An innovative strategic route to the green synthesis of CsPbBr3 films on rigid and flexible substrates

Recently, the all-inorganic halide perovskites have attracted great attention due to their unique optical prop-erties, which make them appealing, if available in form of films, for application in different devices, such as photodetectors, catalysis, or energy conversion systems like solar cells.We report a facile, one-step approach using the beta-diketonate metal -organic precursors, [Pb(hfa)2diglyme]2 and Cs(hfa) to obtain CsPbBr3 halide perovskite microcrystals. The CsPbBr3 suspension in ethanol has been deposited on a wide range of rigid and flexible substrates by spray-coating. The entire process has been carried out at room temperature and at atmospheric pressure in air. The X-ray diffraction (XRD) and Energy Dispersive X-ray analysis (EDX) confirmed the formation of pure stoichiometric CsPbBr3 phase films, while the field-emission scanning electron microscopy (FE-SEM) indicates the growth of a compact and homogeneous layer independently on the substrate nature. The optical energy band-gap (Eg) of CsPbBr3 films on quartz, estimated through the Tauc equation, is equal to 2.31 eV. Steady state Photoluminescence (PL), Time Resolved Photo-luminescence (TRPL), and Photoluminescence Quantum Yield (PLQY) investigations have been carried out confirming the quality of the films in agreement with literature. This synthetic approach allows the fabrication of perovskite CsPbBr3 films on a variety of substrates, as well as providing a proof-of-concept method to extend this simple, practical, and versatile route for the production of mixed halide perovskite phases.