Broadband Emission in Hybrid Organic–Inorganic Halides of Group 12 Metals

Abstract

We report syntheses, crystal and electronic structures, and characterization of three new hybrid organic–inorganic halides (R)ZnBr 3 (DMSO), (R) 2 CdBr 4 ·DMSO, and (R)CdI 3 (DMSO) (where (R) = C 6 (CH 3 ) 5 CH 2 N(CH 3 ) 3 , and DMSO = dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals and bulk polycrystalline powders using a DMSO–methanol solvent system. On the basis of the single-crystal X-ray diffraction results carried out at room temperature and 100 K, all compounds have zero-dimensional (0D) crystal structures featuring alternating layers of bulky organic cations and molecular inorganic anions based on a tetrahedral coordination around group 12 metal cations. The presence of discrete molecular building blocks in the 0D structures results in localized charges and tunable room-temperature light emission, including white light for (R)ZnBr 3 (DMSO), bluish-white light for (R) 2 CdBr 4 ·DMSO, and green for (R)CdI 3 (DMSO). The highest photoluminescence quantum yield (PLQY) value of 3.07% was measured for (R)ZnBr 3 (DMSO), which emits cold white light based on the calculated correlated color temperature (CCT) of 11,044 K. All compounds exhibit fast photoluminescence lifetimes on the timescale of tens of nanoseconds, consistent with the fast luminescence decay observed in π-conjugated organic molecules. Temperature dependence photoluminescence study showed the appearance of additional peaks around 550 nm, resulting from the organic salt emission. Density functional theory calculations show that the incorporation of both the low-gap aromatic molecule R and the relatively electropositive Zn and Cd metals can lead to exciton localization at the aromatic molecular cations, which act as luminescence centers.

Composition‐Dependent Photoluminescence Properties and Anti‐Counterfeiting Applications of A2AgX3 (A = Rb, Cs; X = Cl, Br, I)

“…In the past decade, multinary metal halides have been receiving increased attention due to their wide range of applications, including photodetectors, light-emitting diodes (LEDs), and solar cells. [1][2][3][4][5][6][7][8][9][10] Significant progress has recently been made to Therefore, to change band structures and consequently light emission properties of copper(I) halides, a strategy can be formulated centered around the replacement of Cu(I) with a different metal such as Ag(I). Such substitution is also expected to improve the stability of Cu(I) halides, which is currently one of the significant barriers for considerations of Cu(I) halides for practical applications as materials such as Rb 2 CuX 3 have been shown to degrade in humid air rapidly.…”

Doped Lead Halide White Phosphors for Very High Efficiency and Ultra‐High Color Rendering

“…[18,19] Such emission offers rich opportunities for discovering single-phase white light emitters such as Cs 2 AgInCl 6 ,(EDBE)PbBr 4 (EDBE = 2,2'-(ethylenedioxy)bis(ethylammonium)), C 4 N 2 H 14 PbBr 4 ,( AMP)PbBr 5 .1/2H 2 O (AMP = 1-(2-aminoethyl)piperazine), or (TDMP)PbBr 4 (TDMP = trans-2,5-dimethylpiperaziniium). [16,17,[20][21][22][23][24] Thecolor rendering index (CRI) of these materials can reach high values (ca. 70-90) owing to the broadband emission.…”

Hydrogen Bonding and Broad-Band Emission in Hybrid Zinc Halide Phosphors

“…Photoluminescence from hybrid zinc halides has previously been reported but its origin remains under debate. [3][4][5][6][7][8] Thus, Bushuev et al reported the luminescence to originate from intra-ligands transitions, 5 while Yangui et al reported a luminescence from excitons localized in the organic molecules and self-trapped excitons. 8 The latter assignment of the white emission is similar as the ones commonly reported in hybrid lead halide perovskites.…”