Temperature Dependence of the Amplified Spontaneous Emission from CsPbBr3 Nanocrystal Thin Films

Cesius lead halide perovskite colloidal nanocrystals are among the most promising perovskite systems for light-emitting devices applications due to their high fluorescence quantum yield and high optical gain at room temperature. In this letter, we report on the first investigation of temperature dependence of amplified spontaneous emission (ASE) properties of thin films of CsPbBr3 nanocrystals. We demonstrate that ASE is strongly temperature-dependent, with a complex variation in temperature of the ASE intensity, threshold, and peak wavelength. The joint investigation of the photoluminescence (PL) spectra below and above the ASE threshold allows us to conclude that the temperature increase results in the formation of disordered subdomains emitting in the low-energy tail of the PL spectra, leading to the existence of three emission regimes with transitions at about 90 and 170 K, with individually different temperature dependences.