Luminescence and nonlinear optical properties of stable MAPbBr(3) quantum dots in SiO2 mesopores

MAPbBr(3) quantum dots in SiO2 mesopores (similar to 4.4 nm) were prepared by the spin-coating method, and their luminescence and nonlinear optical properties were studied by time-resolved photoluminescence (TRPL) and Z-scan techniques. The results showed that the absorption and photoluminescence peaks are at 464 nm and 476 nm, respectively. The TRPL spectroscopy showed two relaxation processes, a short lifetime (1.04 ns) and a long lifetime (4.49 ns), attributed to the trap-capture recombination and the electron-hole radiative recombination, respectively. Two-photon absorption (TPA) coefficient was 529 cm/GW at 800 nm. The nonlinear signal changed from TPA to saturable absorption with increase in light intensity.