Understanding the emission behaviour of 0D Cs4PbBr6 perovskite nanocrystals at room temperature

Abstract

We report 0D Cs4PbBr6 perovskite nanocrystals emitting at room temperature, synthesized by hot injection technique. Effect of injection temperature (TR) on the emission of Cs4PbBr6 nanocrystals (NCs) has been studied. High-quality NCs are synthesized in the 100 °C–180 °C temperature range. Pure phase Cs4PbBr6 nanocrystals are formed at lower temperatures (TR = 100 °C), while at higher temperatures, CsPbBr3 impurity phase appears along with Cs4PbBr6. Cs4PbBr6 nanocrystals emit blue light with broad emission spectra in the 400–500 nm wavelength range, while a green emission from CsPbBr3 impurities at 520 nm wavelength is observed. The emission spectra from Cs4PbBr6 NCs shows multiple radiative centers in the 400–500 nm range, unaffected by the change in excitation wavelength. The emission of pure Cs4PbBr6 is attributed to charge transfer states of Pb2+ ions and surface states incorporated by presence of ligands on NC surface. Further, it is to be emphasized that the Cs4PbBr6 perovskite NCs are highly stable and maintain their emission even after two years of synthesis.