Efficient and moisture-resistant organic solar cells simultaneously reducing the surface defects and hydrophilicity of an electron transport layer

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 9; no. 38; pp. 135 - 1358
• Main Authors: Gao, Xueman, Su, Zhenhuang, Qu, Shengchun, Zhang, Wenzhi, Gao, Yueyue, He, Shenghua, Wang, Zhijie, Shang, Luwen, Dong, Guohua, Yue, Gentian, Tan, Furui, Wang, Zhangguo
• Format: Journal Article
• Published: 07.10.2021
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d1tc03409j

Organic solar cells (OSCs) simultaneously featuring good photovoltaic performance and strong humidity resistance are greatly anticipated for their practical application. Herein, we developed a simple organic trisiloxane molecule (denoted as TSi), and applied it to modify sol-gel ZnO (sg-ZnO) films. Compared to pristine sg-ZnO films, the TSi/sg-ZnO film presents fewer surface defects, shallower work function, and stronger hydrophobicity. Benefiting from those improved characteristics, when adopting a benzodifuran (BDF)-based polymer (BDFP-Bz) and Y6 as the electron donor and acceptor to fabricate OSCs, the derived devices utilizing TSi/sg-ZnO as the electron transport layer (ETL) showed suppressed charge recombination, enhanced charge extraction and increased stability to moisture versus the devices based on an sg-ZnO ETL. Meanwhile, PBDFP-Bz:Y6 OSCs based on a TSi/sg-ZnO ETL delivered a higher PCE of 14.62% than that of the control devices (12.39%). More importantly, the TSi/sg-ZnO ETL was also applicable in other different photovoltaic systems, among which PM6:Y6 OSCs based on a TSi/sg-ZnO ETL yielded a superior PCE of 16.37% along with stronger stability to moisture versus the reference ones. Our finding demonstrates the TSi/sg-ZnO bilayer ETL holds promise in the practical application of OSCs for simultaneously improving the photovoltaic performance and moisture-resistance of devices. A novel low-cost TSi/ZnO bilayer electron transport layer was developed, which could simultaneously enhance the efficiency and device stability to moisture of derived OSCs.