Indium tin oxide (ITO)–free, solution-processable transparent electrodes are increasingly recognized as crucial components for producing organic optoelectronic devices at low cost and on a large scale. Among the many alternatives to ITO, silver nanowires (AgNWs) have emerged as a highly promising option because they combine excellent optical transmittance with low sheet resistance, making them suitable for use in high-performance inverted organic photovoltaic (OPV) architectures. However, to realize their full potential particularly for roll-to-roll fabrication, AgNW networks typically require embedding within a multilayer electrode structure. Additionally, efficient carrier-selective interface layers that can be applied from solution are needed to ensure proper charge extraction and device stability. In this study, we introduce a simple yet highly effective strategy for improving AgNW-based transparent electrodes by incorporating a solution-processed pyridine interlayer. This pyridine layer acts as an electron-selective contact when deposited on top of ZnO and is positioned above both the AgNW network and the upper ZnO capping layer in ZnO/AgNW/ZnO (ZAZ) electrode structures. The incorporation of pyridine leads to a remarkable enhancement in the optoelectronic properties of the resulting ZAZ electrodes. Specifically, pyridine-modified ZAZ films achieve optical transmittances of 88.27% and 88.50% at 550 nm, paired with sheet resistances of 13.24 Ω/sq and 17.30 Ω/sq, respectively. These values correspond to figures of merit (FoM) of 21.69 and 17.00 Ω⁻¹, surpassing the performance of standard ITO electrodes. Beyond improving conductivity and transparency, the pyridine coating also effectively smooths the surface of the AgNW network, mitigating roughness-related issues that often hinder device performance.

Notably, this work represents the first demonstration of using pyridine functionalization to tune the surface potential and modify the work function of AgNW-based transparent electrodes. These interfacial modifications facilitate more efficient electron extraction while maintaining compatibility with fully solution-processed device fabrication. The pyridine-treated ZAZ electrodes also display strong stability, they retain their performance for up to three months under ambient environmental conditions and withstand thermal aging at 90 °C for up to three weeks without significant degradation. An additional advantage of the pyridine-coated ZAZ structure is its ability to function as a dual-purpose transparent electrode. Through a carefully engineered multi-step coating process, the electrode simultaneously supports efficient electron transport and effective electron collection, reducing interfacial losses and improving charge extraction in thick-film devices.

When integrated into fully solution-processed OPV devices, these dual-function electrodes enable a significant boost in photovoltaic performance. Devices constructed with pyridine-modified ZAZ electrodes reach a power conversion efficiency (PCE) of 9.95% and a fill factor (FF) of 63.34%, outperforming reference devices based on conventional ITO electrodes, which exhibit a PCE of 8.84% and an FF of 59.19% under comparable conditions (250 nm active-layer thickness and 0.150 cm² active area). Furthermore, the resulting organic solar cells demonstrate promising operational stability when tested under continuous illumination. Overall, this work highlights a practical and scalable approach to engineering high-performance, ITO-free transparent electrodes for organic solar cells. By utilizing a simple pyridine functionalization strategy, it provides valuable insights into interface engineering, work-function tuning, and device stability—paving the way for efficient, low-cost, and manufacturable organic optoelectronic technologies.