ИСТИНА

Methyl-ammonium lead halide perovskites are known to have a subnanosecond luminescence decay time with a relatively high light yield. Exact mechanisms and energy transfer processes in these materials under photo- and X-ray excitation require further research. Here we present luminescence spectra, light yield and decay kinetics changes with temperature and excitation density. The crystals were grown by antisolvent vapor-assisted crystallization. The measurements were performed at P23 beamline of PETRA III storage ring (X-ray region, DESY, Hamburg) and in CELIA, Bordeaux, France (3rd harmonic of femtosecond Ti-sapphire laser) using Z-scan technique. The range of photo-created excitations varied from ~ 1017 to 1022 e-h/cm3. The trends in the temperature and excitation density dependences of MAPbBr3 and MAPbCl3 exciton and side band luminescence are discussed. Changes in the luminescence spectra and kinetics with temperature and excitation density related to the changes of photo-created charge carrier mobilities derived from these experiments can assist in the understanding of properties both of luminescent materials and those for photovoltaics with requirements often contradicting each other.