Study on temperature-dependent thermal population and non-radiative relaxation process of the triplet states in Platinum(Ⅱ) octaethylporphyrin

Abstract

The present study focused on examining the thermal population and non-radiative relaxation process by leveraging the unique characteristics of the triplet states of Platinum (Ⅱ) octaethylporphyrin (PtOEP). The investigation of the thermal population process involved the utilization of the luminescence exhibited by the PtOEP triplet state in an oxygen-free environment. Time-resolved spectroscopy was employed to investigate the non-radiative relaxation process occurring on the higher energy levels of the triplet states in the presence of oxygen. The findings indicate that both thermal population and non-radiative relaxation process follow the Boltzmann distribution law. Furthermore, the energy differences obtained from the fitting procedure closely aligned with the energy differences calculated based on the emission spectrum. This observation implies that the underlying reason for the congruence between these two processes is their inherent reversibility.