Pressure-Modulated Exciton Dynamics Affecting the Lasing Behavior of CsPbBr₃ Microstrip Resonator

All-inorganic perovskite micro/nanolasers, particularly CsPbBr3, are emerging as promising candidates for nanoscale coherent light sources, which are crucial for advancing high-density integrated optoelectronic devices. This study investigates the spontaneous and stimulated emissions of a single CsPbBr3 microstrip under varying pressure conditions characterized by steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectroscopies. The PL emission, excited with low pump fluence, initially increases and then decreases at a turning point of 0.6 GPa. In contrast, the lasing threshold, excited with high pump fluence, increases monotonically with pressure. The pressure-dependent PL emission is primarily attributed to the competition between recombination pathways through free excitons and trapped excitons, dominated by pressure-tailoring on phonon hardening and surface defect density. The increase in lasing threshold is mainly due to high optical loss induced by the pressure-induced decrease of refractive contrast between the CsPbBr3 microstrip and the surrounding pressure-transmitting medium. These findings reveal that micro/nanolasers resonating in the Fabry–Pérot mode are significantly affected by both the gain medium and resonant optical cavity. This work provides valuable insights into optimizing the performance of micro/nanolasers in integrated optoelectronics and quantum optics under various environmental conditions.