The influence of aluminum doping on the structural, optical, and electrical performance of CsPbIBr2 perovskite solar cell

Abstract

This study aims to tackle the persistent issues in thin-film perovskite solar cells, focusing on stability, efficiency, and performance consistency. The motivation behind this research lies in the search of material which enhanced crystalline quality, and improved charge carrier dynamics to advance the current state of thin-film and device technology. By introducing aluminum (Al) doping in CsPbIBr2 perovskite films. X-ray diffraction confirms a cubic perovskite phase, with Al doping resulting in reduced FWHM values and increased crystal size, indicating enhanced crystalline quality. Ultraviolet (UV)-visible spectroscopy reveals reduced bandgap energy from 2.09 to 2.01 eV with Al doping, promoting better photon absorption and carrier mobility. Photoluminescence (PL) measurements also show that the Al-doped material has a stronger PL peak intensity compared to the pure material. The ion replacement of Pb⁺² with Al⁺³ causes the lifetime of the CsPbIBr₂ film to increase from 2.87 to 3.39 ns, according to time-resolved PL measurements. The longer lifetime of the Al-doped device indicates that the carrier lifetime is extended due to a decrease in the trap densities. The study revealed that the dark-current density-voltage characteristics of the device significantly improved the performance of photovoltaic cells These electrical parameters efficiency, open circuit voltage (V_oc), short circuit current density (J_sc), and fill factor (FF) has increased from 9.05%, 1.14 V, 11.27 mA-cm⁻², and 0.86 in the pure sample to 10.31%, 1.16 V, 12.36 mA-cm⁻², and 0.90 in the Al-doped sample respectively. This improvement could be attributed to the reduced trap densities and improved charge carrier dynamics. This approach is novel as it leverages ion replacement to stabilize the perovskite structure while simultaneously enhancing its photovoltaic performance of solar cell.

Graphical Abstract