Temperature-dependent photoluminescence of pure and Mn-doped CsPbCl3 nanocrystals

Temperature-dependent photoluminescence (PL) properties of Mn-doped CsPbCl3 nanocrystals (NCs) are studied and compared with pure CsPbCl3 NCs by use of steady-state and time-resolved PL spectroscopies. The intrinsic exciton PL of the CsPbCl3 NCs locates at the wavelength range from 405 to 410 nm. The PL intensity in this range decreases rapidly, and the bandgap and linewidth become wider with rising temperature from 78 to 350 K. It is found that the exciton PL shows biexponential kinetics. The short-lived emission is ascribed to the surface trapping state recombination in NCs that has a photoinduced trapped pathway and a temporally resolved peak shift. The long-lived component is due to the band-edge excitonic recombination. Mn dopant open a new emission window at the wavelength range from 560 to 680 nm, of which intensity increases from 140 to 270 K, and then decreases with rising temperature up to 350 K. This unusual temperature dependence is ascribed to the thermal-assisted transition from the excitonic state of NCs to the T-4(1) energy level of Mn2+. This work shows the potential of transition metal element doped perovskite NCs that can take advantage of the coupling between excitons and the d electrons of the dopants for expanded functionalities, such as temperature sensor and light-emitting diode. (C) 2019 Elsevier B.V. All rights reserved.