Improved optoelectrical properties for organic solar cells by introducing silicon quantum dots via eco-friendly and simple process

Abstract

In this study, we synthesized eco-friendly silicon quantum dots (SiQDs) with absorption ≤400 nm and light emission of 440 nm and 500–550 nm. SiQDs were introduced into ZnO (sol-gel), an electron transport layer (ETL) of organic solar cells (OSCs) with an inverted structure.The introduction of SiQDs led to a smoother and more uniform surface morphology of the ETL. SiQDs improved the carrier mobility of the device, and increased carrier transport by reducing carrier recombination and interfacial resistance. Furthermore, SiQDs were found to convert ultraviolet (UV) light to visible light via light conversion effect. They contributed to improved JSC and FF in OSCs, and improved the power conversion efficiency (PCE) from 14.48 % to 15.31 % for the PM6:BTP-eC9 device (JSC: 24.42 mA cm−2 to 24.87 mA cm−2, FF: 73.05 %–75.23 %) and from 15.43 % to 16.3 % for the PM6:L8-BO device (JSC: 23.37 mA cm−2 to 24.57 mA cm−2, FF: 75.95 %–76.77 %).SiQD-doped ZnO, with eco-friendly synthesized SiQDs, not only improved the efficiency with the ETL of OSCs, but also demonstrated good stability.