Proceedings of International Conference Asia-Pacific Hybrid and Organic Photovoltaics (AP-HOPV17)
Publication date: 7th November 2016
FA1−xMaxPb(I1−yBry)3 has been shown as one of the most promising perovskite compositions with a high performance of 20.8% PCE.[1] This composition is designed for an optimal band gap and power conversion performance and not for their stability performance; but for realization of commercial photovoltaic technologies both must be considered. From our previous work, the devices of MAPbI3 without encapsulation in different environments were examined; humidity and oxygen with light were found as the two main degradation factors for perovskite.[2] Herein, the stabilities of mixed cation and mixed halide perovskite in humidity or oxygen plus light have been examined. The humidity tolerance of (MAPb(I1-xBrx)3, x =0…1) and (FA1−xMAxPbI3, x=0…1) films were examined at varying humidity levels to monitor the formation of the hydrated perovskite phase. The films were placed in an inert environmental chamber with nitrogen and controlled humidity levels. The higher bromine ratio can enhance the humidity stability owing to the thermodynamic crystal stability of MAPbBr. Interestingly, both FAPbI3 and MAPbI3 showed inferior stability to humidity compared to mixed cation films.Oxygen and light stability of mixed halide material series was investigated in dry air with 1 sun. For thin film studies, the longer stability was observed for MAPbBr3, but all of the mixed halide films with the inclusion of iodide started to degrade at same time as MAPbI3. These results suggest iodide containing perovskite materials have an inherent instability to environmental stresses that cannot be overcome with ion tuning; however, CH3NH3PbBr3 perovskite shows promising stability for large bandgap photovoltaic operations.
Reference
[1] D. Bi, W. Tress, M. I. Dar, P. Gao, J. Luo, C. Renevier, K. Schenk, A. Abate, F. Giordano, J.-P. Correa Baena, J.-D. Decoppet, S. M. Zakeeruddin, M. K. Nazeeruddin, M. Gra tzel and A. Hagfeldt, Sci. Adv., 2016, 2, e1501170–e1501170.
[2] D. Bryant, N. Aristidou, S. Pont, I. Sanchez-Molina, T. Chotchunangatchaval, S. Wheeler, J. R. Durrant and S. A. Haque, Energy Environ. Sci., 2016, 9, DOI: 10.1039/c6ee00409a.