Mapping the Space of Inorganic and Hybrid Halides and Their Optical Properties Using Mechanochemistry and First-Principles Calculations

Abstract

Inorganic and hybrid metal halides (MHs) are a class of ionic compounds that attract growing interest due to their richness of structure, properties, and resulting applications. These are largely ionic in nature and hence dominantly follow solid-state synthesis reactions rather than the solution approach. Keeping the importance of these materials in mind, herein, combination reactions of compounds via mechanochemistry is considered as a universal synthetic approach for the synthesis of MHs, and a library of MHs, including all inorganic MHs, ternary (A–B–X) MHs, enormous number of quaternary MHs based on representative 10 double perovskites (A–B–B′–X), and most of the hybrid ones based on randomly selected 49 samples as representative from the 1300 ones, are reported. The fundamental structure–property relationships are well revealed, where most of the MHs exhibit bright photoluminescence and/or magnetic properties for a few materials. Hence, the adopted concept of material design and related with their crystal structure and material properties for such a large number of halide materials not only help in building a library but also provide fundamental guidance to develop new MH materials with selective optoelectronic and magnetic properties..

Excited State Regulated Emission in Hybrid Indium Halides via Crystal Structure Switch

“…As shown in Figure a,e, the undoped samples all exhibit direct band gap characteristics, where the band gaps of PA 6 InCl 9 and PA 4 NaInCl 8 are 4.13 and 3.88 eV, respectively, slightly lower than the experimental values of 4.91 and 4.86 eV. This is because the Perdew–Burke–Ernzerhof (PBE) calculation usually underestimates the band gap of the semiconductor . After successful doping of Sb 3+ , the corresponding band gap values of the samples decreased to 3.80 and 3.61 eV (Figure c,g), respectively.…”

Curious Case of CsPb2Br5: Extremely Soft Structure-Induced Broadband Emission

“…Among different synthesis techniques available, mechanochemistry has been shown as an effective, simple, and solvent free approach to synthesize various metal halides. − To reach our goal, we have studied the structural and optical properties in different time intervals after the synthesis of the bulk powder of CsPb 2 Br 5 via completely solid-state mechanochemical grinding method in ambient condition to omit any interference from ligands and solvents. Particularly, our main objective was to nullify the possible errors that arise from different solubilities of CsBr and PbBr 2 in solvents, , which can lead to the formation of minor side products like 3D CsPbBr 3 and 0D Cs 4 PbBr 6 .…”

High External Quantum Efficiency and Dual-Band Emission of (C7H18N)3Sb2Cl9 for Sensitivity Temperature Sensing

“…The ABX 3 metal halide perovskite (A = organic cation, B = metal cation, and X = halogen anion) structure, composed of corner-shared MX 6 octahedral building blocks, has seen rapid development in recent years and is now a focus of optoelectronic research. − The morphology and size of embedded organic cations can largely determine the molecular structure and dimension . Low-dimensional [one-dimensional (1D) and zero-dimensional (0D)] structures with higher quantum constraints often lead to a more localized electron distribution, resulting in intense photoluminescence properties. − B-site metal ions are typically used as luminescent centers in organic–inorganic hybrid perovskites. , Furthermore, the selection of X (Cl, Br, or I) will affect the optical and electronic band structures of these hybrid perovskites. − …”