Influence of the Annealing Temperature on ASE Properties and Carrier Dynamics of Perovskite Films

Quasi-two-dimensional perovskites demonstrate significant potential as laser gain media due to their unique excitonic properties in multilayer configurations. Femtosecond laser spectroscopy techniques, known for their exceptional temporal resolution, allow for the observation of ultrafast dynamic processes at the molecular and atomic levels, surpassing the capabilities of conventional spectroscopic methods. This study employs various spectroscopic methodologies, including stripe light excitation (SLE) and femtosecond time-resolved transient absorption (TA), to investigate the amplified spontaneous emission (ASE) characteristics of Dion-Jacobson type quasi-2D perovskite (PDA)Cs ${}_{\text {n}-1}$ PbnBr ${}_{3\text {n}+1}$ , along with its correlation to carrier dynamics. The experimental findings indicate that higher annealing temperatures can reduce trap-assisted recombination and Auger recombination, thereby enhancing the efficiency of radiative recombination. However, it is observed that excessively high annealing temperatures may lead to a rapid decline in the performance of the quasi-2D perovskite. The research suggests that optimizing the annealing temperature can improve the optical gain characteristics of perovskite films, thereby supporting their application in the field of laser gain media.