is shown in dWG is smaller than 4 μm, the central waveguide suffers from severe thermal crosstalk in both structures, although thermal crosstalk in the structure with air trench is approximately half of that in the structure without air trench. However, when dWG is larger than 10 μm, thermal crosstalk is negligible. It is worth mentioning that the waveguide pitch in the conventional structure is generally on order of 100 μm to reduce thermal crosstalks.16 Using graphene nanoheaters, the waveguide pitch can be reduced by one order of magnitude, giving rise to significantly reduced size of OPA chip, footprint of nonradiative phase-shifting area and consequently enlarged fill factor.As shown in ϕ direction requires smaller antenna pitch and is only an issue of nano-processing technology. However, beam steering in the θ direction is much more challenging. Generally speaking, in an ideal OPA, beam steering range in θ direction should be as wide as possible. However, for some realistic applications, such as collision avoidance for autonomous driving at 100 m distance or longer, beam steering as wide as 2 degree is practically enough since the angle subtended from a pedestrian or a vehicle is merely on order of 1 degree.Achieving wide steering range in the y-axis at the beginning of the antenna array (x-axis, resulting in beam steering in the θ direction.In a grating emitter, each grating tooth can be regarded as an antenna. Therefore, by operating a graphene nanoheater parallel to the na array , a tempeThe grating pitch and duty cycle modeled in this paper are 600 nm and 50%, respectively. Using 2D symmetry, the polar plot of the upward-radiated far-field pattern is shown in 2 overlay, and is further enhanced by a factor of 200% by the presence of air trench. In addition, the operation speed is on order of 200 kHz, twice the previously reported fastest OPA. Moreover, power consumption for π phase shift is as low as 4.65 mW, approximately half of the state-of-the-art OPAs. Furthermore, thanks to the poor thermal conductivity of air, thermal crosstalk is reduced by factor of 448% compared to the conventional structure, leading to footprint of nonradiative area reduced by one order of magnitude and consequently significantly enlarged fill factor. Finally, by applying 30 mW heating power, beam steering of 2.3° is achieved, satisfying applications such as collision avoidance for autonomous driving.In this paper, improved performances of OPAs assisted by transparent graphene nanoheaters have been demonstrated. First, assisted by transparent graphene nanoheaters, the heating efficiency is enhanced by 62.96% compared to the conventional structure with 1 μm SiOThere are no conflicts to declare.


Graphene has been regarded as a potential application material in the field of new energy conversion and storage because of its unique two-dimensional structure and excellent physical and chemical properties. However, traditional graphene preparation methods are complicated in-process and difficult to form patterned structures. In recent years, laser-induced graphene (LIG) technology has received a large amount of attention from scholars and has a wide range of applications in supercapacitors, batteries, sensors, air filters, water treatment, etc. In this paper, we summarized a variety of preparation methods for graphene. The effects of laser processing parameters, laser type, precursor materials, and process atmosphere on the properties of the prepared LIG were reviewed. Then, two strategies for large-scale production of LIG were briefly described. We also discussed the wide applications of LIG in the fields of signal sensing, environmental protection, and energy storage. Finally, we briefly outlined the future trends of this research direction. Since graphene was discovered in 2004, it has attracted the attention of scholars because of its excellent physical and chemical properties, such as ultra-high carrier mobility  [2/g) [Energy and environmental issues have gradually become a formidable challenge for human sustainable development. With the continuous deepening urgency of carbon peaking and carbon neutrality targets, all kinds of clean-energy and renewable-energy materials are ushering in unprecedented new opportunities for development. Graphene, a type of two-dimensional carbon nanomaterial with spcm2/V·s) , high licm2/V·s) ,4, larges) [2/g) , good mes) [2/g) , and ches) [2/g) , etc. The traditional methods for preparing graphene mainly include chemical vapor deposition, redox, mechanical stripping, and epitaxial growth, etc. Chemical vapor deposition  is a proThese above methods for preparing graphene have complex processes, low efficiency, limited choice of substrate materials, and require additional patterning processes to achieve graphene patterning. Therefore, it is necessary to develop a technology with simple operation processes, low cost, high efficiency, wide choice of raw materials, controllable graphene patterning, and a more environmentally friendly preparation process.2 carbon lattice were changed due to a large number of defects. The RGO was not completely equivalent to graphene. Therefore, there are limitations in the preparation and application of this method in graphene-based electronic devices [In recent years, with the rapid development of ultrafast optics, fiber lasers and high-power lasers, laser technology has widely been used in the fields of materials processing, biomedical, and defense industries. Laser processing technology, as an ultra-fine, non-contact, maskless, and programmed processing method, embodies the advantages of high efficiency, flexible patterning, and precise physical property regulation in the preparation and processing of graphene. GO can be converted into reduced graphene oxide (RGO) with the help of laser reduction ,23. Comp devices .2 infrared laser to directly scan on commercial polyimide (PI) films, as shown in In 2014, James M. Tour’s team  successfCompared with the traditional hexagonal honeycomb lattice of two-dimensional graphene, LIG contains a large number of crystalline structures consisting of two pentagons and one heptagon lattice. Due to these unique lattice structures, the graphene can be folded and warped . The lasLIG technology can control graphene’s