Negligible Bowing Effect of Bandgap and Lattice Constant in a Variety of Compositions using Large Tilt Distortion in a Cesium–Lead Mixed‐Halide System

• DOI: 10.1002/adom.202300682
• Publication Date: 2023-05-31T05:29:51Z
• Authors: Yujin Nam; Maengsuk Kim; Se‐Yun Kim; Jina Jung; Gunasekaran Rajen...; Joon‐Hyung Lee; Sangwook Lee; Chul‐Hong Park; Young‐Woo Heo
• Keywords: Bowing; Caesium; Lattice constant

Abstract Halide perovskites have broad bandgap tunability, making them suitable for diverse applications in optoelectronics and photovoltaics. The optical of halide varies almost linearly with the ionic size, therefore, it can be controlled through compositional engineering. However, mechanism underlying this low‐bandgap variation is not yet fully understood. Thus, study comprehensively investigates bowing cesium–lead mixed‐halide using engineering demonstrates that extremely small a variety compositions including Cl, Br, I. Subsequently, density functional theory calculations, suggested antibonding character valence band maximum, tilt distortion ions, entropy effect leading to equal participation various ions around Pb are collectively responsible bowing.