Modulating buried interface with a natural chemical VB2 for TiO2-based planar perovskite solar cells

Abstract

Interfacial engineering, especially the modulation of the buried interface, has a strong impact on the photovoltaic performance of perovskite solar cells (PSCs). In this study, a natural chemical, riboflavin (VB₂), was introduced to modify the TiO₂/perovskite interface in planar PSCs. As a result, oxygen defects in TiO₂ were passivated, and the quality of the perovskite film, together with the energy level arrangement, was optimized. Finally, PSCs modified with VB₂ showed a significant increase in power conversion efficiency (PCE) from 19.2% to 21.50%. Additionally, PSCs modified with VB₂ exhibited better long-term stability by maintaining 75.8% of their original PCE after 700 hours of aging at a relative humidity (RH) of 30% ± 5% and at room temperature.