Si-Bridged Ladder-Type Small-Molecule Acceptors for High-Performance Organic Photovoltaics
Journal
ACS Applied Materials and Interfaces
Journal Volume
11
Journal Issue
1
Pages
1125-1134
Date Issued
2019
Author(s)
Abstract
In this study, we synthesized 5,11-dihexyl-4,4,10,10-tetraoctylbenzo[1,2-b:4,5-b′]bisthieno[4″,5″-b″:4″′,5″′-b″′]silolo[2″,3″-d:2″′,3″′-d′]thiophene (ArSi) as a ladder-type electron-rich core for the preparation of three acceptor-donor-acceptor-type nonfullerene acceptors (NFAs) - ArSiID, ArSiID-F, and ArSiID-Cl - featuring (3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (ID), 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (ID-F), and 2-(5,6-dichloro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (ID-Cl) as peripheral electron-poor units, respectively. These molecules exhibit strong absorption covering the region of 600-850 nm. The incorporation of the halogen atoms onto the terminal units adjusted the energy levels and light-harvesting ability of these materials. We employed the conjugated polymers J51 and PBDB-T, having middle optical energy gaps as donor together with these ArSi derivatives as acceptor to study the blend film morphology and the corresponding organic photovoltaic (OPV) performances. After optimization with device engineering works, a PBDB-T:ArSiID-F-based device with a power conversion efficiency up to 9.4% was achieved. This study is the first case to examine the effects of various halogen modifications on the performance of ArSi derivatives that serve as NFAs for OPVs. Our findings should encourage further investigations on this rarely studied core structure for optoelectronic applications. © 2018 American Chemical Society.
SDGs
Other Subjects
Conjugated polymers; Conversion efficiency; Ladders; Molecules; Nanostructured materials; conjugated; Fill factor; nonfullerene; Organic photovoltaics; Power conversion efficiencies; Silicon compounds
Type
journal article