Charge-Carrier Trapping Dynamics in Bismuth-Doped Thin Films of MAPbBr₃ Perovskite

Abstract

Successful chemical doping of metal halide perovskites with small amounts of heterovalent metals has attracted recent research attention because of its potential to improve long-term material stability and tune absorption spectra. However, some additives have been observed to impact negatively on optoelectronic properties, highlighting the importance of understanding charge-carrier behavior in doped metal halide perovskites. Here, we present an investigation of charge-carrier trapping and conduction in films of MAPbBr 3 perovskite chemically doped with bismuth. We find that the addition of bismuth has no effect on either the band gap or exciton binding energy of the MAPbBr 3 host. However, we observe a substantial enhancement of electron-trapping defects upon bismuth doping, which results in an ultrafast chargecarrier decay component, enhanced infrared emission, and a notable decrease of chargecarrier mobility. We propose that such defects arise from the current approach to Bidoping through addition of BiBr 3 , which may enhance the presence of bromide interstitials.

Understanding and suppressing non-radiative losses in methylammonium-free wide-bandgap perovskite solar cells

“…Given the long lifetimes of trapped carriers in lead halide perovskite semiconductors, 47 the shorter time period between photoexcitation pulses results in trap filling and population build-up. We investigate the influence of this higher repetition rate by employing a model in which the electron and hole first-order decay rates can vary, as previously implemented, 48 whilst also including the effect of diffusion to account for the rapid early time decay, seen in previous studies. 49 (More details of the model are provided in the ESI.…”

Low-noise X-ray PIN photodiodes made of perovskite single crystals by Solution-processed doped epitaxial growth

“…MHPSCs. Among the 16 types of metal bromide investigated, bismuth bromide [31][32][33][34][35][36] (BiBr3) and silver bromide 37 (AgBr) are considered the most effective donors and acceptors, respectively, due to the high thermally induced diffusion current.…”

Mixed Group 14–15 Metalates as Model Compounds for Doped Lead Halide Perovskites

“…They also observed a darkening of the crystal color and proposed that this is due to band gap narrowing [19] . However, subsequent investigations showed that the color change is due to the introduction of defects [20–22] . The effect of bismuth doping on the photovoltaic performance of lead iodide perovskites is a point of ongoing research: Troshin and Tress found that Bi doping is highly detrimental to the power conversion efficiency of (CH 3 NH 3 )PbI 3 solar cells [23, 24] .…”