Temperature Dependent Hydrogen Bond Toward High Emission in an Emerging Indium-Based Perovskite

Realizing Near-Unity Photoluminescence Efficiency in Antimony-Doped Indium-Based Halides Induced by Strong Electron-Phonon Coupling

Exploring a zero-dimensional (0D) hybrid halide with a large Stokes shift and efficient broad-band emission is highly desirable due to its enormous potential for solid-state lighting (SSL) application. However, it is still challenging to develop a highly emissive 0D hybrid halide with low toxicity and remarkable stability. Herein, we developed a novel indium-based metal halide A5In2Cl16·4H2O (A = doubly protonated 1,4-diaminobutane) whose inorganic octahedrons are completely isolated by the organic cations to form the 0D structure. Experimental and theoretical studies confirmed that Sb-doped A5In2Cl16·4H2O exhibits broad yellow emission with a photoluminescence quantum yield (PLQY) of up to 98%. The intense yellow emission can be attributed to the radiative recombination of triplet self-trapped excitons (STEs) in [SbCl6]3- octahedrons caused by the strong electron-phonon coupling. Benefiting from the excellent stability and photoluminescence performance, A5In2Cl16·4H2O:15%Sb was used as the yellow phosphor to prepare a white-light-emitting diode (WLED) device with a color rendering index of 87.8 and a luminous efficiency of up to 36.18 lm/W, demonstrating its potential in SSL applications. This work provides a guidance for developing environmentally friendly, efficient, and stable ultraviolet (UV)-excited broad-band emission materials.

Lead-free Perovskite with Distorted [InX6]3- Octahedron Induced by Organic Cation and Enhanced PLQY by Sb Doping

In-based halide perovskites have attracted a lot of attention because of their unique broadband emission properties. Herein, a series of In-based hybrid perovskites of (H2MP)2InCl7·H2O (1), (H2EP)2InCl7·H2O (2), (H2MP)2InBr7·H2O (3), and (H2EP)2InBr7·H2O (4) were synthesized under the control of halogen ions and organic cations. 1, 2, and 4 exhibit obvious photoluminescence properties with peaks at 392, 442, and 652 nm, respectively. The effects of the different components on the crystal structure and photoluminescence properties are discussed by calculating the structural distortion of the [InX6]3- octahedron. The photoluminescence properties of 1 and 4 were significantly improved after Sb3+ doping with PLQY values of 57.12 and 41.53%. Finally, a white LED was successfully fabricated with the two doped compounds coated onto the 365 nm blue LED chip.

A zero-dimensional hybrid copper(I) bromide single crystal with highly efficient green emission

Lead-free metal halides are considered as alternatives to lead-based perovskites due to their low toxicity, rich structural diversity, and high luminescence properties. We report millimeter-sized single crystals of a new zero-dimensional (0D) copper(I)-based hybrid material, (AEP)2Cu2Br6·2Br·2H2O (AEP = C6H18N33+), which exhibits bright broadband green photoluminescence (PL) at 510 nm with a Stokes shift of 220 nm and a PL lifetime of 121.1 μs. Density functional theory (DFT) calculations and experimental studies reveal that the green light can be attributed to self-trapping exciton (STE) emission. It is worth mentioning that this crystal has a high photoluminescence quantum yield (PLQY) of 90.5%, which is higher than most copper halides.