micro morphology and greatly improve its light utilization and photothermal conversion efficiency . The thrIn this review, we focus on the preparation process, property control of graphene materials, and their applications in the fields of signal sensing, environmental protection, and energy storage, highlighting the latest research results, as illustrated in The surface morphology, as well as chemical, electrical, and mechanical properties of graphene, are related to the laser parameters, laser type, process atmosphere and doping. In this section, we will briefly introduce the influence of various process parameters on LIG morphology and properties during LIG preparation.2, PI was converted into graphene [It was found that the morphology pore size, and thickness of the graphene structure could effectively be tuned by adjusting the laser parameters  ,42. If ographene .2 infrared laser (wavelength 10.6 μm) and a 5 W UV laser (wavelength 355 nm). The experimental results showed that under the same UV and CO2 laser flux, the ablation of PI films formed different morphologies. The surface morphologies with micron-sized and nanometer pores were found under the UV laser, while the sheet structure with micron-sized pores and few pores was produced under CO2 laser. The laser energy density could be controlled with the laser pulse width. Garland et al. [q = 14.4 μm). The LIG produced by low pulse width had a high specific surface area and randomly formed nodule structures (Rq = 30.9 μm). It is worth noting that scanning speed, laser power, wavelength, and pulse width also play a key role in the structure formation of graphene and should be considered simultaneously in the graphene preparation process. Varying these parameters can significantly affect the electrical conductivity, composition, and morphology of LIG e 45,46,,46,47,48d et al.  tested t2 laser, respectively [Selecting appropriate laser parameters  can increase the electrical conductivity of laser carbonized structures on PI surfaces. This is because the laser increases the conductivity by reducing the level of defects within the orbit during graphitization. However, the substrate thickness limits a further increase in conductivity. Biswas et al.  also demectively ,55,56.2 laser, ultraviolet laser (UV), and visible laser.There are three types of lasers used to prepare LIG: infrared CO2 lasers  for the irradiation of PI films to prepare LIG. Laser irradiation region generates localized high temperatures that lead to C–O, C=O, and N–C bond breakage and carbon atom rearrangement, resulting in porous graphene on the film surface [Infrared laser preparation of graphene mainly stems from the photothermal effect, where the absorbed laser energy can be significantly converted into heat due to the high energy density of the laser, and the instantaneous high temperature can break and recombine the chemical bonds of the precursors , as show surface ,66,67,682 infrared lasers. For UV laser, the formation of graphene is mainly due to a photochemical reaction process. Due to the short wavelength and high energy of UV laser, especially when the photon energy is larger than the dissociation energy, the absorbed photon energy can directly break chemical bonds ,57, as sFor visible lasers, both photothermal and photochemical reactions may promote the formation of LIG . RecentlMany scholars have prepared LIG from various precursor materials, as shown in 2 laser, could achieve a lower graphitization temperature due to the ultra-short pulse duration, which is shorter than the time required for heat transfer to the surrounding environment. The results showed that this method could effectively reduce the degree of ablation of wood, and could convert wood and leaves into graphene with good electrical conductivity in an air environment without protective gas [For thermally sensitive materials containing high cellulose content, such as paper, wood, and fabrics, the addition of flame retardants to inhibit ablation and volatilization in ambient air promotes LIG formation ,49,62. Ttive gas .Using laser-induced technology to extract high-quality graphene from nature's abundant precursor materials is simple, economical, and environmentally friendly, laying a solid foundation for the large-scale application of graphene.Although the unique structure of graphene gives it excellent thermal, mechanical and electrical properties, the application of intrinsic graphene in electronics is limited by its zero-bandgap property. It is especially important to obtain graphene with a bandgap tunable within a certain range. To open the bandgap of graphene and solve the application question of graphene in electronics, researchers have explored many methods. One of the most feasible methods is to improve the performance of graphene, or obtain the properties that graphene does not have, by doping. This is because a carbon structure doped with heteroatoms can provide many active sites for electrochemical reactions, thus facilitating ion transfer during electrochemical processes ,83.2, LIG-Co3O4 and LIG-Fe3O4 were successfully prepared. The above-mentioned graphene had excellent redox catalytic activity and is expected to be applied in the electrocatalysis of fuel cells. Clerici et al. [2-LIG, which had good electrochemical properties and high surface area.From the research status of graphene doping, doping technology can be basically divided into in situ and non-in situ. In situ doping is usually achieved by changing the substrate composition or gas environment during laser ablation see . Ye et ai et al.  and Chhei et al.  deposite3BO3 solution with PAA, followed by the preparation of B-LIG using a CO2 laser under ambient conditions, resulting in B-LIG being able to be placed into active electrodes that could be used in flexible micro-supercapacitors. Due to the boron doping, the maximum area capacitance of the prepared devices reached 16.5 mF/cm2, which was three times higher than the undoped devices, and the energy density increased by 5–10 times, making this boron-doped LIG material a great potential for future microelectronics applications. Zhang et al. [In addition, heteroatoms, such as B, N, P, and S, are also important dopants. The direct use of substrate materials containing these atoms or