Non-Fullerene Organic Solar Cell Development

The shift from fullerene-derived to non-fullerene acceptors (NFAs) has transformed the landscape of organic photovoltaic research. By replacing spherical fullerene cages with tailor-made conjugated molecules, NFAs offer broader absorption across the visible and near-infrared regions, finely tunable energy levels and enhanced morphological stability. Early success with fused-ring acceptors demonstrated efficiencies approaching those of silicon devices, yet concerns over synthetic complexity and cost spurred exploration of simpler architectures. Non-fused and noncovalently fused designs have since emerged, leveraging strategic core selection, side-chain engineering and end-group modifications to optimise molecular planarity, intermolecular packing and charge transport. As a result, power conversion efficiencies (PCEs) have climbed beyond 15 per cent in single-junction cells, with tandem and ternary devices pushing performance higher by extending spectral coverage. Concurrent advances in film processing and device engineering have improved photochemical and thermal stability, opening pathways to flexible, large-area modules. These developments promise scalable, low-cost organic solar technologies suitable for off-grid power, portable electronics and building-integrated photovoltaics on a global scale.

Research from Nature Portfolio

Researchers have designed a fully non-fused acceptor based on a planar bithiophene core that assembles into a three-dimensional interpenetrated network. Devices incorporating this molecule achieved a record PCE of 15.2 per cent and maintained over 84 per cent of initial performance after 1,300 hours of simulated sunlight. In foundational work on simple non-fused aromatic acceptors, two-step synthesis from basic aromatic units yielded blends with PCEs of 10.3 per cent in single-junction and nearly 14.0 per cent in tandem cells, alongside exceptional film uniformity and long-term photostability. Complementary studies of noncovalently fused-ring acceptors have shown that sulphur–oxygen interactions lock a ladder-like core, broadening near-infrared absorption and reducing synthetic steps. Optimised devices reached 13.2 per cent efficiency while exhibiting low non-radiative energy losses.

Non-Fullerene Organic Solar Cell Development publication trend

The graph below shows the total number of articles in non-fullerene organic solar cell development across all publications each year (not limited to Nature Index journals).

Technical terms

Non-fullerene acceptor (NFA): An organic electron-accepting molecule that replaces fullerene derivatives in bulk heterojunction solar cells, enabling customisable electronic and optical properties.

Fused-ring structure: A rigid, planar arrangement of aromatic rings sharing adjacent carbon atoms, which promotes strong π–π stacking and efficient charge transport.

Power conversion efficiency (PCE): The proportion of incident solar energy converted to electrical power by a photovoltaic device, expressed as a percentage.

π–π stacking: Attractive noncovalent interactions between overlapping aromatic systems in adjacent molecules, enhancing charge carrier mobility in thin films.

Bulk heterojunction: A nanoscale blend of donor and acceptor materials in a single active layer, forming interpenetrating networks for effective exciton dissociation and charge collection.

References

1. Simple non-fused electron acceptors for efficient and stable organic solar cells. Nature Communications (2019).
2. Noncovalently fused-ring electron acceptors with near-infrared absorption for high-performance organic solar cells. Nature Communications (2019).
3. Completely non-fused electron acceptor with 3D-interpenetrated crystalline structure enables efficient and stable organic solar cell. Nature Communications (2021).
4. Recent progress in low‐cost noncovalently fused‐ring electron acceptors for organic solar cells. Aggregate (2022).
5. A–D–A'–D–A type nonfused ring electron acceptors for efficient organic solar cells via synergistic molecular packing and orientation control. Aggregate (2024).
6. Highly efficient and stable binary and ternary organic solar cells using polymerized nonfused ring electron acceptors. National Science Review (2024).