Minimizing energy losses in organic solar cells: mechanistic insights, material design, and morphological control

Abstract

Organic solar cells (OSCs) exhibit promising potential for low-cost photovoltaic applications but suffer from high energy losses (E_loss) that critically limit their open-circuit voltage and power conversion efficiency. To address this challenge, this review first outlines the mechanistic origins of E_loss, emphasizing exciton dissociation barriers, charge-transfer state energetics, and recombination pathways, supported by quantitative characterization methodologies. Building on this foundation, material design strategies are analyzed, where molecular synthesis targeting backbone, side-chain, and terminal group optimization alongside ternary blending collectively modulates energy-level alignments to minimize driving-force offsets. Concurrently, morphological control approaches are systematically evaluated, demonstrating that precise regulation of phase separation, crystallinity, and molecular orientation effectively suppresses recombination losses and enhances charge transport. By integrating these advances, this work establishes a unified framework for energy loss minimization, providing critical insights for developing high-performance OSCs.