The first demonstration of room temperature stimulated emission from metal halides －its evidence in CsPbBr3 films

Photoluminescence from CsPbBr3 films prepared by crystallization from the amorphous phase is measured under N2 laser excitation. Stimulated emission due to free exaction-free exaction inelastic collision occurs not only at cryogenic temperature but also elevated temperatures. The intensity of the stimulated emission more rapidly increases with pumping intensity at room temperature than at 77K. The temperature dependence of the stimulated emission measured under 1100kW cm-2 pumping shows the strongest emission intensity at 330K. The stimulated emission survives even at 400K which is equivalent to the exciton binding energy, 35 meV, of CsPbBr3 bulk crystals, although it is completely quenched at temperatures above 460K. FWHM of the emission band is almost constant showing a small value of 8 meV up to the highest temperature, 430K. The present work is the first demonstration of the room temperature (and even above that) stimulated emission from metal halides in the world. This encourages us to explore new laser mediums in metal halides because of their material abundance for high-yield, short-wavelength exciton luminescence and large exciton binding energy