the indirect introduction of these atoms can effectively improve the electrochemical properties of graphene. Peng et al.  first prg et al.  preparedg et al.  also preg et al.  prepared3BO3, followed by another laser irradiation, resulting in the incorporation of N and B atoms into the graphene-like structure. Due to the synergistic effect of N and B, the capacitive properties of NB-dLIG were significantly improved. This method provides a new idea for the preparation of multiple heteroatom co-doped LIGs [2, O2, and SF6 atmospheres, which effectively modulated LIG surface superhydrophobicity or superhydrophilicity [It is very noteworthy that multi-element co-doping is more effective than single element doping due to the synergistic effect of co-doped elements, which can form stronger active regions on its surface ,88. An Lped LIGs . Anotherhilicity .Non-in situ doping refers to the subsequent modification and coating treatment of the formed LIG. Various composites have been successfully prepared by electrodeposition of materials inside or on the surface of graphene. LIGs are commonly used with a variety of materials, such as commercial plastics , construction materials , to form composites with different properties and applications . Luong eLIG technology has emerged as a powerful material fabrication method. Currently, two pathways exist for large-scale production of LIG: in-plane roll-to-roll method, and 3D printing of LIG on a macroscopic scale.2 was prepared in their laboratory. This LIGP was not dependent on any substrate, and could be bent, folded, and cut into specific shapes, which gives it the characteristics of scalable size, mechanical flexibility, and customizable shape. In addition, the authors also indicated that the laboratory-scale process could be upgraded to roll-to-roll continuous fabrication in the future.The roll-to-roll production process is feasible for continuous fabrication of LIG films, as shown in Complexly-shaped graphene components with thicknesses in the micron to millimeter range can be prepared using laser-induced techniques. In some applications where thicker LIG is required, a 3D printing of LIG on a macroscopic scale has been proposed. Sha et al.  preparedSince the discovery of LIG, many scholars have carried out a large amount of research to improve the preparation process of LIG and apply it to various application fields. This section will introduce the research progress of graphene from the perspective of signal sensing, environmental protection, and energy storage.The excellent physicochemical properties and 3D porous structure of LIG make it an ideal candidate for a variety of sensors. The one-step synthesis of patterned graphene has greatly contributed to the development of smart sensors. Researchers have developed a wide variety of LIG-based sensors or sensor devices with modified LIG materials, such as strain sensors, pressure sensors, temperature sensors, humidity sensors, gas sensors, and biochemical sensors, for monitoring various physical and biochemical signals ,97,98,99−1) and good cycling stability (>4000 repetitive cycles)  c. These LIG has high thermal conductivity and low heat capacity, making it an ideal material for thermoacoustic sound sources. Moreover, its porous structure has high sensitivity to weak vibrations and is suitable for sound detection. Therefore, Tao et al.  develope−1). It was reported that the CLIG film can measure wrist pulses, swallowing, and even recognize gestures by the subtle differences in muscle contractions.Flexible wearable pressure sensors play an important role in advanced applications, such as electronic skin, real-time physiological signal monitoring, and human-computer interaction. Pressure sensors based on different mechanisms have been widely used in past decades ,112,113.−1) when the GO concentration was 4 mg/mL and the scan line spacing was 0.12 mm. In addition, this sensor was able to monitor human breathing and contactlessly unlock a combination lock. Han et al. [−1 in the range of 25–45 °C. The sensitivity of the RGO/LIG-based temperature sensor decreased with increasing laser power written to the LIG-based electrode.Temperature sensors are important tools for real-time temperature monitoring in the fields of healthcare and disease diagnosis ,116. LIGn et al.  proposed2 and CO2, which are the most abundant gas species in flue gas. Thus, LIG-based embeddable sensors can be integrated into composite materials, making electronic functional building materials possible. Yang et al. [2 and RGO/MoS2) as gas-sensitive materials to monitor gases, biomolecules, and chemicals. The platform was composed of a fine wire sensing region of LIG and a serpentine connection region of Ag/LIG. This serpentine design increased the tensile properties of the sensor to accommodate different bending variations of the body. Additionally, the platform had good selectivity at slightly higher self-heating temperatures, which allowed the sensor to detect NO2 at a concentration of 1.2 ppb. In addition, Zhang et al. [2 nanoparticles on a PI surface, and CO2 laser irradiation was then applied to both sides to convert them into LIG. The LIG, as an electrode, and the semiconductor ZnS/SnO2, in the middle, formed an ultraviolet photodetector. The lateral electrode structure reduced the total thickness of the device, thus minimizing strain and improving the flexibility of the photodetector. Due to the high flexibility and the ultra-thin characteristics of graphene, the device showed great mechanical flexibility. This simple and cheap manufacturing process is expected to be applied to the field of miniaturized flexible electronics.Due to its three-dimensional porous structure and ultra-high specific surface area, LIG provides sufficient surface locations for gas–solid interactions, making LIG also promising for gas-sensitive detection devices and gas sensing ,123,124.g et al.  developeg et al.  coated aWith the advantages of masklessness, high resolution, low cost, and high throughput, LIG technology has extended its application to biosensors ,58. The From a practical point of view, these above sensors are single-functional and cannot acquire multiple stimuli at the same time. It has been proposed to integrate multiple single-function sensors