Investigation of the Amplified Spontaneous Emission Threshold of Cesium Lead Bromide Perovskite Quantum Dots at Different Excitation Wavelengths

The goal of this research is to see how excitation wavelength affects steady-state photoluminescence (PL), time-resolved photoluminescence (TRPL), and amplified spontaneous emission (ASE) in CsPbBr 3 perovskite quantum dots (PQD). At PL and ASE, a plausible mechanism for explaining the excitation wavelength-dependent phenomena was proposed. The PL and ASE properties of CsPbBr 3 PQD as optical materials were examined experimentally at excitation wavelengths of 355–450 nm. An optical parametric amplifier system was used to accomplish optical pumping utilizing a laser pulse with a pulse duration of 70 ps. The ASE threshold was explored and compared the ratio of photons in the pump pulse to band gap energies. The excitation wavelength ( λ ex ) has a considerable influence on the ASE behavior, with high optical densities correlating to optimal excitation, as evidenced by the absorption spectrum, which has a larger absorption coefficient. Furthermore, the energy density at the ASE threshold was closely correlated with the λ ex following the absorption spectrum. Also, it has been demonstrated that changing the excitation wavelength reduces the PQD PL lifetime. Finally, electron-hole pairs can be produced at a reasonable depth from the film’s surface using the appropriate excitation wavelength.