Mechanical Stability in Stretchable Organic Photovoltaics

Stretchable organic photovoltaics combine the lightweight, solution-processable nature of organic semiconductors with mechanical compliance, enabling power generation on curved and deformable surfaces. Achieving robust mechanical stability under cyclic deformation and high tensile strains demands careful material and device engineering. Key strategies include the redistribution of strain within the active layer, the design of intrinsically stretchable electrodes and interlayers, and the optimisation of polymer acceptor and donor architectures. Improved interfacial adhesion and morphological control minimise crack initiation and propagation, while dynamic bonding interactions and flexible spacer units confer enhanced fracture resistance. Characterisation methods such as tensile testing, cyclic strain evaluation and nanoindentation inform the relationship between molecular structure, film mechanics and photovoltaic performance. Collectively, these advances are paving the way for wearable energy harvesters, conformable sensor networks and large‐area, deformable solar panels for next‐generation electronics.

Research from Nature Portfolio

Recent studies have demonstrated that strain redistribution within the active layer can substantially enhance stretchability and durability. One report introduced a highly stretchable electrode by incorporating ionically conductive additives into a conductive polymer, achieving more than 80 % of the original power conversion efficiency at 50 % tensile strain and retaining 95 % efficiency after 100 strain cycles. In parallel, another investigation employed dynamic hydrogen-bonding moieties in the acceptor side chains, which not only delivered a binary device power conversion efficiency approaching 20 % but also conferred greater mechanical robustness and thermal stability under repeated deformation, all processed from non-halogenated solvents.

Mechanical Stability in Stretchable Organic Photovoltaics publication trend

The graph below shows the total number of articles in mechanical stability in stretchable organic photovoltaics across all publications each year (not limited to Nature Index journals).

Technical terms

Bulk heterojunction (BHJ): an interpenetrating network of donor and acceptor materials in the active layer of organic solar cells to facilitate efficient charge separation and transport.

Power conversion efficiency (PCE): the ratio of electrical power output to incident light power, expressed as a percentage to assess photovoltaic performance.

Tensile strain: the relative deformation experienced by a material when stretched, defined as the change in length divided by the original length.

PEDOT:PSS: a blend of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate used as a transparent, conductive and stretchable electrode in organic electronics.

Crack onset strain (COS): the tensile strain at which the first mechanical fracture or crack appears in a thin film under stress, indicating the onset of mechanical failure.

References

1. Intrinsically stretchable organic photovoltaics by redistributing strain to PEDOT:PSS with enhanced stretchability and interfacial adhesion. Nature Communications (2024).
2. Sequentially regular polymer acceptors featuring flexible spacers for high-performance and mechanically robust all-polymer solar cells. Energy & Environmental Science (2022).
3. Multi-scale mechanical properties of bulk-heterojunction films in polymer solar cells. npj Flexible Electronics (2023).
4. Dynamic hydrogen-bonding enables high-performance and mechanically robust organic solar cells processed with non-halogenated solvent. Nature Communications (2025).