onto a single substrate, which can detect multiple stimuli simultaneously ,132. ThiDue to its large pore structure, large specific surface area, and excellent surface chemistry, LIG has tremendous potential for many environmental applications, such as anti-pollution systems for desalination and water treatment, air filtration, and generation of anti-bacterial/anti-viral surfaces.Recently, LIG has been considered as a promising candidate material for air filters due to its good microporous structure and strong adsorption of organic molecules . StanforLIG also has many applications in water treatment due to its large specific surface area, tunable surface properties, excellent antifouling activity, and high photothermal conversion efficiency. The sulfur-doped porous LIG prepared by Singh et al.  on sulfoSince the outbreak of neocoronavirus pneumonia, masks, as filters for both inhaled and exhaled air, have played a critical role in controlling the spread of the epidemic . However−2 h−1. This high efficiency was due to the efficient water pumping and high optical absorption of the porous structure. Moreover, the authors also desalinated seawater. The experimental results showed that the water with desalination treatment contained fewer electrolytes than the actual seawater or even domestic water. Thus, graphene membranes can indeed be used for seawater desalination. More importantly, these graphene membranes were self-correcting, and floated firmly at the air-water interface, making the process suitable for practical seawater desalination at the ocean surface [Desalination is a key technology to solve the global water scarcity problem. Existing desalination technologies have a high economic cost. Desalination driven by solar energy is a sustainable means of obtaining fresh water. It is important to seek a carbon material with high solar vapor generation efficiency and stable buoyancy. Li et al.  reported surface . −2 h−1 and a photothermal conversion efficiency of 85.4% at 1 solar light intensity. The evaporation performance of the LIG evaporator in high-concentration NaCl solution (10 wt%) could be maintained for up to 12 h, showing excellent stability and salt tolerance  [To meet the needs of portable and wearable electronic devices, and modern microelectronic systems, miniature energy storage devices are receiving increasing attention. Micro-supercapacitors (MSCs) are promising energy storage devices with fast response to electrochemical processes, high power density, and cyclic stability ,99,140. G layers a. They bolutions . The autolutions . To furtolutions  and pseund MnS2) ,105. Thend MnS2) ,142,143.nd MnS2)  introduc2 MSCs by the spatially shaped femtosecond laser (SSFL) method. It was reported that the SSFL technique can directly complete the processing of electronic devices in batch. The MSC fabricated by this technology had ultra-high energy density (0.23 Wh cm−3), ultra-small time constant (0.01 ms), excellent specific capacitance (128 mF cm−2 and 426.7 F cm−3), and long-term cycling performance, overcoming the current limitations of low efficiency fabrication and low energy density of micro-supercapacitors. Recently, Le et al. [−1. Finally, flexible FsLIG-MSCs were also prepared using FsLIG. After 50,000 cycles, the capacitance of the device retained about 99% of the initial capacitance with good electrochemical stability. The maximum surface energy density of the device was 1.204 μWh cm−2 and the power density was 324.39 µW cm−2, which is comparable to other advanced SCs and MSCs [Although the laser-induced technique has higher fabrication efficiency compared with the conventional method, it is still far from meeting the requirements of rapid mass production and industrialization. Yuan et al.  fabricate et al.  preparedand MSCs ,147,148.−2 and a high cycle life of 400 h. Yang et al. [2S aqueous solution cell. They used a composite of LIG mixed with sulfur as the cathode of this cell. The large specific surface area of LIG sheets (up to 294.69 m2 g−1) provided a large number of surface-active sites. The characterization revealed that the LIG was multilayered, multi-doped and defective, which facilitated the sulfur loading. Due to the synergistic effect of the new redox couple and LIG, when the current density was 0.8 A g−1, the discharge capacity of the battery reached 1654.7 mAh g−1 at the initial cycle. Moreover, 91.2% of the reversible capacity was retained after 328 cycles.With the growth of demand for Li-ion batteries, there is a need to continuously improve the coulomb efficiency, lifetime, stability, and safety factor of batteries. The high porosity, high electrochemical stability, and excellent electronic conductivity of LIG could meet the basic requirements for an ideal collector. A large specific surface area and a good electronic conductivity would reduce the local current density during lithium deposition and slow down the high-volume change of lithium during cycling. Yi et al.  laser irg et al.  proposedProton exchange membrane fuel cells have received the most attention as fuel cells in recent decades. However, production cost and lifetime limit their commercialization applications ,151. TilThis review first outlined the preparation methods of graphene, including chemical vapor deposition, redox, mechanical exfoliation, epitaxial growth, and laser-induced technology. Compared with other methods, laser-induced preparation of graphene is highly efficient, low cost, more environmentally friendly, and has a wide selectivity of precursors. Moreover, laser-induced technology can prepare graphene with controllable patterns without using any catalysts or templates. Next, we introduced the research progress of LIG in the preparation process, which has broadened its application fields by adjusting laser parameters, laser type, precursor materials, atmosphere and doping to achieve the morphology control, conductivity, hydrophilic properties, etc. Thirdly, two methods for large-scale production of LIG were briefly discussed. Finally, the applications of LIG in the fields of signal sensing , environmental protection , and energy storage  were reviewed. (1)Although there have been many kinds of graphene preparation technologies, the large-scale, low-cost, environment-friendly, high-quality, and