Exciton recombination kinetics in high quality CsPbBr3 thin films

Cs-based inorganic perovskites represent a very promising alternative to hybrid organic perovskites, given their better long-term stability and the impressive radiative yield. Therefore such materials are extremely attracting not only for tandem photovoltaic cells but also for the realization of efficient LEDs and lasers, being possible to cover a spectral range from NUV to NIR depending on the halide composition. In this contribution we present time-integrated (TI) and picosecond time-resolved (TR) photoluminescence (PL) results to assess the exciton recombination dynamics in high quality CsPbBr3 thin films, varying several experimental parameters ( temperature, excitation intensity, excitation photon energy). An increase of the PL decay time is reported increasing the temperature, suggesting the thermal activation of a transfer process from non-radiative states. By the comparison of reflectivity and PL measurements we correlate the emission bands to the resonances in the reflectivity spectra, proving the high sample quality. Moreover, by local thermal heating with laser pulses we show that we can change the relative weight of bulk and nanocrystal emission, opening the route to a controllable modification of the film nanotexture.