Construction of Compact Methylammonium Bismuth Iodide Film Promoting Lead-Free Inverted Planar Heterojunction Organohalide Solar Cells with Open-Circuit Voltage over 0.8 V
The Journal of Physical Chemistry Letters, 8 (2):
394-400 (2017)PMID: 28048938.DOI: 10.1021/acs.jpclett.6b02578
Abstract
A bismuth-based organohalide material, methylammonium bismuth iodide (MA3Bi2I9), has been recently explored as an efficient lead-free light absorber in photovoltaic applications. However, the poor surface morphology of the MA3Bi2I9 film fabricated via conventional one-step spin-coating methods has limited the performance of the device. In this work, a smooth, uniform, and compact MA3Bi2I9 thin film was realized by a novel two-step evaporation–spin-coating film fabrication strategy for the first time. Taking advantage of the superior MA3Bi2I9 thin film, the best-performing inverted planar heterojuncion photovoltaic device exhibited a power conversion efficiency of 0.39\% with open-circuit voltage as high as 0.83 V, which demonstrated the lowest loss-in-potential to date in MA3Bi2I9-based solar cells. Moreover, the facile film fabrication strategy utilized in this work paves the way for high reproducibility of lead-free organohalide films and devices.