large-size macro-preparation technologies have not yet made substantial breakthroughs, making it difficult to meet the needs of industrial mass production. Exploring new preparation methods, determining more suitable laser parameters, and finding new precursor materials will provide new possibilities for the large-scale production of high-quality graphene;(2)Single-element doping and two-element co-doping have been studied to prepare LIG, which improves the electrochemical properties to a certain extent, and provides a new idea for multi-element co-doping. Therefore, researchers can further explore other new elements and develop multi-element co-doping to endow LIG with more excellent properties, and endow LIG with broader application prospects;(3)Scientists have developed a variety of sensors, such as pressure sensors, strain sensors, temperature sensors, biosensors, gas sensors, etc. From a practical point of view, these sensors have a single function and cannot acquire multiple stimuli at the same time. Studying multifunctional LIG-based sensors that can detect multiple stimuli is a fascinating direction;(4)When LIG is used in masks, its safety is a primary concern. A Canadian research institute has indicated that the use of masks containing graphene may cause the wearer to inhale graphene particles. To the best of the authors' knowledge, there are no relevant reports on the safety assessment of LIG-based masks for this issue so far. Addressing this issue is an important goal for ongoing research.From the current state of development of LIG, researchers can focus on seeking breakthroughs in the following areas in the development of LIG in the coming years:


Devices composed of monolayer 0.5%G, partially deposited on SiO2 and h-BN were used for transport measurements. We find that the 0.5%G on h-BN exhibits ambipolar transfer behaviours under ambient conditions, in comparison to unipolar p-type characters on SiO2 for the same flake. While intrinsic defects in graphene cause scattering, the use of h-BN as a substrate reduces p-doping.The substrate effect on the electronic transport of graphene with a density of defects of about 0.5% ( Defects in graphene cause scattering and basal plane interactions shift the Dirac-point. However, the chemical structure varies and the carbon lattice may even be amorphous due to the evolution of CO2 during synthesis.4 Thus, in this study we use oxo-functionalized graphene (oxo-G), a type of GO with a more defined structure, as proven in our previous work.3 The oxygen-containing groups on the graphene basal plane and rims of flakes and holes make GO a p-type semiconductor with a typical resistance of 1010–1013 Ω sq−1 5,6 and a band gap of about 2.2 eV.7,8 The reductive defunctionalization of GO leads to a certain type of graphene (G), often named reduced GO (r-GO).4,9 Removal of oxo-groups from the surface can be achieved by chemical reduction,9,10 electrochemical methods,11,12 electron beam treatment13 and was observed in situ by transmission electron microscopy.13 Thermal processing of GO instead leads to a disproportionation reaction forming carbon with additional vacancy defects and CO2.14 In general, the reduction of GO turns r-GO from a semi-conductive material to a semi-metal. Mobility values were determined in field effect transistor (FET) devices.15,16 Generally, the quality of graphene strongly depends on the integrity of the hexagonal carbon lattice. Thus, mobility values of 10−3 and up to 103 cm2 V−1 s−1 were reported,3,17,18 with the resistance fluctuating between 103 and 106 Ω sq−1.19–21 We reported on the highest mobility values of chemically reduced oxo-G (with about 0.02% of lattice defects) of 1000 cm2 V−1 s−1,3 determined by Hall-bar measurements at 1.6 K.Wet-chemically prepared graphene from graphite can be stabilized in solution by covalently bound oxo-groups using established oxidation protocols.22 Up to now, most studies with graphene deposited on h-BN were restricted to measurements with virtually defect-free graphene.23 To the best of the authors knowledge, no studies reported transport measurements based on single layers of GO or oxo-G on h-BN substrates. No studies are reported with graphene derived from GO or oxo-G on single-layer level. Recently, we found that chemical reactions can be selectively conducted close to the rims of defects.24 However, before functionalized devices can be studied, the lack of knowledge on the ambient environment device performances of graphene with defects and the influence of substrates must be addressed. Therefore, we fabricated the devices composed of 0.5%G, partially deposited on SiO2 (SiO2/0.5%G) and h-BN (h-BN/0.5%G)  has been proved to be an excellent substrate for matching graphene-based materials owing to its atomic flatness, chemical inertness and electronic insulation due to a bandgap of ∼5.5 eV.N/0.5%G) . Areas o0.5%G, flakes of 0.5%G were deposited on HOPG surface and examined by scanning tunnelling microscopy (STM) under an ultra-high vacuum (10−10 mbar). The average height of a single 0.5%G flake was determined as 0.9 nm . I (V) spectrum of the 0.5%G surface. Compared to the tunnelling current at the dark region, there exists an apparent suppression of current at the bright region owing to a lower conductivity in the distorted graphene lattices. For the averaged I (V) spectra of the whole area, the metallic behaviour of the 0.5%G flake is found. This phenomenon is also confirmed by the differential conductivity (dI/dV) curves in I/dV curves. The Dirac point in dark region is located at 0.0 V, suggesting low impurity-related doping level. In contrast, the bright regions exhibit a positive shift of the Dirac point of about 50 mV, likely due to the presence of oxygen groups. For the entire scanned areas, the 0.5%G flake exhibits a p-type electronic doping feature with the average Dirac point at about 20 mV.Atomic scale electronic properties of 0.5%G or SiO2/0.5%G, flakes of oxo-G were first deposited on SiO2 substrate by Langmuir–Blodgett technique,29 as shown in 0.5%G flakes were prepared by reduction using vapor of HI/TFA  partially covering the h-BN. The AFM image in 0.5%G. The height profile of the single 0.5%G flake on SiO2 is shown in 0.5%G on HOPG. A major plausible reason is