Excitation wavelength dependence of photoluminescence flickering in degraded MAPbI₃ perovskite and its connection to lead iodide formation

Summary, in English

Metal halide perovskite semiconductors often exhibit photoluminescence blinking and flickering when luminescence of individual small nano- or even microcrystals is monitored. The nature of these fluctuations is not well understood but must be related to the presence of metastable non-radiative recombination channels and efficient charge migration in these materials. Here we report on the excitation wavelength dependence of photoluminescence flickering effect in degraded methylammonium lead iodide (MAPbI₃) thin films. While the luminescence intensity is temporary stable when excited in the blue region with wavelength shorter than 530 nm, excitation with red light (wavelength longer than 530 nm) results in luminescence flickering. It is hypothesised that the wavelength dependence reflects the excitation energy dependence of the photochemical mechanism that switches non-radiative recombination channels on and off. The effect can also be related to hindered charge carrier diffusion due to their localization in the interfacial layer between MAPbI₃ and PbI₂ which is formed in the course of degradation.

• Author: Alexander Kiligaridis; Aboma Merdasa; Carolin Rehermann; Eva L. Unger; Ivan G. Scheblykin
• Department/s: Chemical Physics; NanoLund: Centre for Nanoscience
• Publishing year: 2020
• Language: English
• Publication/Series: Journal of Luminescence
• Volume: 222
• Links: http://dx.doi.org/10.1016/j.jlumin.2020.117129
• Document type: Journal article
• Publisher: Elsevier
• Topic: Atom and Molecular Physics and Optics
• Keywords: Blinking; Degradation; Lead iodide; Luminescence excitation spectrum; Perovskite; Photoluminescence
• Status: Published
• ISBN/ISSN/Other: ISSN: 0022-2313