Progress and prospects of thick-film organic solar cells

With the continuous improvements in the performances of laboratory-scale organic solar cells (OSCs), the development of efficient OSCs with thick active layers compatible with large-area printing processes is an inevitable requirement for commercialization in this field. Although high power conversion efficiencies (PCEs) of over 17% have been achieved using non-fullerene acceptors (NFAs) in thin-film OSCs, the performance of thick-film OSCs lag behind those of thin-film OSCs owing to the increased probability of charge recombination in thick film. To realize a transition from the laboratory-scale to industrial high-throughput manufacturing, the foremost aspect is to develop highly efficient photoactive materials that are capable of exhibiting attractive performances under a thick film with an optimal morphology for charge generation and transport. In this review, we summarize the developments of materials used for efficient thick-film OSCs over the last decades and present the remaining challenges for realizing the practical application of OSCs.