Improved Performance and Reliability of p-i-n Perovskite Solar Cells via   Doped Metal Oxides
  Perovskite photovoltaics (PVs) have attracted attention because of their excellent power conversion efficiency (PCE). Critical issues related to large area PV performance, reliability and lifetime need to be addressed. Here, we show that doped metal oxides can provide ideal electron selectivity, improved reliability and stability for perovskite PVs. We report p-i-n perovskite PVs with device areas ranging from 0.09cm2 to 0.5cm2 incorporating a thick aluminum doped zinc oxide (AZO) electron selective contact with hysteresis-free PCE of over 13% and high fill factor values in the range of 80%. AZO provides suitable energy levels for carrier selectivity, neutralizes the presence of pinholes and provides intimate interfaces. Devices using AZO exhibit an average PCE increase of over 20% compared with the devices without AZO and maintain the high PCE for the larger area devices reported. Furthermore, the device stability of p-i-n perovskite solar cells under the ISOS-D-1 is enhanced when AZO is used, and maintains 100% of the initial PCE for over 1000 hours of exposure when AZO/Au is used as the top electrode. Our results indicate the importance of doped metal oxides as carrier selective contacts to achieve reliable and high performance long lived large area perovskite solar cells. 
Achilleas Savva, Ignasi Burgues-Ceballos and Stelios A. Choulis
cond-mat.mtrl-sci