An asymmetric small-molecule donor enables over 18% efficiency in ternary organic solar cells. Issue 17 (4th April 2022)

• Record Type: Journal Article
• Authors: Guan, Ming; Tao, Wuxi; Xu, Linyong; Qin, Youmei; Zhang, Jianqi; Tan, Songting; Huang, Meihua; Zhao, Bin
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 17(2022)
• Page Start: 9746
• Page End: 9752
• Publication Date: 2022-04-04
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta00564f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : An asymmetric small-molecule donor TTBT-R, incorporated with benzo[2, 1-b:3, 4- b ′]dithiophene derivative as the core, was exploited for ternary OSCs, and the ternary OSCs base on PM6:Y6 as the host and TTBT-R as the guest achieved a PCE of 18.07%. Abstract : An asymmetric small molecule donor, TTBT-R, incorporated with 4, 5-di(2-ethylhexyl)oxybenzo[2, 1- b :3, 4- b ′]dithiophene as the core, was exploited for high-performance ternary organic solar cells (OSCs), and possesses a complementary absorption band and cascaded energy levels with PM6 and Y6. The ternary blend film (PM6:TTBT-R:Y6 = 0.9 : 0.1 : 1) attains the most optimized morphology with a nanofiber-like structure and small domain size as well as strong face-on molecular packing, which leads to the most balanced charge transport, highest charge mobilities and lowest charge recombination in its device. In addition, TTBT-R possesses a lower-lying HOMO energy level than PM6, which brings about higher V oc in ternary OSCs. Accordingly, the ternary OSC with 10 wt% TTBT-R achieved a PCE of 18.07% due to the comprehensively improved V oc (0.863 V), J sc (27.38 mA cm −2 ), and FF (76.46%) values compared with the PM6:Y6 binary OSC. This work provides not only a small molecule with 4, 5-dialkyloxybenzo[2, 1- b :3, 4- b ′]dithiophene as the core but also an asymmetric strategy with a non-fused structure to tune the molecular packing, energy levels and absorption spectrum of small molecules for constructing high-performance ternary OSCs.