Photoelectrochemical Applications of Organic Semiconductor Systems

Organic semiconductors offer a unique combination of tunable optoelectronic properties, low-cost solution processability and the potential for large‐area manufacturing, making them attractive for photoelectrochemical (PEC) fuel generation and chemical synthesis. In PEC cells, organic photoactive layers harvest sunlight to drive oxidation or reduction reactions at the semiconductor–electrolyte interface. Key applications include solar water splitting to produce hydrogen, photocathodic oxygen reduction to generate hydrogen peroxide, and bias‐free conversion of carbon dioxide or biomass‐derived substrates. Progress has been driven by donor–acceptor bulk heterojunction (BHJ) architectures that enhance light absorption and charge separation, and by interfacial engineering strategies that protect photoactive layers from aqueous degradation and suppress charge recombination. Recent developments have addressed longstanding challenges of operational stability, interfacial losses and limited absorption bandwidth by integrating protective overlayers, embedding earth‐abundant catalysts and extending light harvesting into the near‐infrared. Advances in device structuring, including nanostructured electrodes and polymer‐electrolyte interphases, have elucidated charge transport and recombination processes, while emerging co‐design approaches seek to optimise both semiconductor chemistry and catalytic environment. These innovations pave the way towards scalable, low‐cost PEC systems for clean fuel and chemical production under practical operating conditions.

Research from Nature Portfolio

Recent studies have demonstrated that integrating BHJ organic photoactive layers with graphite‐supported water‐oxidation catalysts can overcome aqueous instability and interfacial recombination. In one report, polymer donor and non‐fullerene acceptor blends protected by a graphite sheet functionalised with a NiFeOOH catalyst achieved photocurrent densities exceeding 25 mA cm⁻² at 1.23 V versus the reversible hydrogen electrode, with days‐long operational stability. Monolithic tandem anodes combining two complementary BHJ systems yielded an unassisted solar‐to‐hydrogen efficiency of 5 %, illustrating the feasibility of low‐cost organic materials for direct solar water splitting under bias‐free conditions.

Photoelectrochemical Applications of Organic Semiconductor Systems publication trend

The graph below shows the total number of articles in photoelectrochemical applications of organic semiconductor systems across all publications each year (not limited to Nature Index journals).

Technical terms

Organic semiconductor: A class of carbon‐based materials in which conjugated molecular or polymeric structures support mobile charge carriers under illumination or applied bias.

Photoelectrochemical cell: A device that combines light absorption by a semiconductor with electrochemical reactions at its surface to convert solar energy into chemical fuels or value‐added products.

Bulk heterojunction (BHJ): A nanoscale interpenetrating network of electron‐donor and electron‐acceptor materials designed to maximise charge‐separation efficiency and light absorption.

Photoanode: The positively biased electrode in a PEC cell where photoinduced oxidation reactions take place, often for water oxidation or organic substrate oxidation.

Photocurrent density: The current generated per unit electrode area under illumination, typically measured in milliamps per square centimetre (mA cm⁻²).

References

1. Enhanced solar water oxidation and unassisted water splitting using graphite-protected bulk heterojunction organic photoactive layers. Nature Energy (2025).
2. Long‐Lived Charges in Y6:PM6 Bulk‐Heterojunction Photoanodes with a Polymer Overlayer Improve Photoelectrocatalytic Performance. Advanced Energy Materials (2023).
3. Soft Materials for Photoelectrochemical Fuel Production. ACS Energy Letters (2023).
4. A Dual Functional Polymer Interlayer Enables Near‐Infrared Absorbing Organic Photoanodes for Solar Water Oxidation. Advanced Energy Materials (2022).