Due to the advantages of efficient carrier transport, the implementation of fibrous molecular frameworks in organic solar cells (OSCs) is highly encouraged. However, this is mainly achieved through the chemical structure design of photovoltaic semiconductors. Tao Wang et al. from Wuhan University of Technology adjusted the intermolecular interactions between a series of BDT type polymer donors (PM6, D18, PBDB-T, PTB7 Th) using three alkoxythiophene additives T-2OMe, T-OEH, and T-2OEH during solution casting to self-assemble into nanofibers.
X-ray technology and molecular dynamics simulations have shown that alkoxythiophene with (2-ethylhexyl) oxy (- OEH) chains can attach to the 2-ethylhexyl (EH) chains of these polymer donors and promote their self-assembly into one-dimensional nanofibers in their clean films and photovoltaic mixtures with L8-BO.
By using these raw fiber polymer donors to construct a pseudo bulk heterojunction (P-BHJ) OSC through layer by layer deposition, device performance has generally improved, with PCE increasing from 18.2% to 19.2% (certified as 18.96%) and from 17.9% to 17.9%. The PM6/L8-BO and D18/L8-BO devices range from% to 18.7%, respectively. This work provides a physical method to promote fiber like charge transfer channels for efficient photovoltaic power generation.
Liu, C., Fu, Y., Zhou, J., Wang, L., Guo, C., Cheng, J., Sun, W., Chen, C., Zhou, J., Liu, D., Li, W., Wang, T., Alkoxythiophene Directed Fibrillization of Polymer Donor for Efficient Organic Solar Cells. Adv. Mater. 2023, 2308608.
https://doi.org/10.1002/adma.202308608