that e.g. water molecules are inevitably adsorbed on the hydrophilic SiO2 surface (treated by O2 plasma) leading to an approximately nanometer-thick hydrogen-bonded water layer and cleaved oxo-groups captured between SiO2 and 0.5%G.33 In contrast, although small amounts of polymer residues are likely trapped between h-BN and 0.5%G, the measured thickness of the same 0.5%G flake on h-BN is ∼1 nm as shown in 0.5%G flake on ∼6 nm thick h-BN (2 (∼1 nm). Therefore, h-BN, as a passivation layer, can not only negate the influence of trapped water on graphene, but also improves accuracy in the AFM thickness measurements of monolayer 2D flakes.ick h-BN  possesse0.5%G supported by SiO2 and h-BN, respectively, are shown in −1, the G peak near 1555–1557 cm−1 and the 2D peak near 2667 cm−1. The D peak of 0.5%G on each interface is mainly activated by defects in the carbon skeletons. The G and 2D peaks closely relate to the quality of graphene. The almost unchanged positions of the three peaks indicate that wrinkles and residual polymers induced during the transfer processes do not produce obvious doping effect on the single layer 0.5%G. We use scatter plots of ID/IGversus Γ2D to further confirm the quality of the 0.5%G in 0.5%G on h-BN, the ID/IG ratio is about 3.3, within the standard deviation of the ID/IG ratio of 3.1 determined on SiO2. Based on the model introduced by Lucchese and Cançado et al.,25,26 the density of lattice defects is related to 0.5% for the devices on h-BN and SiO2. This density of defects relates to the average distance between defects of around 3 nm. The related defect density (nD) is 4.0 × 1012 cm−2 on h-BN and SiO2, respectively, calculated from the equation nD (cm−2) = 1014/(πL2D).25 The Γ2D of the Raman 2D band is sensitive to the presence of defects. For the monolayer 0.5%G on h-BN, only a slightly smaller Γ2D of ∼70 cm−1 is observed than on SiO2 (∼72 cm−1). The same monolayer 0.5%G, partially deposited on SiO2 and h-BN, presents almost the same Γ2D. Therefore, the quality of the investigated flake is the same on SiO2 and h-BN, respectively.Average Raman spectra of the 0.5%G on SiO2 substrate  of 0.5%G on h-BN is shown in 0.5%G on h-BN is observed in ambient environment for sweeping continuously from −50 to 50 V in forward direction and then back to −50 V (backward direction). From the red dashed lines presented in μh) of 5.6 cm2 V−1 s−1 is extracted using the equation μ = (L/W) × (1/(CoxVds)) × (dIds/dVbg),34 where Cox = 1.15 × 10−8 F cm−2. As the output curves (Ids–Vds) exhibit ohmic behaviour . Obviously, electrical transport of the 0.5%G on SiO2 is completely governed by holes with hole mobility μh estimated to about 11.6 cm2 V−1 s−1. In addition, the Ids–Vbg curves exhibit an increase of hysteresis in SiO2/0.5%G device with a shift of Vbg (ΔVbg ≈ 7.3 V) between the forward and reverse sweeps, compared to the h-BN/0.5%G device with ΔVbg ≈ 2.6 V. Substrate change from h-BN to SiO2 induces trapped holes with density higher than 1.6 × 1012 cm−2 using Δnt = ΔVDirac point (Cox/q),2 where q is the elementary charge, ΔVDirac point > 43–20 = 23 V. In general, a high density of charge traps can cause hysteresis and lead to reduced mobility of graphene samples.35 However, as summarized in 2 are higher and the resistance is lower than on h-BN. The main reason for that contradictory finding is that for 0.5%G defects are the dominant scatterers reducing the carrier mobility. This is consistent with Raman results of 0.8%G on SiO2. As shown in Fig. S6,2 V−1 s−1 in ambient and 0.9 cm2 V−1 s−1 in vacuum. However, the Dirac point shifts only from 60 V in ambient to 30 V in vacuum. Those results are in agreement with the STS measurements, which indicate p-doping of 0.5%G in vacuum. It could however be expected that oxo-groups with −I and −M effects,2,3 decorating the rims of vacancy defects, may be responsible for trapping hole carriers. However, the experimental results, such as transport and AFM measurements, give evidence that p-doping is strongly induced by the SiO2 substrate and cleaved oxo-species, such as water or organosulfate, which are trapped between SiO2 and 0.5%G. Therefore, based on the AFM height determination on SiO2, the knowledge about the chemical structure and the reduction mechanism of oxo-G to 0.5%G we propose that molecules, such as water or hydrogensulfate stemming from oxo-G (2 substrate surface and 0.5%G (0.5%G. As a result, spurious dopant molecules may get squeezed out (In contrast to haracter . The poiom oxo-G  are trapnd 0.5%G . In compezed out , as is a0.5%G is a p-doped material and defects determine the scattering of charge carriers. Using h-BN as substrate leads to less trapped molecules, which are responsible for p-doping. In this regard, most likely hydrogen-bonded water and other cleaved oxo-species are captured between SiO2 and 0.5%G causing p-doping, as a consequence of chemical reduction of oxo-G. The ambipolar behaviour with VDirac point of +20 V was therefore observed for the h-BN/0.5%G structure while unipolar p-type response was shown for the same 0.5%G flake on SiO2. Transfer characteristics show a reduction of hysteresis in the h-BN/0.5%G. The mobility of the SiO2/0.5%G is determined to 7.4–14.5 cm2 V−1 s−1 and for h-BN/0.5%G to 5.6–8.5 cm2 V−1 s−1 at ambient conditions.There are no conflicts to declare.RA-009-C9RA09197A-s001


