Thermal Degradation Mechanism and Reaction Kinetics of CsPbBr3 Nanocrystals Using the Coats–Redfern Method

Abstract

Cesium lead halide perovskite nanocrystals (NCs) are highly regarded for their potential in solar cells, photodetectors, and X/γ-ray detectors. However, their moisture sensitivity and thermal instability limit their applications, which entail a thorough understanding of their thermal degradation mechanisms. In this study, we investigate the thermal degradation kinetics of CsPbBr₃ NCs spanning temperatures from 25 to 800 °C using thermogravimetric analysis (TGA). The Coats–Redfern method was employed to analyze the kinetics across various models, determining key parameters such as the correlation coefficient (R²), activation energy (E_a), and pre-exponential factor (A). Differential thermogravimetric (DTG) analysis revealed six distinct peaks, indicating six major thermal events. Consequently, the weight loss curve was divided into six zones, and kinetic parameters were calculated for each zone using multiple kinetic models. Utilizing the kinetic triplet, we further determined the thermodynamic parameters including enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy change (ΔG) for each zone. This comprehensive analysis enhances the understanding of the thermal stability and degradation mechanisms of CsPbBr₃, paving the way for advanced applications in various fields.