Ag Nanoparticle Layer on PEDOT:PSS with Optimized Energy Levels for Improving PM6:Y6-Based Organic Photovoltaics

Recent advances in donor and acceptor molecules have significantly enhanced the efficiency and competitiveness of organic solar cells. However, optimizing the interfaces remains a critical issue in increasing the photovoltaic performance, mainly to reduce charge accumulation between the hole transport layers (HTLs) and the active layer. In this work, the interface between PM6:Y6 (active layer) and PEDOT:PSS (HTL) has been modified with silver nanoparticles (AgNPs). These AgNPs have been synthesized in anhydrous chlorobenzene by laser ablation synthesis in solution (LASiS). The choice of chlorobenzene as the medium for the synthesis of NPs by LASiS allows direct deposition onto the HTL. Measurements performed using steady-state current-voltage (J-V), Photo-CELIV, and current/voltage transient (TPC/TPV) revealed enhanced and reproducible photovoltaic parameters. The AgNPs also improve the device stability and can also be used on top of other HTLs, such as Br-2PACz. Theoretical analyses were performed by fitting an analytical model to the experimental data of photocurrent, which showed that the AgNP layer reduced bimolecular recombination losses. These findings suggest that the AgNP-modified interface of the PEDOT:PSS/active layer is a promising and versatile strategy to optimize interfacial properties, thus minimizing recombination losses and enhancing the efficiency, reproducibility, and stability of organic solar cells.