Impact of CsPbI3 incorporation on the structural, optical, and electrical properties of mixed-halide perovskite solar cells

This study presents a novel approach to enhancing the performance of CsPbIBr₂ perovskite solar cells by incorporating 10% CsPbI₃ via spray coating. X-ray diffraction (XRD) confirms the α-cubic crystal structure, with improved crystallinity and increased crystallite size from 33.4 nm (pure) to 39.9 nm (modified), reducing dislocation line density (8.97 × 10¹⁴ to 6.28 × 10¹⁴ m⁻²). Optical analysis shows a bandgap reduction from 2.13 eV to 2.04 eV, enhancing light absorption and charge transport. Dielectric properties also improve, with the real dielectric constant increasing from 11.74 to 11.93. The modified perovskite film exhibits stronger PL intensity than the pure film, indicating reduced non-radiative recombination. Electrochemical impedance spectroscopy (EIS) indicates a significant reduction in charge transfer resistance (R_ct) from 103.27 Ω to 29.61 Ω, with increased recombination resistance (R_rec) from 5597.13 Ω to 5877.44 Ω, leading to superior charge transport. The modified perovskite solar cell exhibits superior performance, achieving an increased short-circuit current density (10.73 to 12.92 mA/cm²) and power conversion efficiency (10.48% to 12.91%) as confirmed by current density voltage (JV) measurement. Electrochemical impedance spectroscopy reveals reduced charge transfer resistance, improving electron mobility and suppressing recombination. These advancements highlight the potential of modified perovskites in high-efficiency photovoltaics.

Graphical Abstract

With the incorporation of CsPbI₃, the modified perovskite-based device showed the PCE upto 12.91%.