Lower dimensional nontoxic perovskites: Structures, optoelectronic properties, and applications

Organometal halide perovskites (PVKs) have become rivals to the traditional Si-based solar cells (SCs) due to their extraordinary optoelectronic properties and unprecedentedly increased power conversion efficiency in SCs. However, encountered two main problems, that is, toxicity due to the toxic Pb in their structure and environmental instability. To address the issue of instability, lower-dimensional counterparts (2D PVKs) of the conventional 3D PVKs were introduced. Unfortunately, 2D PVKs also contained a toxic Pb, which hindered their further commercialization. Therefore, Pb-free Bi-based lower-dimensional PVKs were introduced, which not only proved to be eco-friendly but also stable against moisture ingress and thermal stress. Among nontoxic lower-dimensional PVKs, Bi-based 0D PVKs (A3Bi2X9) were extensively utilized due to their isoelectronicity with conventional Pb-based PVKs and enhanced performance in several optoelectronic devices including SCs, photodetectors, memristors, and capacitors. This chapter comprehensively discusses such nontoxic lower-dimensional Bi-based PVKs, their types, structures, optoelectronic properties, and applications in various optoelectronic devices.