Proceedings of 6th International Conference on Hybrid and Organic Photovoltaics (HOPV14)
Publication date: 1st March 2014
Alkylammonium metal trihalide perovskite absorbers have garnered a considerable amount of interest recently in the photovoltaics community. Devices fabricated from these materials achieve very high power conversion efficiencies, already superior to amorphous Si. State-of-the-art devices currently incorporate a planar heterojunction architecture, where the perovskite layer is deposited via conversion of a PbI2 layer to the perovskite phase in a second step. We have further studied this system and demonstrate high photo conversion efficiencies of up to 12%. Intriguingly, we find that films that have not been fully converted to the perovskite phase do not sustain high currents near short circuit. The films were further characterized via time-correlated single photon counting(TCSPC), and the PL lifetimes extracted. We find that MAPbI3 films fabricated through this approach exhibit diffusion lengths of over 200 nm, significantly longer than those obtained via spincoating. This indicates that the photovoltaic properties of the material are highly sensitive regarding the method of film formation and crystallization, which is therefore an important area for further study.