The formation of CH3NH3PbBr3 nanocrystals and silicone resin composites greatly improves the stability of CH3NH3PbBr3 nanocrystals against water, heat and UV exposure.

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Optical properties of InGaAs/GaNAs superlattice are investigated by the photoluminescence and reflectance measurements. A quantum well (QW) emission PM (centered at ≈1.2 eV) and a broad low‐energy emission (LEE) band, which can be resolved to three peaks PA′, PA, and PB (0.77, 0.83, and 0.92 eV) are observed. The peak positions of the LEE exhibit S‐shaped behavior, whereas the QW emission shows a red shift with increasing temperature. The LEE bands are attributed to N‐related deep‐level localized state. The photoluminescence (PL) peak of QW exhibits a significant blue shift and saturation effect with increasing excitation density, which is interpreted in terms of the band‐bending model in the InGaAs/GaNAs short‐period superlattice (SPSL) with a type II band alignment. Furthermore, carrier transfer among these N‐related localized states is elucidated by examining the temperature‐dependent photoluminescence. Such carrier transfer is also demonstrated by the thermal effect under high excitation density.

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Temperature and excitation dependent photoluminescence (PL) of InGaN epilayer grown on c-plane GaN/sapphire template by molecular beam epitaxy (MBE) has been systematically investigated. The emission spectra of the sample consisted of strong multiple peaks associated with one stimulated emission (SE) located at 430 nm and two spontaneous emissions (SPE) centered at about 450 nm and 480 nm, indicating the co-existence of shallow and deep localized states. The peak energy of SE exhibiting weak s-shaped variation with increasing temperature revealed the localization effect of excitons. Moreover, an abnormal increase of the SPE intensity with increasing temperature was also observed, which indicated that the carrier transfer between the shallow and deeper localized states exists. Temperature dependent time-resolved PL (TRPL) demonstrated the carrier transfer processes among the localized states. In addition, a slow thermalization of hot carriers was observed in InGaN film by using TRPL and transient differential reflectivity, which is attributed to the phonon bottleneck effect induced by indium aggregation.