16.55% Power Conversion Efficiency Achieved in PM6:Y6 Organic Solar Cells Based on Salicylic Acid-Doped ZnO

Abstract

In this work, we successfully developed a high-performance hybrid cathode interlayer by doping low-cost salicylic acid (SA) into zinc oxide (ZnO), denoted as ZnO:SA. This modification strategy effectively reduces the surface work function (WF) 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 and after 600 minutes of exposure to 100 mW/cm² 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 doping is a simple, lowcost, and effective approach to modify 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.