Effects of Impurity Doping on Photoluminescence Properties of APbX₃ Lead Halide Perovskites

Abstract

The impact of introducing heterovalent Bi 3+ impurities in APbX 3 [A = CH 3 NH 3 , CH(NH 2 ) 2 ; X = I, Br] lead halide perovskite single crystals is investigated by means of photoluminescence (PL) spectroscopy. The element analysis reveals that Bi 3+ ions are more easily incorporated into CH 3 NH 3 PbI 3 than into the bromide perovskites CH(NH 2 ) 2 PbBr 3 and CH 3 NH 3 PbBr 3 . The three different halide perovskite single crystals used in this study exhibit a blueshift of the PL spectra at room temperature upon increasing the Bi 3+ concentration. This blueshift is attributed to the weaker photon recycling effect that is induced by shorter PL lifetimes. The experiments reveal that the room‐temperature PL spectra of CH(NH 2 ) 2 PbBr 3 and CH 3 NH 3 PbI 3 are relatively insensitive to impurity doping when compared to the PL spectrum obtained from CH 3 NH 3 PbBr 3 . On the other hand, doping with Bi 3+ affects the low‐temperature PL properties of each sample in a different way, that is, its effect depends on the types of ions in the host material. The mechanism responsible for the shift of the PL spectra and the role of Bi 3+ in lead halide perovskites are discussed.