This paper reports the transient photoluminescence (PL) properties of an InGaN/GaN multiple quantum well (MQW) light-emitting diode (LED) with green emission. Recombination of localized excitons was proved to be the main microscopic mechanism of green emission in the sample. The PL dynamics were ascribed to two pathways of the exciton recombination, corresponding to the fast decay and the slow decay, respectively. The origins of slow decay and fast decay were assigned to local compositional fluctuations of indium and thickness variations of InGaN layers, respectively. Furthermore, the contributions of two decay pathways to the green PL were found to vary at different emission photon energy. The fraction of fast decay pathway decreased with decreasing photon energy. The slow radiative PL from deep localized exciton recombination suffered less suppression from non-radiative delocalization process, for the higher requested activation energy. All these results supported a clear microscopy mechanism of excitation-emission process of the green MQW LED structure.

Organic–inorganic hybrid perovskites are emerging as promising light-emitting materials due to their superior photophysical properties. Poor surface coverage creating substantial pinholes and shunt paths, nevertheless, is one of the most severe problems that hinder the further development of perovskite light-emitting diodes (PeLEDs). Here in this work, we demonstrated a fabrication of PeLEDs by using a robust, stable, and highly transparent poly(methyl methacrylate) (PMMA) polymer to passivate the pinholes of CH ₃ NH ₃ PbBr ₃ emissive layer and hence reduce the non-radiative losses through the shunt paths formed by the pinholes. Uniform surface coverage and reduced leakage current were achieved. Green electroluminescence (EL) emission centered at ~534 nm was greatly boosted by a factor of 10 at 8 V with optimizing the thickness of the PMMA modifier. This facile and universal technique provides an effective way to circumvent the poor formation of the CH ₃ NH ₃ PbBr ₃ perovskite film and may be very helpful in the development of PeLEDs.

Copper-based metal halides are a group of potential scintillation materials with non-toxic and environmentally friendly properties. However, the slow growth rate of their crystals hinders their applications. In this paper, an organic [N(C₂H₅)₄]₂Cu₂Br₄ crystal was proposed for X-ray scintillation imaging. It was successfully synthesized using a fast solution-phased approach with a production rate of 100 mg/min. The photoluminescence quantum yield of the [N(C₂H₅)₄]₂Cu₂Br₄ crystal is 55% with good stability. More importantly, it has a bright blue emission with a large Stokes shift originating from self-trapped excitons, which contribute to the reabsorption-free characteristic. Its scintillation properties, with a light yield of 7623 photons MeV⁻¹ and remarkable X-ray imaging performance, provide important guidance for the further study of X-ray scintillation crystals.

Fast and convenient synthesis of zero-dimensional (0D) cesium-copper(i) halide (Cs₃Cu₂X₅ (X = Cl, I)) single crystals (SCs) is critical to achieve practical radiography.