Induced J-aggregation in acceptor alloy enhances photocurrent

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2019,（15）
• 页码范围: 1083-1086
• 页数: 4页
• 语种: 英文

摘要

Carbon-oxygen-bridged (CO-bridged) ladder-type units already proved to be promising electron-donating building blocks for making acceptor-donor-acceptor (A-D-A) nonfullerene acceptors [1].Compared with traditional carbon-bridged (C-bridged) units,CObridged units present stronger electron-donating capability due to electron-rich oxygen atoms.Their A-D-A acceptors show lower bandgaps and stronger light-harvesting capability due to enhanced intramolecular charge transfer (ICT).Ding et al.have designed pentacyclic [2],hexacyclic [3],heptacyclic [4] and octacyclic [5,6] CObridged units,and corresponding A-D-A acceptors.Among CObridged units,the octacyclic unit COi8 shows the strongest electron-donating capability and the largest molecular plane,rendering A-D-A acceptor COi8DFIC a very low bandgap of 1.26 eV and good electron mobility.COi8DFIC shows excellent near infrared (NIR) light-harvesting capability and outstanding performance in organic solar cells.Single-junction and tandem solar cells based on COi8DFIC gave record power conversion efficiencies (PCEs) of 14.62％ and 17.36％,respectively [7,8].In this work,a decacyclic CO-bridged unit COi10 and its A-D-A acceptor COil0DFIC were developed (Fig.1a).COi10DFIC possesses a larger molecular plane and a lower bandgap than COi8DFIC.PTB7-Th:COi10DFIC solar cells afforded a PCE of 10.90％.COi10DFIC can induce remarkable J-aggregation of COi8DFIC.Ternary solar cells based on PTB7-Th,COi10DFIC and COi8DFIC gave high photocurrent and a decent PCE of 13.48％.