The recombination mechanisms leading to amplified spontaneous emission at thetrue-green wavelength in CH3NH3PbBr3perovskites

We investigated the mechanisms of radiative recombination in aCH3NH3PbBr3hybridperovskitematerialusing low-temperature, power-dependent (77 K), and temperature-dependentphotoluminescence(PL)measurements. Twobound-excitonic radiative transitions related to grain size inhomogeneity were identified.Both transitions led to PL spectra broadening as a result of concurrent blue and red shifts of these excitonicpeaks. The red-shifted bound-excitonic peak dominated at high PL excitation led to atrue-green wavelength of 553 nm for CH3NH3PbBr3powders that areencapsulated in polydimethylsiloxane. Amplified spontaneous emission was eventually achieved for anexcitation threshold energy of approximately 350 μJ/cm2. Ourresults provide a platform for potential extension towards a true-green light-emittingdevice for solid-state lighting and display applications.