Extremely photo-luminescent microcrystalline CsPbX3 (X=Cl, Br) films obtained by amorphous-to-crystalline transformation

The compounds CsPbCl3 and CsPbBr3, which are known to be one of the most luminescent semiconductors, show enhanced photoluminescence for thin films prepared by crystallization from the amorphous phase into microcrystalline/polycrystalline states. The microcrystalline state shows more than an order of magnitude stronger free-exciton emission than the polycrystalline state, as well as than bulk single crystal. A possible explanation for this phenomenon is given in terms of excitonic superradiance. The extreme radiance of the thin-film samples is fascinating when considering application in opto-electronic micro-devices.