Inorganic CsPbI3 perovskite has garnered significant attention in photovoltaic applications due to its exceptional thermal stability and optoelectronic properties. However, severe energy losses in CsPbI3 perovskite solar cells, stemming from non-radiative interface recombination and poor carrier transport, have critically hindered their photovoltaic performance and operational stability. Addressing this challenge, a research team led by Xiaoliang Zhang from Beihang University has published a study titled “Fluoridation-assisted Interfacial Dipole for CsPbI3 Perovskite Solar Cells with over 22% Efficiency” in the journal Angewandte Chemie International Edition. The study introduces an interfacial dipole modulation method for CsPbI3 perovskite solar cells, utilizing azetidinium chloride (Az) and its fluorinated derivative, 3,3-difluoroazetidinium chloride (DFAz), to regulate the interfacial properties of perovskite solar cells and mitigate energy losses.
Systematic theoretical calculations and experimental investigations reveal that fluoridation-assisted ammonium molecules form stronger interactions with the perovskite, thereby adjusting the dipole alignment of the perovskite surface layer. This modification simultaneously enhances the passivation effects and energy level alignment between the perovskite layer and the hole-transporting layer, suppressing interfacial recombination. Additionally, the coordination bonding between the ammonium molecules and the hole-transporting layer provides an auxiliary carrier transport pathway, facilitating charge transfer at the heterojunction interface. As a result, the CsPbI3 perovskite solar cells achieve a remarkable efficiency of 22.05%. This research establishes key principles for interfacial engineering in high-performance solar cells, offering a strategy to minimize energy losses and advance photovoltaic technology.
