Plasmonic vortex-coupled forward emission (PVCFE): a novel light coupling mechanism in aluminium nanostructures for high-efficiency, stable, and cost-effective organic photovoltaics

Abstract

The dual challenge of enhancing power conversion efficiency (PCE) while ensuring long-term stability is paramount for the commercial viability of organic photovoltaics (OSCs). This work confronts these challenges by identifying a novel, material-dependent light coupling mechanism—termed plasmonic vortex-coupled forward emission (PVCFE)—and embedding it within a holistically designed, stable, and cost-effective device architecture. Through a rigorous multiphysics simulation workflow that accurately isolates useful optical generation from parasitic losses, we discover that non-noble metal nanostructures like aluminium (Al) support complex, hybridized plasmon modes. Phase-resolved electromagnetic field analysis reveals that PVCFE involves the synchronous coupling of a vortical near-field with a directional energy channeling component, which actively “pumps” optical energy deep within the organic active layer. Harnessing this discovery, we computationally designed and optimized an inverted OSC based on a high-performance PTB7:PC₇₁BM active layer with a robust AZO ETL and a chemically inert graphite anode. The final, optimized Al-core/Al₂O₃-shell enhanced device is predicted to exhibit a remarkable 57% relative increase in PCE, reaching a simulated 9.34% compared to the 5.95% intrinsic baseline. This breakthrough is driven by a massive 55.8% increase in short-circuit current to 18.09 mA cm⁻², stemming from the PVCFE mechanism and estimated hot carrier contributions, while impressively maintaining the fill factor. Our findings suggest that Al is a potentially superior plasmonic material for high-performance OSCs and introduce PVCFE as a new design paradigm for engineering light–matter interactions in nanophotonic devices.