High-efficiency organic solar cells prepared using a halogen-free solution process
Febrian Tri Adhi Wibowo, Narra Vamsi Krishna, Septy Sinaga, SeungJe Lee, Wisnu Tantyo Hadmojo, Young Rag, Sung‐Yeon Jang
Abstract
Although the power conversion efficiency (PCE) of organic photovoltaic (OPV) devices has recently improved to more than 16%, halogenated solution processes are typically employed to obtain optimal performance. However, halogenated processing is harmful to health and the environment, which can be a significant obstacle to commercialization. Therefore, development of active materials processable under halogen-free conditions is of great importance in this field. In this study, a 16.04% OPV device, processed under halogen-free conditions, is developed by employing a new active-blend system, PBDTTPD-HT:BTP-2F-BO. It is highly soluble in halogen-free solvents, forming a preferential bulk-heterojunction morphology. The PBDTTPD-HT:BTP-2F-BO device achieves a PCE comparable with current state-of-the-art devices based on PBDB-TF:BTP-4F (also known as PM6:Y6) using a conventional halogenated process (16.40% versus 16.33%). Furthermore, it demonstrates a significantly higher PCE than the PBDB-TF:BTP-4F device with a halogen-free process (16.04% versus 9.70%).