Crosslinked Polymer Photovoltaic Systems

Crosslinked polymer photovoltaic systems harness the robust chemical bonding between polymer chains to stabilise the active layer morphology and enhance device longevity. By introducing multifunctional crosslinkers—often small molecules bearing reactive azide or epoxy groups—into donor–acceptor blends, researchers establish an insoluble network that resists thermal and solvent-induced phase separation. This network retains optimal nanoscale interpenetration of polymer donor and acceptor domains, ensuring efficient charge generation and transport. Crosslinking strategies span photochemical activation, thermal curing and click-chemistry approaches, each tailored to preserve or even boost carrier mobility and light absorption. The ensuing films exhibit improved mechanical resilience, diminished morphological drift under prolonged operation and compatibility with scalable solution processing. Consequently, crosslinked polymer photovoltaics emerge as a promising route towards commercially viable organic solar cells, marrying high power conversion efficiencies with enhanced operational stability under real-world conditions.

Research from Nature Portfolio

Recent studies have pinpointed photoreactive azide derivatives as precision tools for network formation in conjugated polymers. In one approach, optimised fluorinated phenyl azides achieve near-unity quantum efficiency in nitrene insertion, selectively crosslinking unactivated C–H bonds within π-stacks. Structure–activity relationships reveal that ring substitution on the azide modulates binding affinity to polymer domains, thereby minimising carrier mobility quenching and enabling stable morphology in high-performance blends such as PBDB-T:ITIC and PM6:Y6. Another innovation employs a tetrahedral, four-arm photocrosslinker that integrates into diverse solution-processable semiconductors. Even at low loadings, the crosslinked network preserves intrinsic electrical characteristics while rendering films impervious to subsequent solvent exposures, facilitating high-resolution micropatterning and multilayer stacking. Additionally, a foundry-compatible photolithographic technique utilises a UV-curable additive in a vertically phase-separated polymer blend, enabling ambient‐processable patterning at sub-micrometre resolution. The resulting thin-film transistors demonstrate excellent charge transport, thermal resilience up to 175 °C and mechanical flexibility, illustrating crosslinking’s role in advancing integrated polymer electronic devices.

Crosslinked Polymer Photovoltaic Systems publication trend

The graph below shows the total number of articles in crosslinked polymer photovoltaic systems across all publications each year (not limited to Nature Index journals).

Technical terms

Crosslinking: The formation of covalent bonds between polymer chains to create a three-dimensional network that enhances mechanical and thermal stability.

Nitrene: A reactive nitrogen species generated by photolysis or thermolysis of organic azides, capable of inserting into C–H bonds and initiating crosslinking.

Photocrosslinker: A molecule bearing light-activated functional groups (e.g., azides or diazirines) that, upon irradiation, generate reactive intermediates for network formation.

Bulk heterojunction: A nanoscale blend of electron-donor and electron-acceptor materials in an interpenetrating morphology, optimised for charge separation and transport in organic solar cells.

π-Conjugated polymer: A polymer with alternating single and double bonds along its backbone, enabling delocalised electrons for semiconducting and photoactive properties.

References

1. Optimization of fluorinated phenyl azides as universal photocrosslinkers for semiconducting polymers. Nature Communications (2024).
2. Universal three-dimensional crosslinker for all-photopatterned electronics. Nature Communications (2020).
3. Foundry-compatible high-resolution patterning of vertically phase-separated semiconducting films for ultraflexible organic electronics. Nature Communications (2021).
4. Dual Function Additives: A Small Molecule Crosslinker for Enhanced Efficiency and Stability in Organic Solar Cells. Advanced Energy Materials (2015).
5. Bis-Azide Low-Band Gap Cross-Linkable Molecule N3‑[CPDT(FBTTh2)2] to Fully Thermally Stabilize Organic Solar Cells Based on P3HT:PC61BM. ACS Omega (2017).
6. Reactive & Efficient: Organic Azides as Cross-Linkers in Material Sciences. Molecules (2020).