Photovoltaic performance enhancement of phenyl-C61-butyric acid methyl ester-based perovskite solar cells by lithium

Perovskite-based solar cells have attracted a lot of notice throughout the last decade due to their unique features. Perovskite solar cells (PSCs) rely significantly on charge transport materials (CTMs) to operate properly. Therefore, choosing a suitable and affordable CTM is essential. PCBM is commonly employed as an electron transport layer (ETL) in perovskite solar cells. However, it has several issues, such as low electron mobility, difficulty in achieving high-quality film, and a considerable rate of recombination at the perovskite/PCBM interface. In this study, it has been demonstrated that adding Li to the PCBM improves the PV performance of PSCs. In comparison to an undoped layer, Li doping improved the electrical conductivity, surface morphology, and interface quality by reducing roughness. It was revealed that doping increased electron mobility. Additionally, as shown by space charge limited current (SCLC) and photoluminescence (PL) examinations, the trap density of the perovskite layer is reduced, preventing undesirable charge recombination which leads to better photovoltaic performance.