All-Inorganic CsPbBr ₃ Perovskite Films via KBr/KCl Electrochemical Doping for Enhanced Optoelectronic Properties

All-inorganic CsPbBr3 perovskite films (band gap: 2.33 eV) were fabricated via a two-step electrochemical deposition (ECD) approach with controlled alkali halide codoping (KBr/KCl). Structural and morphological analyses (X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM)) show that 0.5 mg/mL KBr doping suppresses CsPb2Br5 formation, refines the grain size, and smooths film surfaces, reducing the charge-transfer resistance and extending the carrier lifetime from 3 to 8.3 ns. Compared to the undoped control, these changes deliver more than a 2-fold improvement in power conversion efficiency (PCE), driven by enhanced short-circuit current (JSC) and open-circuit voltage (VOC). KCl doping at 0.3 mg/mL concentration reduces the defect density by about 23% and yields 50% efficiency improvement. These findings show that targeted doping during electrochemical deposition can tune defect-phase interactions in CsPbBr3 perovskite and offers a scalable way to optimize its device performance.