Oligothiophene-based photovoltaic materials for organic solar cells: rise, plateau, and revival

Oligothiophene derivatives have been positioned as one of the most promising donor materials in cost-effectiveness and large-scale production of organic solar cells (OSCs). Oligothiophene donors have been popularized in the era of fullerenes but have not been successful as nonfullerene acceptors (NFAs). The recent report of over 15% power conversion efficiency (PCE) for OSCs has attracted research interest in these materials. Herein, the development of oligothiophene-based photovoltaic materials and their applications in OSCs are chronologically presented. The evolution of oligothiophene donors and milestone materials are highlighted and results on oligothiophene-based NFAs are included. To offer guidance and spur further development of oligothiophene-based photovoltaic materials, we propose a perspective on future trends in the molecular design and applications of oligothiophene donors/acceptors.