Two Novel Two-Dimensional Organic–Inorganic Hybrid Lead Halides with Broadband Emission for White-Light-Emitting Diodes

Abstract

Low-dimensional organic–inorganic metal halides (LOMHs) recently have attracted much attention due to their tunable crystal structures and excellent photoelectric properties. The configuration and arrangement of organic cations in LOMHs have significant effect on the structure of inorganic frameworks and luminescence properties. In this work, we systematically explored the "spatial effect" and "hydrogen bonding effect" of organic cations on the structure and properties of LOMHs, by synthesizing three LOMHs including (N-AD)­PbCl4, (N-AD)2Pb2Br7, and (N-AD)4Pb3I12 (N-AD: N-acetylethylenediamine, C4H10N2O). Specifically, (110)-oriented two-dimensional (N-AD)­PbCl4 and (N-AD)2Pb2Br7 with manifest blue-white emissions, originating from the free excitons (FEs) and self-trapped excitons (STEs), respectively. The UV-pumped light-emitting diode (LED)-based on (N-AD)2Pb2Br7 was prepared, and the highest color rendering index (CRI) and correlated color temperature (CCT) were up to 80 and 4484 K, respectively. This proves its potential application in solid-state lighting.

Yellow phosphor based on zero-dimensional antimony halide for white light-emitting diodes

“…Assembled by suitable metals and organic cations, OIMHs are categorized by different dimensions at the molecular level, i.e. , three-dimensional (3D), 10,11 two-dimensional (2D), 12–16 one-dimensional (1D), 17–21 and zero-dimensional (0D) 20,22–26 OIMHs. In 0D OIMHs, particularly, inorganic metal halide components are further apart by the isolation effect of organic cations that the shortest distance of two inorganic components is usually >5 Å, 27–29 making 0D MHs have a much softer lattice, stronger local quantum confinement, and stronger electron–phonon interaction.…”

A 3D lead chloride hybrid exhibits self-trapped emission and exceptional stability

“…As illustrated in Fig. 3a, the title compound single crystals are transparent with a prism shape, whereas they exhibit two PL emissions under 290 nm UV irradiation: high energy narrow emission (360 nm) corresponding to the UV-vis absorption edge (350 nm) is due to the synergic emissions of free exciton (FE) states, which is highly similar to those of reported low-dimensional organic–inorganic hybrids, such as ( N -AD)PbCl 4 ( N -AD: N -acetylethylenediamine, C 4 H 10 N 2 O), 41 (1-mpz)GeBr 4 (1-mpz = (C 5 N 2 H 14 ) 2+ ), 42 (homopiperazine)PbBr 4 , 43 (2,6-dimethylpiperazine) 3 Pb 2 Br 10 , 43 and (benzimidazole) 2 PbCl 4 . 44 Another low-energy broadband emission has been detected at 640 nm.…”