Organometallic Complexes as Non-Fullerene Acceptors: Towards High-Performance Organic Solar Cells

Abstract

Recent rapid advancements in organic solar cells (OSCs) have transformed the field of photovoltaics. Although donor materials are extensively utilized and studied for OSCs, the fast progress in the progress of non-fullerene acceptors (NFAs) has grabbed the widespread attention. Among various classes of reported materials, the use of organometallic complexes (OMCs) as promising donors is well known, however their use as efficient NFA has recently emerged. The recent development in OMCs as NFAs has indicated their potential to reach high efficiency owing to their structural flexibility and electron-rich metal centers. This review summarizes the progress and development in the NFAs based on OMCs with various metals such as iron (Fe), iridium (Ir), platinum (Pt), and others. It also highlights molecular design principles, optoelectronic properties, structure-property relationships, and photovoltaic performances, along with comparisons between ferrocene-, iridium-, platinumand porphyrin-based NFAs for better understanding. The progress in the field of OMC-based NFAs has shown PCEs up to 10.84% in binary and 19.24% in ternary blends indicated their potential as next-generation photoactive materials. Finally, conclusions and future opportunities are outlined to guide further research development.