Effects of Bi and Sb ion incorporation on the optoelectronic properties of mixed lead–tin perovskites

Doping with small densities of foreign ions is an essential strategy for tuning the optoelectronic properties of semiconductors, but the effects of doping are not well-understood in halide perovskites. We investigate the effect of Bi3+ and Sb3+ doping in lead–tin perovskites. Films doped with small amounts of BiI3 and SbI3 show greatly increased non-radiative recombination at precursor doping concentrations as low as 1 ppm for Bi3+ and 1000 ppm for Sb3+. We rationalize such behaviour by density functional theory (DFT) simulations, showing that these metal ions can be incorporated in the perovskite crystal by introducing deep trap levels in the band gap. Having found that very small amounts of Bi3+ greatly reduce the optoelectronic quality of lead–tin perovskite films, we investigate the presence of Bi impurities in perovskite precursor chemicals and find quantities approaching 1 ppm in some. In response, we introduce a facile method for removing Bi3+ impurities and demonstrate removal of 100 ppm Bi from a perovskite ink. This work demonstrates how the incorporation of small concentrations of foreign metal ions can severely affect film quality, raising the importance of precursor chemical purity.

Keywords

Bromine compounds, Carrier concentration, Crystal impurities, Germanium compounds, Metal halides, Photoionization, Semiconducting antimony compounds, Semiconducting bismuth compounds, Semiconductor doping, Tin compounds

Subject (DDC)

600 - Technik, Medizin, angewandte Wissenschaften

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ISBN

ISSN

2050-7526
2050-7534

Language

English

Created during FHNW affiliation

Yes

Strategic action fields FHNW

Zero Emission

Publication status

Published

Review

Peer review of the complete publication

Open access category

Hybrid

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Citation

Rombach, F. M., Gregori, L., Sidler, A., Whitworth, J., Zeiske, S., Jin, H., Hung, E. Y.-H., Motti, S., Caprioglio, P., Armin, A., Lenz, M., Meggiolaro, D., De Angelis, F., & Snaith, H. J. (2025). Effects of Bi and Sb ion incorporation on the optoelectronic properties of mixed lead–tin perovskites. Journal of Materials Chemistry C, 13(10), 5161–5171. https://doi.org/10.1039/d4tc02162b

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