Stability and Performance of Organic Photovoltaics

Organic photovoltaics combine lightweight, flexible materials with the potential for low-cost, large-area energy conversion. Over the past decade, power conversion efficiencies have climbed above 19 %, yet the long-term operational stability of these devices remains a primary barrier to commercial deployment. Degradation pathways include photo-oxidation, morphological evolution and the formation of defect states that compromise charge generation, transport and collection. Advances in molecular design, interfacial engineering and predictive analytics are converging to address these challenges. By tailoring the chemical structure of donor and acceptor materials, optimising bulk heterojunction morphology and suppressing trap formation, researchers are now achieving devices that retain over 80 % of their initial performance after tens of thousands of hours under accelerated testing. These developments not only elucidate fundamental degradation mechanisms but also demonstrate routes to durable and efficient organic solar cells suitable for real-world applications.

Research from Nature Portfolio

Recent studies have shown that precise geometry design of tethered small-molecule acceptors can deliver both high efficiency and exceptional stability. By engineering thiophene-dicarboxylate spacers and core isomerism, researchers achieved polymer solar cells with efficiencies above 18 % and extrapolated lifetimes of more than 35 000 hours at elevated temperature. Investigations into side-group steric hindrance have demonstrated that non-fullerene acceptors bearing conjugated pendants enable xylene-processed devices to exceed 18 % efficiency while maintaining robust thermal and photo-stability, highlighting a clear structure–performance–stability relationship. Furthermore, in-depth analysis of device aging reveals that trap-induced transport resistance, arising from defect state formation in the active layer, is the dominant cause of voltage and fill-factor losses under thermal stress. Suppressing these traps offers a promising pathway to significantly extend organic photovoltaic lifetimes.

Stability and Performance of Organic Photovoltaics publication trend

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

Technical terms

Bulk heterojunction: An interpenetrating network of donor and acceptor materials forming the active layer in organic solar cells.

Non-fullerene acceptor (NFA): A class of electron-accepting molecules that replace fullerene derivatives to improve light absorption and stability.

Power conversion efficiency (PCE): The ratio of electrical power output to incident solar power input under standard test conditions.

Trap state: A defect or localized energy level in the semiconductor that captures charge carriers, reducing mobility and recombination losses.

Glass transition temperature (Tg): The temperature at which an amorphous polymer transitions from a rigid to a rubbery state, affecting morphological stability.

Fill factor (FF): A metric of the squareness of a photovoltaic current–voltage curve, reflecting series resistance and charge recombination.

References

1. Revealing processing stability landscape of organic solar cells with automated research platforms and machine learning. InfoMat (2024).
2. Geometry design of tethered small-molecule acceptor enables highly stable and efficient polymer solar cells. Nature Communications (2023).
3. Importance of structural hinderance in performance–stability equilibrium of organic photovoltaics. Nature Communications (2022).
4. Traps and transport resistance are the next frontiers for stable non-fullerene acceptor solar cells. Nature Communications (2022).
5. Unraveling the Microstructure‐Related Device Stability for Polymer Solar Cells Based on Nonfullerene Small‐Molecular Acceptors. Advanced Materials (2020).
6. The critical role of the donor polymer in the stability of high-performance non-fullerene acceptor organic solar cells. Joule (2023).