Triple Molecular Synergy-Driven Reconstruction of PEDOT:PSS Hole Transport Layer via Sodium Hydroxamate for Stable and Efficient Inverted Perovskite Solar Cells

Inverted p-i-n structured perovskite solar cells (PSCs) have been extensively studied due to their advantages of low cost, low-temperature film formation, and compatibility with tandem structures. However, the performance of corresponding PSCs remains unsatisfactory owing to disadvantages such as energy level mismatch and an unsatisfactory interface between the hole transport layer (HTL) and the perovskite. Here, sodium octyl hydroxamate (SOHA) as an additive is introduced into the HTL to improve the device performance, while a water exposure treatment is employed to effectively remove the extra impurities which generated after additive introduction. It can optimize the perovskite growth environment and effectively improves the quality of the perovskite thin film. It is demonstrated that the HTL/SOHA composite film enhances the conductivity and hole mobility of the HTL while simultaneously improving perovskite crystallinity and surface morphology. The fill factor (FF) and short-circuit current density (Jsc) are significantly enhanced. The optimized devices achieve an average power conversion efficiency (PCE) of 20.21%, representing a 16.8% enhancement compared to the control device (PCE = 17.31%).