Furthermore, the neutral community model and normalized stochasticity ratio model were applied to reveal the underlying assembly process. Stochastic process and deterministic process dominated the assembly process in wet season and normal season, respectively and similar contributions of deterministic and stochastic processes were observed in dry season. Meanwhile, abundant (relative abundance >0.1%) and rare (relative abundance <0.01%) DAMO bacterial communities were found to be shaped via distinct assembly processes. Deterministic and stochastic processes played a considerable role in shaping abundant DAMO bacterial communities, while deterministic process mainly shaped rare DAMO bacterial communities. Results of this study revealed the dynamics of DAMO bacterial communities in river networks and provided a theoretical basis for further understanding of the assembly process.Denitrifying anaerobic methane-oxidizing bacteria (DAMO bacteria) plays an important role in reducing methane emissions from river ecosystems. However, the assembly process of their communities underlying different hydrologic seasons remains unclarified. In this study, the dynamics of DAMO bacterial communities in river networks of the Taihu Basin were investigated by amplicon sequencing across wet, normal, and dry seasons followed by multiple statistical analyses. Phylogenetic analysis showed that Group B was the major subgroup of DAMO bacteria and significant dynamics for their communities were observed across different seasons (constrained principal coordinate analysis,  Methane is the second most important greenhouse gas with a global warming potential 20–30 times that of carbon dioxide . In receMicrobial-mediated methane oxidation is an effective pathway to reduce methane emissions . AccordiRevealing the assembly process that shape the microbial community is one of the central topics in microbial ecology of freshwater ecosystems . DetermiRivers are typical freshwater ecosystems and serve as key transport channels for the global carbon and nitrogen biogeochemical cycles . In rece2, with the water area constituting 17% of the total area. Sampling campaign was carried out at 18 sampling sites on four crisscross rivers . The nested PCR amplification method was used to amplify the 16S rRNA gene of DAMO bacteria, consisting of an initial PCR with primers qP1mF (5′-GGGCTTGAC ATCCCACGAACCTR-3′)/1492R , and beta diversity index (“Bray-Curtis” distance) were calculated by “vegan” package (version 2.6-2) in the R software (version 4.0.2). One-way ANOVA followed by Duncan’s multiple comparison test was used to compare the alpha diversity and beta diversity across different seasons by “agricolae” package (version 1.3-3) in the R software (version 4.0.2).via constrained principal coordinate analysis (CPCoA) and permutation multivariate ANOVA (PERMANOVA). The CPCoA and PERMANOVA were performed by “amplicon” package (version 1.1.4) and “vegan” package (version 2.6-2) in the R software (version 4.0.2), respectively. The distance-decay patterns of DAMO bacterial communities were calculated as the slope of the linear regression between geographic distance and “Bray-Curtis” similarity (1- “Bray-Curtis” distance) of each pairwise sample. The habitat niche breadth (Bcom) of each ASV was calculated by “spaa” package (version 0.2.2) in the R software  from DAMO bacterial communities were selected for phylogenetic analysis. Phylogenetic analysis was performed by MEGA 7 software using the neighbor-joining method with 1000 bootstrap replicates .4+-N), nitrite nitrogen (NO2−-N), and nitrate nitrogen (NO3−-N) were extracted with 2 mol/L KCl solution for 1 h and then measured colorimetrically by a spectrophotometer  and then determined by the ICP-OES  redundancy analysis (db-RDA) and Mantel test were carried out to reveal the relationships between DAMO bacterial communities and environmental factors. The db-RDA and Mantel test were conducted using “vegan” package (version 2.6-2) and “linkET” package (version 0.0.3.3) in the R software (version 4.0.2), respectively.2 represented the fit of the entire neutral model. The 95% confidence intervals were calculated based on 1,000 bootstrap replicates.The neutral community model (NCM) was used to evaluate the potential contribution of stochastic process in community assembly by predicting the relationship between detection frequency and relative abundance of each ASV . In thisThe normalized stochasticity (NST) ratio was further applied to evaluate the relative importance of deterministic and stochastic processes in shaping DAMO bacterial communities . This moM. oxyfera, M. sinica, M. limnetica, and M. lanthanidiphyla were filtered and 2,599 ASVs  were obtained. After removing ASVs with less than 5 sequences to reduce the PCR bias  than the other seasons  and wet and dry seasons showed higher richness than normal season (p < 0.001). Meanwhile, the similarity of DAMO bacterial communities also exhibited temporal dynamics (p < 0.001).Significant temporal dynamics of alpha diversity and beta diversity of DAMO bacterial communities were observed across different seasons –C. The Sdynamics , and theTo compare the profile of abundant and rare DAMO bacterial communities, 48 ASVs with 1,688,209 (66.59%) sequences and 1,662 ASVs with 55,185 (2.18%) sequences were selected as the “abundant” and “rare” DAMO bacterial communities, respectively. The CPCoA plot and PERMANOVA showed clear differences in whole, abundant, and rare DAMO bacterial communities during wet, normal, and dry seasons . These rp < 0.001). On the contrary, the rare DAMO bacterial communities did not show significant distance-decay patterns  for variations of DAMO bacterial communities and fitted well for the DAMO bacterial communities. Similar observation was found during wet, normal, and dry seasons , which indicated that rare DAMO bacterial communities had narrower niche widths.Similar to the whole DAMO bacterial communities, both deterministic and stochastic processes played important roles in shaping abundant DAMO bacterial communities . During 4+-N, NO3−-N, pH, and Zn, exhibited significant temporal dynamics across different seasons . The db-RDA was further used to reveal the impacts of environmental factors on DAMO bacterial communities (p < 0.001). In addition, the linear regression analysis showed that these metals were significantly correlated with the NST values (p < 0.0001). These results indicated that metals  were the major driving factors affecting the structure and assembly process of DAMO bacterial communities. Meanwhile, similar to the whole DAMO bacterial communities, these metals showed strong correlations with abundant DAMO bacterial communities (r > 0.45) while their correlations with the rare DAMO bacterial communities were weak (r < 0.25), indicating that abundant and rare DAMO bacterial communities responded differently to environmental factors.In this study, most of the environmental factors, such as Cu, Cr, DOC, Mn, Ni, NHmunities . Based oin-situ activity needs to be further explored.Previous studies have confirmed the distribution of DAMO bacteria in the river ecosystem , while tIn this study, the diversity of DAMO bacterial communities was