Surface oxygen vacancy regulation via Li-doped in MOF-derived mesoporous TiO2 for printable mesoscopic perovskite solar cells

Li-doped mesoporous TiO 2 derived from Ti-MOFs is employed to regulate oxygen vacancies . Li doping passivates oxygen vacancies and decreases the interface surface energy on the TiO 2 surface for enhanced device performance. Finally, carbon-based printable mesoscopic PSCs achieved 18.07 % efficiency and improved long-term stability. • Li doped TiO 2 passivates surface oxygen vacancy defects and improvs its conductivity. • Li doped enhances the energy level alignment between TiO 2 and perovskite, and accelerates charge extraction. • The optimized PM-PSC achieved a champion PCE of 18.07 % and excellent long-term stability. The mesoporous TiO 2 displays low conductivity and abundant oxygen vacancies (OVs) defects, leading to reduced carrier extraction and affecting the power conversion efficiency (PCE) of perovskite solar cells (PSCs). In this study, we investigate the electron transport layer of mesoporous TiO 2 derived from Ti-MOFs with Li-doped, employing a strategy to regulate the OVs on the TiO 2 surface to enhance device performance. Experimental results demonstrate that Li doping increases the conductivity of TiO 2 , improves the energy level alignment between the TiO 2 and perovskite interfaces, and alleviates the residual stress in the perovskite. Theoretical calculations indicate that Li doping can inhibit the formation of OVs, reduce the band gap of TiO 2 , and decrease the surface energy of the interface, thereby enhancing carrier extraction. Ultimately, carbon-based printable mesoscopic PSC by Li-doped achieved a champion PCE of 18.07 % and improved long-term stability.