Optimization of open circuit voltage and stability of Sn–Pb mixed perovskite solar cells by phenyl–ethyl ammonium bromide.

With the rapid development of perovskite solar cells, organic–inorganic hybrid Pb–Sn perovskite solar cells have attracted more and more attention in recent years due to their low toxicity, narrow bandgap and advantages of tandem solar cells. But for the present Pb–Sn mixed perovskite, the open circuit voltage is still at a relatively low level. Herein, phenyl–ethyl ammonium bromide (PEABr) was introduced into the perovskite structure by the method of composition regulation, and high quality and stable Pb–Sn perovskite MA_0.5FA_(0.5-x)PEA_xPb_0.5Sn_0.5I_(3-x)Br_x films and devices were generated. Compared with the Pb–Sn mixed perovskite without component control treatment, the band structure of perovskite optimized by PEABr changes and the transport of charge carriers is promoted due to the introduction of PEA⁺ and Br⁻. In addition, the decomposition of perovskite caused by water and oxygen can be effectively slowed down due to the high stability and hydrophobic characteristics of the two-dimensional material PEA⁺. Finally, the efficiency of the Pb–Sn mixed perovskite device regulated by PEABr increased from 14.2% to 16.1%, and it could be maintained in the nitrogen environment for 14 days without significant efficiency attenuation, while the efficiency of the perovskite device without PEABr regulation decreased significantly. " [ABSTRACT FROM AUTHOR]