Proceedings of Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP23)
DOI: https://doi.org/10.29363/nanoge.iperop.2023.088
Publication date: 21st November 2022
Tin halide perovskites, ASnX3 (A = CH3NH3+ (MA+), (NH2)2CH+ (FA+), Cs+ ; X = I–, Br–, Cl–), are promising light absorbers in environmentally-friendly, solution-processed solar cells. The wide bandgaps of bromide-containing tin perovskites, ASnI3–xBrx, make them attractive materials for use as the top-layer absorber in tandem solar cells, as well as in single junction solar cells for indoor applications.
In the present work, a series of ASnI3–xBrx films was systematically fabricated by varying the A-site (FA+, MA+, Cs+) and X-site (I–, Br–) ions. The use of solvent-coordinated SnBr2 complex [1] as a high purity source of bromide combined with Sn(IV) scavenging treatment [2] help to ensure that the optimal film quality across the compositional space is realized. The energy levels and electronic properties of the films were characterized by photoluminescence (PL) and photoemission yield spectroscopy (PYS) measurements. The films with high PL lifetime and favorable energy level alignment resulted in superior device efficiency when evaluated in standard single junction solar cells. The best power conversion efficiency of 7.74% was obtained when the composition was FA0.75MA0.25SnI2.25Br0.75 [3].