Cahyorini Kusumawardani, Jaslin Ikhsan, Kun Sri Budiasih, Herlambang Nugroho, Asri Widowati
The CH3 NH3 PbI3-x Brx have been successfully synthesized under uncontrolled humidity using two-step spin coating method continued by Ostwald ripening (OR) treatment. The incorporation of Br in the CH3 NH3 PbI3 was done by diluting the previously formed of CH3 NH3 PbI3 with various concentration of CH3 NH3 Br (MABr) solution. XRD analysis confirmed the formation of a tetragonal perovskite phase with reduced lattice parameters as the bromide concentration increased, indicating successful I- to Br- substitution. SEM and EDX characterization showed that moderate bromide incorporation (30-40 mg/mL) produced dense, uniform grains and homogeneous halide distribution, while excessive MABr led to non-uniform morphology and halide segregation, particularly under humid conditions. Optical analysis revealed a gradual blue shift in the absorption edge, consistent with band gap widening due to lattice contraction. The photovoltaic performance measurements demonstrated that higher MABr concentrations caused decreased current density and fill factor, resulting from excessive bromide content and defect formation. These findings showed that controlled bromide incorporation through Ostwald ripening with MABr concentration of 20 mg/mL effectively enhances the structural quality, film stability, and photovoltaic performance of CH3 NH3 PbI3-x Br3 perovskite solar cells under humid environments. © 2026, Magister Program of Material Sciences, Graduate School of Sriwijaya University. All rights reserved.
Department of Chemistry Education, Universitas Negeri Yogyakarta, Yogyakarta, 55281, Indonesia; Department of Science Education, Universitas Negeri Yogyakarta, Yogyakarta, 55281, Indonesia
