Reversible Pb 2$\mathplus$ /Pb 0 and I - /I 3 - Redox Chemistry Drives the Light-Induced Phase Segregation in All-Inorganic Mixed Halide Perovskitesстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 3 февраля 2022 г.
Аннотация:Tunability of optoelectronic properties of lead halide perovskites achievedthrough halide mixing can potentially enable their multiple applications, forexample, in tandem solar cells and light-emitting diodes. However, mixedhalide perovskites are unstable under illumination due to their segregation toBr-rich and I-rich phases, which negatively affects the performance and theoperational stability of devices. Research efforts over the past years provideda substantial understanding of the factors influencing light-induced halidephase segregation. While several mechanisms have been proposed, none ofthem could account for all available experimental data; and hence the originof the effect is still under active debate. Herein, the photodegradation ofCsPbI2Br and Cs1.2PbI2Br1.2 is thoroughly investigated using a set of complementarytechniques. In situ atomic force microscopy provides a visualizationof the real-time halide phase segregation dynamics demonstrating thatiodoplumbate is selectively expelled from the mixed halide perovskite grainsand nucleates as a separate I-rich phase at the grain boundaries. A mechanismbased on the reversible Pb2+/Pb0 and I−/I3− redox (photo)chemistry isproposed, which explains the experimental findings and other previouslyreported results. Furthermore, it sheds new insights on the underlyingmechanisms of multiple phenomena related to light- or electric field-induceddegradation of various lead halide perovskites.