observed to exhibit temporal dynamics –C. The aThe distance-decay patterns were widely prevalent in microbial geographic distributions . In thisRevealing the assembly process was important for understanding the microbial communities . The NCMThe respective roles of deterministic process and stochastic process in shaping DAMO bacterial communities were found to be distinct in different seasons. The stochastic process dominated the community assembly process in wet season, while deterministic process was the major process in normal season . In the Abundant and rare DAMO bacterial communities were observed to exhibit distinct assembly processes. Similar to the whole DAMO bacterial communities, the abundant DAMO bacterial communities were dominated by both deterministic and stochastic processes, while deterministic process shaped the rare DAMO bacterial communities . Our resThis study explored the dynamics and assembly process of DAMO bacterial communities in river networks of the Taihu Basin across different hydrologic seasons. Our results revealed that the diversity and structure of DAMO bacterial communities exhibited significant temporal dynamics while the spatial dynamics were found to be distinct in different seasons. The NCM and NST models together showed that stochastic and deterministic processes both played a considerable role in shaping DAMO bacterial communities. In addition, the abundant DAMO bacterial communities exhibited similar spatiotemporal variations, assembly process, and environmental response with the whole DAMO bacterial communities, but distinct from the rare DAMO bacterial communities. These results provided new clues for DAMO bacterial communities while their contributions to methane reduction need further investigation.The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/SX and SG provided initial concept. RW and TZ carried out field sampling and chemical analyses. RW, SX, YZ, and SG wrote the manuscript. All authors contributed to the manuscript and approved the submitted version.This study was supported by National Natural Science Foundation of China (No. 42007302), Natural Science Foundation of Jiangsu Province (No. BK20190481), China Postdoctoral Science Foundation (No. 2020M681480), and Fundamental Research Funds for the Central Universities (No. 30922010810).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.https://www.frontiersin.org/articles/10.3389/fmicb.2022.1074316/full#supplementary-materialThe Supplementary material for this article can be found online at: Click here for additional data file.


Emerging high-entropy alloy (HEA) films achieve high strength but generally show ineludible brittle fractures, strongly restricting their micro/nano-mechanical and functional applications. Nanolayered (NL) CoCrFeNi/graphene composites are elaborately fabricated via magnetron sputtering and the transfer process. It is uncovered that NL CoCrFeNi/graphene composite pillars exhibit a simultaneous ultra-high strength of 4.73 GPa and considerable compressive plasticity of over 20%. Detailed electron microscope observations and simulations reveal that the monolayer graphene interface can effectively block the crack propagation and stimulate dislocations to accommodate further deformation. Our findings open avenues for the fabrication of high-performance, HEA-based composites, thereby addressing the challenges and unmet needs in flexible electronics and mechanical metamaterials. The dimensions of the initial model were Lx = 201.128 Å, Ly = 206.114 Å, and Lz = 201.95 Å. Before loading, the whole system was equilibrated at 1 K for 100 ps via the Nosé–Hoover isothermal–isobaric (NPT) ensemble, resulting in Lx = 199.479 Å, Ly = 205.718 Å, and Lz = 200.292 Å (a = 3.538 Å). For loading experiments, the micropillars were aligned along the Y-direction, while periodic boundary conditions were used in three axes. Simulations were performed at a constant strain rate (ε) of 109/s using the Nosé–Hoover canonical ensemble (NVT).Molecular dynamics (MD) simulations were performed to illustrate the deformation and fracture behaviors, especially in the vicinity of the CoCrFeNi/graphene interface, using LAMMPS software. Specifically, embedding atomic potential was used to display the interatomic interaction in the HEA . The TerField emission scanning electron microscope  observations were used to understand the growth and morphology of CoCrFeNi HEA films. Columnar grains with high aspect ratios were observed on the cross-sectional HEA film with a film thickness of 625 nm, as shown in The morphology and structure of the monolayer graphene were studied by TEM. 0.1CoCrFeNi HEA film pillar Gr, Y = [111]CoCrFeNi||[010]Gr, and Z = CoCrFeNi||[001]Gr, as shown in More importantly, the experimental observation on crack features indicated that the monolayer graphene interface can strongly hinder and arrest crack propagation. To better understand the effect of the graphene interface on the HEA matrix, MD simulation was employed on an interfacial model system of X = Note that sputtering and transfer might induce damages, such as holes, vacancies, delamination, etc. In this case, the atomic configuration of the CoCrFeNi/intermittent graphene/CoCrFeNi was also considered, as shown in (1)Coupled with HEA sputtering and high-quality monolayer graphene transfer techniques, nanolayered CoCrFeNi/graphene composites can be delicately fabricated;(2)The presented CoCrFeNi/graphene nanolayered composite pillars showed a superior high strength of 4.73 GPa exceeding 20% compressive strain;(3)By postmortem microscope observations and molecular dynamics simulations, the simultaneous high strength and deformability can be interpreted by nanotwins in the HEA matrix and the monolayer graphene interface as a result of confining the dislocation pathway and stimulating dislocations emission and storage.To sum up, we systematically introduced the fabrication, mechanical properties, and deformation behaviors of nanolayered CoCrFeNi/graphene composites. The main findings are as follows:Our preliminary findings not only provide insights into the mechanical properties of CoCrFeNi/graphene nanolayered composites but also offer some clues to the tunable design and feasible fabrication of high-performance, metallic-based composites.