The Rb₇Bi_3−3xSb_3xCl₁₆ Family: A Fully Inorganic Solid Solution with Room‐Temperature Luminescent Members

Abstract

Low‐dimensional ns2‐metal halide compounds have received immense attention for applications in solid‐state lighting, optical thermometry and thermography, and scintillation. However, these are based primarily on the combination of organic cations with toxic Pb2+ or unstable Sn2+, and a stable inorganic luminescent material has yet to be found. Here, the zero‐dimensional Rb7Sb3Cl16 phase, comprised of isolated [SbCl6]3− octahedra and edge‐sharing [Sb2Cl10]4− dimers, shows room‐temperature photoluminescence (RT PL) centered at 560 nm with a quantum yield of 3.8±0.2 % at 296 K (99.4 % at 77 K). The temperature‐dependent PL lifetime rivals that of previous low‐dimensional materials with a specific temperature sensitivity above 0.06 K−1 at RT, making it an excellent thermometric material. Utilizing both DFT and chemical substitution with Bi3+ in the Rb7Bi3−3xSb3xCl16 (x≤1) family, we present the edge‐shared [Sb2Cl10]4− dimer as a design principle for Sb‐based luminescent materials.

The Rb7Bi3−3xSb3xCl16 Family: A Fully Inorganic Solid Solution with Room‐Temperature Luminescent Members

“…3À octahedra (green with green chlorine atoms) separated by Rb + cations (purple). [31] To further characterize these properties and gain insight into the source of emission in Rb 7 Sb 3 Cl 16 ,wef irst conducted aseries of steady-state spectroscopic experiments:excitationpower dependent PL (dW-PL) at RT (Supporting Information, Figure S9), temperature-dependent PLE (dT-PLE) and PL (dT-PL) from RT down to 12 K ( Figure 1c,d;S upporting Information, Figure S10).…”

“…a) The crystal structure of Rb 7 Bi 3 Cl 16 as viewed along the [100] axis containsB idimers and octahedra (blue with green chlorine atoms) separated by Rb + cations (purple). [31] b) The crystal structure of Rb 7 Bi 2.6 Sb 0.4 Cl 16 as viewed along the [100] axis containsm ixed Sb/Bi dimers and octahedra (cerulean with green chlorine atoms) separated by Rb + cations (purple). [31] c) The crystal structure of Rb 7 BiSb 2 Cl 16 as viewed along [110] contains mixed Sb/Bi dimers and octahedra (aquamarine with green chlorine atoms) separated by Rb + cations (purple).…”

“…[31] b) The crystal structure of Rb 7 Bi 2.6 Sb 0.4 Cl 16 as viewed along the [100] axis containsm ixed Sb/Bi dimers and octahedra (cerulean with green chlorine atoms) separated by Rb + cations (purple). [31] c) The crystal structure of Rb 7 BiSb 2 Cl 16 as viewed along [110] contains mixed Sb/Bi dimers and octahedra (aquamarine with green chlorine atoms) separated by Rb + cations (purple). [31] d) The normalizedR T PL (solid) and PLE (dashed)s pectra of Rb 7 Bi 3À3x Sb 3x Cl 16 .…”

“…[31] c) The crystal structure of Rb 7 BiSb 2 Cl 16 as viewed along [110] contains mixed Sb/Bi dimers and octahedra (aquamarine with green chlorine atoms) separated by Rb + cations (purple). [31] d) The normalizedR T PL (solid) and PLE (dashed)s pectra of Rb 7 Bi 3À3x Sb 3x Cl 16 .…”

The Polymorphic Nature of M3BiBr6 Halides (M=Cs, Rb) and their Reversible Intercalation with Water to Isomorphous Hydrates at Room Temperature

“…[1] Especially materials based on bismuth halides are investigated, because they are expected to be non-toxic, [2] however, some of them proved to be better suited as luminescent materials. [3] Among the many compounds discussed are alkali metal salts of type M 3 BiX 6 (M = Rb, Cs; X = Br, I), which are sometimes referred to as "zero-dimensional perovskites", because of their isolated [BiX 6 ] octahedra, or as "double halide perovskites". [2][3][4][5] One of the major issues in the application of bismuth halide absorber materials is their inherent tendency to hydrolyze.…”