Enhancing the efficiency and stability of inverted binary organic solar cells through hydroxylated perylene diimide derivative cathode interlayers

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 11; pp. 6644 - 6651
• Main Authors: Tian, Li, Feng, Lingwei, Guo, Shukui, Wang, Renjie, Zhang, Kai, Cui, Cheng-Xing
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 12.03.2024
• Subjects: Cathodes; Charge transport; Commercialization; Diimide; Efficiency; Energy conversion efficiency; Energy gap; Interlayers; Molecular orbitals; Photovoltaic cells; Solar cells; Stability
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta07443a

Cathode interlayers (CILs) are crucial components in organic solar cells (OSCs), and the quest for outstanding overall performance in these materials remains a central research focus. In this study, we introduced a series of cost-effective perylene diimide derivatives (PDI derivatives) featuring hydroxylated side chains, namely PDI-Br-0O , PDI-Br-1O , and PDI-Br-3O . These hydroxylated CILs exhibit wider optical bandgaps and possess low-lying molecular orbitals, which can contribute to efficient photon utilization and enhanced charge transport within OSCs. As a result, the inverted cell with PDI-Br-3O achieved an outstanding power conversion efficiency (PCE) of 18.1%, representing one of the highest values recorded in inverted binary OSCs. Furthermore, these hydroxylated PDI derivatives enabled OSCs to consistently achieve PCEs exceeding 17%, even with a 30 nm-thick PDI-Br-3O layer. Of particular significance, the operational stability of these solar cells was notably improved with increasing the CIL thickness in the range from 5 nm to 30 nm. Remarkably, even after continuous illumination for 550 hours, the device equipped with a 30 nm-thick PDI-Br-3O CIL still retained 83% of its original efficiency. This study presents a promising design strategy for CILs offering exceptional comprehensive performance, providing a significant impetus for the potential commercialization of OSCs. We report a series of hydroxylated PDI derivatives as CILs with exceptional comprehensive performance. After continuous illumination, the extrapolated T 80 lifetime for the device with a 30 nm-thick PDI-Br-3O is estimated to be 3995 h.