Improving Efficiency and Light Stability of Perovskite Solar Cells by Incorporating YVO₄:Eu₃⁺, Bi₃⁺ Nanophosphor into the Mesoporous TiO₂ Layer

Even though a high power conversion efficiency (PCE) of 22.1% is achieved in the perovskite solar cells (PSCs), the ultraviolet (UV) light stability in PSCs is still a challenge that needs to be overcome before their actual application in an outdoor environment. In this work, we incorporated the YVO4:Eu3+, Bi3+ luminescent down-shifting (LDS) material into the mesoporous TiO2. The YVO4:Eu3+, Bi3+ would convert the high UV photons into the low energy visible photons (red light) and improve the utilization of UV light in PSCs, which results in PCE enhancement and UV light stability improvement in PSCs. By controlling the YVO4:Eu3+, Bi3+ concentrations, an optimized PCE of 17.9% is obtained, which shows an improvement of 9.8% compared with the bare device. More importantly, the device based on the m-TiO2/YVO4:Eu3+, Bi3+ layer has distinguished stability under UV light irradiation, which could maintain 70% initial efficiency after 60 h of UV irradiation.