Polymer Solar Cell Performance Enhancement Techniques

Polymer solar cells have attracted intense interest as a pathway to low-cost, flexible and lightweight photovoltaic technologies. Key strategies to elevate their power conversion efficiency and operational stability encompass optimisation of the photoactive layer morphology, interfacial engineering of charge-selective layers, molecular design of donor and acceptor materials, and incorporation of advanced doping or additive protocols. Control of phase separation within bulk heterojunctions ensures balanced exciton dissociation and charge transport, while the introduction of tailored interlayers at the cathode or anode can tune work functions, suppress recombination and improve environmental robustness. Recent efforts also explore multifunctional additives that combine charge-blocking and sensing functions, as well as solvent and surface treatments that promote favourable crystallinity and wettability. Taken together, these approaches address both the intrinsic energetic losses and extrinsic degradation pathways that have historically limited polymer solar cell commercialisation, thereby paving the way for scalable, high-performance devices in renewable energy generation.

Research from Nature Portfolio

Recent studies have demonstrated that modification of conventional conductive polymers can yield high-performance interlayers. Low-work-function poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) modified with polyethylenimine transforms into an efficient electron transport layer, achieving nearly 8 % power conversion efficiency in inverted devices while markedly enhancing stability by neutralising acidity and reducing hygroscopicity. In parallel, surface-wetting control has emerged as a robust route to simultaneous efficiency and endurance gains. An interfacial layer based on ethoxylated polyethyleneimine functionalised with unsaturated fatty acids tailors hydrophobic and hydrophilic domains, delivering over 10 % efficiency in rigid cells and over 9 % in flexible counterparts, with retention of almost 88 % performance after extended air exposure without encapsulation.

Research from all publishers

A novel acid-sensitive organic molecule has been developed to serve dually as a cathode interlayer and environmental pH sensor. When integrated into high-efficiency PM6:Y6 solar cells, this additive raises power conversion efficiency by nearly 50 %, achieving over 15 % and demonstrating reversible performance recovery under alkaline treatment. Such multifunctional interlayers exemplify the trend towards devices that combine energy harvesting with real-time diagnostic capabilities. Concurrently, roll-to-roll compatible cathode interface layers based on naphthalene diimide cores with oligo(ethylene glycol) side chains have been reported. These non-ionic, alcohol-processable polymers reduce trap-assisted recombination, elevate built-in potential by about 80 mV and boost power conversion efficiency to 16 % in polymer systems, while also imparting improved photostability and enabling thicker films suitable for large-area manufacturing.

Polymer Solar Cell Performance Enhancement Techniques publication trend

The graph below shows the total number of articles in polymer solar cell performance enhancement techniques across all publications each year (not limited to Nature Index journals).

Technical terms

Bulk heterojunction: A nanoscale interpenetrating network of donor and acceptor materials within the active layer that facilitates exciton dissociation and charge transport.

Power conversion efficiency (PCE): The ratio of electrical power output from a solar cell to the incident light power.

Cathode interlayer (CIL): A thin film between the active layer and cathode that optimises electron extraction and blocks holes.

Electron transport layer (ETL): A selective layer that facilitates electron conduction to the electrode while preventing back-injection of holes.

Work function: The minimum energy required to remove an electron from a solid to a point immediately outside its surface.

Wettability: The ability of a liquid to maintain contact with a solid surface, influencing layer uniformity and interfacial adhesion.

References

1. Acidochromic organic photovoltaic integrated device. Chemical Engineering Journal (2023).
2. Low Work-function Poly(3,4-ethylenedioxylenethiophene): Poly(styrene sulfonate) as Electron-transport Layer for High-efficient and Stable Polymer Solar Cells. Scientific Reports (2015).
3. A Nonionic Alcohol Soluble Polymer Cathode Interlayer Enables Efficient Organic and Perovskite Solar Cells. Chemistry of Materials (2021).
4. Enhanced flexible optoelectronic devices by controlling the wettability of an organic bifacial interlayer. Communications Materials (2021).