Performance and stability improvements in MAPbI3 perovskite photovoltaics with CsPbI3 quantum dots

This study presents a novel heterojunction design for perovskite photovoltaic cells (PPVCs) that integrates CsPbI3 quantum dots with MAPbI(3). Preliminary modeling indicates that the PPVCs achieved a notable efficiency of 27.04% with a fill factor (FF) of 81.60%, a short- circuit current density (Jsc) of 28.15 mA/cm2, and an open- circuit voltage (Voc) of 1.18 V when employing a light-sensitive layer with a thickness of 350 nm. This efficiency significantly exceeds that of current technologies, which typically ranges from 14.5% to 22.52%. The integration of CsPbI3 enhances both the light absorption and charge carrier mobility, while also improving the thermal and chemical stability. This stability is achieved through the hydrophobic nature and structural integrity of CsPbI3, which mitigates degradation under environmental stressors, such as moisture and heat. The study also examines various photosensitive layers, including CsPbI3/MAPbI3, CsPbI3, MAPbI3, MAPbCl3, and CsPbBr3, to determine the optimal power conversion efficiency (PCE) of the proposed device. Key factors such as series resistance (Rs) and shunt resistance (Rsh) are critical in optimizing the PCE; high Rs can impede current flow and reduce the fill factor, while a low Rsh can lead to leakage currents that diminish the voltage output. The optimal doping density is essential for maximizing the charge charge-carrier concentration, which directly influences the overall efficiency. Furthermore, the impact of varying the metal work functions has been investigated. It has been observed that Pt-O, with a work function of approximately 4.9 eV, and C-Cu, exhibiting a work function of approximately around 5 eV, present viable alternatives to the traditionally utilized and more costly gold (Au), which has a work function of approximately 5.1 eV. This study elucidates the significant potential of this novel heterojunction design and material synergy, potentially facilitating more efficient and durable solar energy solutions, and advancing the commercialization of perovskite solar technologies.