As PSCs have demonstrated a photoconversion energy as high as other commercial solar devices ( CdTe , CIGS , polycrystalline Si ) , one of the key challenges is achieving their long term stable performance when exposed to outdoor conditions . It can be seen from Table 3 and 5 that PSCs are fabricated with a wide variety of materials and design architectures , many of which are intrinsically unstable . It can also be noted that even the similar PSC architectures fabricated at different laboratories resulted in different stability , which is because the durability of these devices largely depends on the purity of starting materials , fabrication methods and conditions , and also the characteristics of the device interfaces . Unlike silicon and thin film solar cells where decades of research has brought them to deliver a stable performance over 20 years with negligible intrinsic degradation , these materials resembles OPVs where instability mostly arises from the materials components itself such as photo - oxidation , change in morphologies over time , and interfacial degradation . [ 273 ] We therefore believe that stability protocols of PSCs are more likely to follow the consensus being developed for OPVs [ 274 ] and DSCs [ 12,243 ] as the device degradation involves chemical modifications . For a detailed overview of the protocols that may be adopted while reporting stability of PSCs , we refer to the comprehensive reports highlighting various ISOS protocols to be adopted while measuring and reporting operational stability ( indoor and outdoor ) . [ 12,243,274 ] Although so far , not many reports have followed any standard protocol while reporting stability of PSCs , we recommend that the perovskite community should follow few considerations while reporting such data . Most importantly the overestimation in PV performance of PSCs due to anomalous hysteresis and their erroneous efficiency reporting ( missing IV data for reverse and forward scan , stabilized maximum power output and statistical analysis ) must be carefully looked at . [ 275 ] For a reliable device characterization , we suggest a measurement protocol developed by Zimmermann et al . [ 276 ] The protocol is derived from standard J - V measurements , power point tracking and stabilized PV parameters as well as characteristics extracted from time resolved current density - voltage measurements . The PSCs research community needs to report stabilized PV performance for both scan directions and preferably the J - V curves at various scan conditions ( delay time , scan rate etc . ) in order to provide a clearer picture of device performance . We recommend a recently published checklist while reporting the PV performance , [ 275 ] ( ii ) while reporting the stability of PSCs , the protocols such as those for dark or indoor testing ( ISOS - D-1 , shelf - life , ISOS - D-2 , high temperature storage , and ISOS - D-3 , damp heat ) or those for outdoor ( ISOS - O-1 - 3 ) [ 273 ] must be followed so that a consensus on the stability is made and a true picture of device performance is obtained .