Abstract
We synthesized a novel wide bandgap polymer, PDTFBT, forming a weak donor (WD)-weak acceptor (WA) structure for use in organic photodetectors (OPDs) and organic solar cells (OSCs). The fluorination in the D unit and the alkoxy substitution in the A unit induced WD and WA properties, respectively. The WD-WA structure of PDTFBT effectively broadened the bandgap compared to typical D-A structures, and the S-F and S-O dipole-dipole interactions induces a highly planar backbone structure with excellent π-π stacking in the vertical direction. In OPDs, conformationally less disordered PDTFBT polymer retained the constant responsivity and significantly improved the detectivity of PDTFBT:PC71BM devices even with a thick active layer of 470 nm, contrary to the variation in the responsivity of P3HT:PC61BM devices depending on the thickness. In OSCs, the deep HOMO energy level (−5.57 eV) of PDTFBT led to high Voc of 0.92 V in PDTFBT:PC71BM devices, which was 0.3 eV higher than that of P3HT:PC61BM devices (0.62 V), resulting in 1.8-fold enhanced power conversion efficiency. We demonstrated that the WD-WA structure with S-F and S-O interactions is highly promising strategy to make wide bandgap polymers for organic photodetectors and for the bottom cell of tandem architecture.
Original language | English |
---|---|
Pages (from-to) | 173-182 |
Number of pages | 10 |
Journal | Organic Electronics: physics, materials, applications |
Volume | 46 |
DOIs | |
Publication status | Published - 2017 Jul 1 |
Keywords
- Alkoxy benzothiadiazole
- Fluorination
- Organic photodetectors
- Organic solar cells
- Wide bandgap polymer
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Chemistry(all)
- Condensed Matter Physics
- Materials Chemistry
- Electrical and Electronic Engineering