Excited-State Properties of Defected Halide Perovskite Quantum Dots: Insights from Computation

• DOI: 10.1021/acs.jpclett.0c03317
• Publication Date: 2021-01-20T14:41:31Z
• Authors: Carlos Mora Perez; Dibyajyoti Ghosh; Oleg Prezhdo; Sergei Tretiak; Amanda J. Neukirch
• Keywords: Chemical Sciences not elsewhere classified; spectra; light-emitting diodes; Biophysics; 01 natural sciences; CsPbBr 3 QDs; plague CsPbBr 3 QDs; Sociology; Space Science; time-dependent density; CsPbBr 3 clusters; defect tolerance; QD perovskites; Defected Halide Perovskite Quantum Dots; Excited-State Properties; UV; 0104 chemical sciences; LED performance; Medicine; Computation CsPbBr 3 quantum dots; Physical Sciences not elsewhere classified; trap states; Biological Sciences not elsewhere classified; Br vacancies; formation energy vacancy defects

CsPbBr3 quantum dots (QDs) have been recently suggested for their application as bright green light-emitting diodes (LEDs); however, their optical properties are yet to be fully understood and characterized. In this work, we utilize time-dependent density functional theory to analyze the ground and excited states of the CsPbBr3 clusters in the presence of various low formation energy vacancy defects. Our study finds that the QD perovskites retain their defect tolerance with limited perturbance to the simulated UV-vis spectra. The exception to this general trend is that Br vacancies must be avoided, as they cause molecular orbital localization, resulting in trap states and lower LED performance. Blinking will likely still plague CsPbBr3 QDs, given that the charged defects critically perturb the spectra via red-shifting and lower absorbance. Our study provides insight into the tunability of CsPbBr3 QDs optical properties by understanding the nature of the electronic excitations and guiding improved development for high-performance LEDs.