Effect of p-type transition metal dichalcogenide molybdenum ditelluride (p-MoTe2) layer formation in Cadmium Telluride solar cells from numerical analysis
In this paper, we have investigated the effects of transition metal dichalcogenide namely Molybdenum ditelluride (MoTe2) layer formation in between Cadmium Telluride (CdTe) absorber layer and Mo back contact from numerical modeling. The main purpose was to investigate the possible effects of p-type MoTe2 in CdTe thin film solar cell. Energy band line-up in the vicinity of Mo/MoTe2/CdTe interface is investigated to explain the interface properties in terms of various parameters. It was found that p-type MoTe2 has some effects to the performance of CdTe thin film solar cells. Thickness, bandgap energy and carrier concentration of p-MoTe2 all have been varied in the numerical simulation to observe its effects on the cell performance. It was found that when thickness of MoTe2 is less than 20 nm, the cell efficiency decreases, which may be due to the shunting caused by the thinner p-MoTe2. Furthermore, the increase in MoTe2 bandgap results in unfavorable effect to the performance of the cell mainly due to the possibility of electrons to drift towards the back contact and recombination. The increase of the carrier concentration improves the cell performance. This could be attributed to the less recombination of electrons as well as less built in potential (Vbi) at MoTe2/CdTe junction.
A Numerical Analysis of N-MoTe2 in Back Contact of CdTe Solar Cell
Thin-film PV cells with low-cost attractive materials are more appropriate over high-cost silicon-based solar cells as free renewable energy sources. Cadmium Telluride (CdTe) PV cells are widely investigated as one of the ultra-thin film PV cells. They have broadly researched to increase efficiency by improving different front contact and back contact material. In this study, the effect of unintentionally formed n-type Molybdenum Telluride (n-MoTe2) in the back contact interface between the Cadmium Telluride (CdTe) absorber layer and Mo layer has been investigated from a numerical analysis by the facilitation of AMPS-1D software. The variation of short circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF) and efficiency (n) are analyzed by changing four parameters like (i) layer thickness (ii) operating temperature (iii) donor concentration and (iv) sun intensity. From the numerical analysis a moderate performance is observed, where the efficiency of the solar cell is found about 16.532%, Jsc is 21.298 mAcm-2, Voc is 0.99 V and FF is 0.863 for the layer thickness, donor concentration, operating temperature and sun intensity at 60 nm, 1×1016 cm−3, 350K, and 1.1 suns respectively.
Measuring Sheet Resistances of Dielectrics Using Co‐Planar Hydrogel Electrochemical Cells with Practical Applications to Characterize the Protective Quality of Paints on Sculptures
Electrical properties of thin dielectric films at the solid-liquid phase boundary are an important performance characteristic of many devices, coatings and sensors. In this paper, co-polymeric hydrogels of polyacrylic acid co-sulfonic acid, swollen with a salt solution to act as the solid electrolyte, were used to assess interfaces using electrochemical impedance spectroscopy (EIS) in a co-planar geometry. Silane-modified glasses were characterized by the co-planar hydrogel EIS cell and found to be distinguishable based on their surface monolayer chemistry. EIS measurements were also made on primed and painted metal substrates, using both test panels and an outdoor sculpture, Tony Smith's Stinger. The panels were then exposed to accelerated and outdoor weathering and showed degradation on the surface paint layers, which was observable electrochemically using EIS and confirmed visually by SEM. Electrochemical spectral features were compared between data from a standard paint-test cell versus this co-planar hydrogel cell; both cell types were able to measure coating capacitance, providing useful information about the condition of the bulk coating. Yet, sheet resistance (Rs) was a spectral feature seen only by the co-planar hydrogel cell. Thus, it can be concluded that the use of such co-planar hydrogel cells can provide an earlier warning sign to coating degradation and such cells provide a new type of spectral information that is not assessable by the standard geometry.