16.55% power conversion efficiency achieved in PM6:Y6 organic solar cells based on salicylic acid-modified ZnO

Abstract

In this work, we successfully developed a high-performance hybrid cathode interlayer by modifying zinc oxide (ZnO) with low-cost salicylic acid (SA), denoted as ZnO:SA. This modification strategy effectively reduces the surface work function (W_F) of ZnO, optimizes thin-film morphology, passivates surface defects, and suppresses the recombination of photogenerated carriers. When ZnO:SA was employed as the electron transport layer (ETL) in inverted organic solar cells (i-OSCs) based on PM6:Y6, the device achieved a power conversion efficiency (PCE) of 16.55%. In contrast, the reference device with pure ZnO as the ETL only exhibited a PCE of 14.86%. Furthermore, the ZnO:SA-based device showed enhanced stability under continuous illumination; after 600 minutes of exposure under 100 mW cm⁻² light intensity, it retained ∼88.2% of its initial PCE, while the pure ZnO-based device maintained only ∼61.3%. These results demonstrate that SA surface modification is a simple, low-cost, and effective approach to tailor ZnO for high-performance ETLs. The significantly improved efficiency and stability of ZnO:SA-based i-OSCs provide robust support for their potential application in advanced organic photovoltaic technologies.