SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4316-0
The rapid development of small molecule acceptors (SMAs) has enabled organic photovoltaics (OPVs) to achieve power conversion efficiencies exceeding 21%. Structural asymmetry has emerged as a particularly effective approach for boosting acceptor performance. This review provides a comprehensive overview of asymmetric SMAs from the molecular scale to the nanoscale and macroscale. The main text is organized into four sections: molecular design strategies for structural asymmetry, crystal structure evolution from symmetry breaking, morphological characteristics revealed by advanced characterization techniques, and energy loss mechanisms involving asymmetric SMAs. At the molecular scale, asymmetry enables precise modulation of dipole moments and intermolecular interactions, directly affecting crystalline packing and charge-transport networks. At the nanoscale, it further regulates domain purity, phase continuity, and molecular orientation. Asymmetric designs can also help mitigate non-radiative voltage loss through modulation of charge-transfer state energetics. Overall, asymmetric molecular design introduces additional structural and electronic tunability, offering new opportunities for overcoming the trade-offs that limit OPV performance. Finally, we discuss ongoing challenges and outline future perspectives to guide continued development and innovation in asymmetric SMA design.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3451-2
Visual aesthetics is a key metric of semi-transparent organic photovoltaics (ST-OPVs) for building-integrated solar windows, yet previous studies have primarily focused on the compromise between efficiency and transparency. This work addresses the overlooked aspect of full visual aesthetic control, particularly the bidirectional reflected color for architectural harmony, via designing ST-OPVs with double-sided ultra-thin Ag/TeO2 transparent electrodes. This design facilitates full-spectrum color tunability covering the whole standard color gamut of CIE coordinates on both surfaces, achieved simply by adjusting layer thicknesses. The resulting devices exhibit neutral transparency (16.6%–27.0% average visible transmittance) and competitive power conversion efficiencies (8.1%–9.2%). Additionally, the devices demonstrate strong flexibility, with flexibility-adaptive coloration and curvature-enhanced aesthetics. This work presents an ST-OPV design featuring full visual aesthetics and considerable performance, paving the way for commercialization of organic solar windows for building and vehicle integration.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3980-y
Organic solar cells (OSCs) have achieved power conversion efficiencies (PCEs) exceeding 20% in laboratory-scale devices, yet challenges persist in developing cost-effective charge-transporting materials (CTMs) that ensure high performance and long-term stability. Conventional organic CTMs such as PEDOT:PSS and PDINN suffer from thermal instability due to molecular diffusion and phase segregation. Solution-processed metal oxides (MOs) offer excellent stability and cost-effectiveness but are plagued by surface defects, particularly hydroxyl groups, which act as recombination centers and photocatalytic sites, degrading device interfaces. Here, we develop an organic-inorganic hybrid strategy to homogeneously passivate solution-processible semiconducting MOs. By first synthesizing MOs rich in surface hydroxyl groups and then introducing organic molecules, we achieve chemically homogeneous passivation that mitigates surface defects. This approach enables favorable interfacial energy level alignment, enhanced charge extraction, and tunable surface energy. Employing these passivated MOs as electron transport layers (ZnO) and hole transport layers (NiOx), we achieve a champion PCE of 20.22% for all-MO CTM-based OSCs, the highest reported to date. Scalability is demonstrated via ambient blade-coating, yielding 18.33% PCE for large-area cells (1.44 cm2) and 16.03% for modules (20.05 cm2), with material costs estimated at only 4% of organic counterparts. Furthermore, devices exhibit outstanding stability, retaining over 80% of initial PCE after 1300 h of maximum power point tracking and over 1000 h of thermal annealing at 85°C. This work establishes a new benchmark for cost-effective, high-performance organic photovoltaics.