Structural and Optical Characterization of Spin-Coated Perovskite MAPbI 3 – x Br x Nano-Needles

— The presented paper dals with perovskite MAPbI 3 – x Br x nano-needles synthesized on the glass substrates by the spin coating technic. X-ray patterns showed the formation of the tetragonal phase. The crystallite size was almost constant by increasing the Br concentration up to 25%. Optical measurements showed a linear increase of the energy band gap by increasing the Br concentration, leading to the blue shift of the absorption onset. Scanning electron microscopy images showed the formation of the needle-like shapes. The grain size evolution is explained basing on the current studies.