SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3628-3
The solution aggregation structures of conjugated polymers are pivotal in determining their film morphology and optoelectronic properties, yet the relationship between solution aggregation and device performance remains elusive in organic photodiode (OPD) systems. Herein, we introduce the first examination of solution aggregation structures of all-polymer OPD blends, with a focus on how molecular entanglement modulates aggregation behavior and subsequent photodiode performance of low-cost poly(3-pentylthiophene). Using small-angle neutron scattering and freeze-dried imaging, we provide a comprehensive analysis of the solution-state aggregation behavior of poly(3-pentylthiophene) and its evolution in the blend, revealing profound impacts on film morphology and device performance. With finely optimized aggregation, the resulting all-polymer OPD achieves a record-high specific detectivity of ~4×10^13 Jones at zero bias, outperforming all bulk heterojunction (BHJ)-type self-powered OPDs reported to date. This device also demonstrates remarkable thermal stability, with negligible performance degradation after over 800 h of thermal annealing at 85 °C. Furthermore, the self-powered OPD exhibits excellent performance across a broad spectral range, enabling its application in both water quality monitoring and biosensing. This work offers new insights into the solution aggregation behavior of conjugated polymers in OPDs and highlights the importance of resolving solution aggregation in optimizing device function.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4060-5
Organic solar cells (OSCs) offer unique advantages for wearable electronics due to their light weight and mechanical flexibility. However, achieving both high optoelectronic performance and mechanical robustness in organic semiconductors remains challenging, compromising the efficiency and durability of stretchable OSCs. Here, we report a cross-linked conjugated polyelectrolyte (CPE)-polyoxometalate (POM) anode interlayer (AIL), PTN-POM, constructed via strong electrostatic interactions between ammonium groups and POM. The PTN-POM film exhibits an electrical conductivity of 3.30×10−3 S/m and high stretchability, significantly outperforming the classic PEDOT:PSS AIL in mechanical strength. Binary OSCs modified with PTN-POM achieve a power conversion efficiency (PCE) of 19.59%, the highest reported for OSCs using a cross-linked AIL. Notably, PTN-POM enables fabrication of water-proof OSCs that show no performance degradation after underwater storage for 42 days. Furthermore, stretchable OSCs incorporating PTN-POM demonstrate enhanced mechanical robustness, retaining 81% of initial PCE under a large tensile strain of 50%. This work significantly enhances the photovoltaic, waterproof, and mechanical properties of OSCs, advancing their potential for wearable photovoltaics.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3406-2
Intrinsically stretchable organic solar cells (IS-OSCs) are critical for wearable and portable power, yet state-of-the-art PM6-based active layers exhibit fracture strains below 8% and high elastic modulus due to rigid conjugated backbones. This tutorial review systematically examines strategies to enhance mechanical resilience while preserving photovoltaic performance. We analyze third-component incorporation—guest polymer donors/acceptors and insulating polymers—as a primary route to improve stretchability, with specific examples achieving crack-onset strain (COS) exceeding 40% via flexible spacer-block multi-component copolymerized donors (Energy Environ Sci, 2024, 17: 9359–9374). Structural design of PM6 aimed at reducing backbone rigidity is discussed, including non-covalent interactions with polyvinyl chloride that yield excellent mechanical properties and stability (Angew Chem Int Ed, 2023, 62: e202312357). Predictive models for mechanical properties are summarized, encompassing modulus, COS, and fracture strain. Recent advances report mechanically robust OSCs with 19% efficiency (Adv Mater, 2024, 36: 2312805) and certified flexible organic photovoltaics beyond 19% via synergistic multimodal energy dissipation (Adv Mater, 2025, 37: 2411989). Insulating polymer-mediated stability and performance are shown to depend on molecular weight (Adv Funct Mater, 2024, 34: 2408340). The review concludes with future challenges and perspectives for stretchy OSCs, emphasizing the trade-off between efficiency and mechanical robustness.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3429-x
Organic electrochemical transistors (OECTs) offer high transconductance and biocompatibility for wearable biosensing, yet their deployment in conformal, long-term electrophysiological monitoring is constrained by the mechanical mismatch and leakage of liquid electrolytes. This work introduces a double-network stretchable gel electrolyte that simultaneously achieves a Young’s modulus of 114 kPa and an elongation at break of 640%, matching soft biological tissues while enabling photopatterning for high-density device arrays. Integrating this electrolyte with a stretchable PEDOT:PSS channel yields solid-state OECTs with a volumetric capacitance–mobility product ([μC*]) of 317.71 ± 11.61 F cm⁻¹ V⁻¹ s⁻¹ and an average transconductance of 7.89 mS across uniform arrays. Under 50% tensile strain, the devices maintain stable electrical performance and acquire electrocardiogram signals with a signal-to-noise ratio of approximately 30 dB. The fabrication route is low-cost and compatible with solution processing, addressing the trade-off between ionic conductivity and mechanical robustness that has hindered previous gel electrolytes. These results demonstrate a viable pathway for stretchable, solid-state OECTs in ambulatory cardiac monitoring and high-resolution biointerfaces, where mechanical compliance and signal fidelity are paramount.