cm6b02225_si_001.pdf (4.86 MB)

From Isoindigo to Dibenzonaphthyridinedione: A Building Block for Wide-Bandgap Conjugated Polymers with High Power Conversion Efficiency

Download (4.86 MB)
journal contribution
posted on 30.08.2016 by Mian Cai, Xichang Bao, Xiao Wang, Huanrui Zhang, Meng Qiu, Renqiang Yang, Chunming Yang, Xiaobo Wan
Most wide-bandgap (WBG) conjugated polymers with Eg > 2.2 eV exhibit low power conversion efficiency (PCE) due to their limited absorption window. Here we report the synthesis of a novel tetracyclic fused building block dibenzonaphthyridinedione (DBND) from isoindigo and its application as an acceptor building block for wide-bandgap copolymers with improved PCE. The Stille copolymerization of this building block with 5,5′-bis­(trimethylstannyl)-2,2′-bithiophene (2T) and (E)-1,2-bis­(5-(trimethylstannyl)­thiophen-2-yl)­ethane (TVT) results in two WBG polymers PDBND-2T (Eg 2.32 eV) and PDBND-TVT (Eg 2.23 eV), respectively. Both polymers act as excellent donors in high-performance organic solar cells (OSCs). When blended with phenyl-C71-butyric acid methyl ester (PC71BM), PDBND-2T based OSCs exhibit a PCE of 5.75%, which makes it the broadest bandgap OSCs with PCE over 5%. PDBDN-TVT based OSCs featured a high PCE up to 6.32%. Such efficiency is the highest reported to date for a conjugated polymer at such a broad bandgap. Moreover, without additives or annealing process, PDBND-TVT based OSCs exhibit an efficiency around 6.0% with a thick active layer (240 nm) and the performance shows little sensitivity to polymer:PC71BM weight ratios (range from 1:1.5 to 1:3), which makes PDBND-TVT a potential material for processable large-area tandem or ternary OSCs.

History

Exports