Single-Component Organic Solar Cells with over 14% Efficiency.

Single-component organic solar cells (SCOSCs), with covalently linked donor and acceptor, attract considerable attention for their improved thermodynamic stability over traditional bulk heterojunction (BHJ) organic solar cells. Despite the significant potential of SCOSCs, their efficiency has consistently trailed behind that of their BHJ counterparts for years, primarily due to challenges including rapid charge recombination, intricate phase separation, and substantial energy loss. Herein, this work represents a significant milestone in the advancement of SCOSCs based on a single component of PBDB-T--PYT, achieving both high efficiency (14.64%) and low energy loss (0.563 eV) through the combined use of thermal and solvent annealing. Optimized devices exhibit not only higher charge carrier mobilities but also a more balanced distribution, facilitating efficient transport and collection of photogenerated charge carriers by individual electrodes, while also demonstrating lower nonradiative recombination losses, thus contributing to superior optoelectronic performance and stability.