The all-inorganic α-CsPbI₃ perovskite, which possesses an optimal bandgap, encounters significant challenges related to low phase stability and high humidity sensitivity. In response to these issues, Zhao Yixin and colleagues from Shanghai Jiao Tong University published a paper in the Journal of the American Chemical Society on September 24, 2018, demonstrating that a simple post-treatment using phenyltrimethylammonium bromide (PTABr) can achieve bifunctional stabilization, including gradient bromine doping (or alloying) and surface passivation.
Treating CsPbI₃ with PTABr induces a blue shift of less than 5 nanometers in the UV-visible absorption spectrum but significantly stabilizes the perovskite phase, enhancing its overall stability. Consequently, highly stable CsPbI₃-based perovskite solar cells treated with PTABr exhibit reproducible photovoltaic performance, with a champion efficiency of up to 17.06% and a stabilized power output efficiency of 16.3%. Thus, the one-step bifunctional stabilization of perovskites through gradient halide doping and surface organic cation passivation offers a novel and promising strategy for designing stable and high-performance all-inorganic lead halide perovskites.
