Additive engineering with RbCl for efficient carbon based perovskite solar cells

Carbon-based perovskite solar cells (C-PSCs) have emerged as promising candidates owing to their cost-effectiveness, high stability, and simplified fabrication process. However, challenges related to stability and performance variations stemming from film quality persist as significant barriers to their widespread adoption. To address these concerns, additive engineering has emerged as a promising strategy. In our study, we introduced an appropriate amount of RbCl into the perovskite thin film. Rubidium (Rb), characterized by its smaller ionic radius, was anticipated to enhance annealing conditions, facilitating the formation of the perovskite phase and reducing bulk defects within the film. Additionally, the presence of Cl⁻ ions was expected to delay perovskite nucleation, leading to improved film morphology and reduced defect formation at the buried interface. Our champion C-PSC achieved a remarkable power conversion efficiency (PCE) of 16.85%, surpassing the control C-PSC manufactured under identical conditions, which exhibited a PCE of only 14.61%. RbCl doping proved instrumental in promoting dense film growth, reducing bulk defects, and suppressing non-radiative recombination, thereby enhancing overall device performance. Furthermore, RbCl-doped C-PSCs demonstrated exceptional long-term stability and moisture resistance when exposed to ambient air. These findings contribute valuable insights into the development of efficient, environmentally friendly, and cost-effective C-PSCs, highlighting the potential of the additive engineering strategy for enhancing device performance and stability.