Fluorine substituted thiophene–quinoxalinecopolymer to reduce the HOMO level and increase the dielectric constant for high open-circuit voltage organic solar cells
- 11 December 2012
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry C
- Vol. 1 (4) , 630-637
Abstract
This study reported a novel fluorinated copolymer (FTQ) and shown it to exhibit a significantly higher open circuit voltage (VOC) in bulk heterojunction solar cells with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) compared to the low band-gap polymer Thiophene–Quinoxaline (TQ). Fluorination lowers the polymer HOMO level effectively which pushes down the highest occupied molecular orbital (HOMO) level of the TQ from −5.36 eV to −5.51 eV and increases the relative dielectric constant from 4.2 to 5.5, resulting in a high VOC. The highest VOC of 950 mV was achieved in the FTQ/PCBM solar cell device. For these optimized blends, the device made of FTQ:PC71BM with a 1 : 1 weight ratio yielded a high power conversion efficiency of 5.3% after a very short time thermal annealing process. These findings will be of importance for achieving high-performance of polymer solar cells by functional group substitution in low band gap polymers.Keywords
This publication has 37 references indexed in Scilit:
- Inverted polymer solar cells with 8.4% efficiency by conjugated polyelectrolyteEnergy & Environmental Science, 2012
- A new benzo[1,2-b:4,5-b′]difuran-based copolymer for efficient polymer solar cellsJournal of Materials Chemistry, 2012
- Random benzotrithiophene-based donor–acceptor copolymers for efficient organic photovoltaic devicesChemical Communications, 2012
- Roll-to-roll fabrication of polymer solar cellsMaterials Today, 2012
- Combination of Molecular, Morphological, and Interfacial Engineering to Achieve Highly Efficient and Stable Plastic Solar CellsAdvanced Materials, 2011
- High-efficiency inverted dithienogermole–thienopyrrolodione-based polymer solar cellsNature Photonics, 2011
- Simultaneous Enhancement of Open‐Circuit Voltage, Short‐Circuit Current Density, and Fill Factor in Polymer Solar CellsAdvanced Materials, 2011
- Bulk heterojunction solar cells with internal quantum efficiency approaching 100%Nature Photonics, 2009
- A complete process for production of flexible large area polymer solar cells entirely using screen printing—First public demonstrationSolar Energy Materials and Solar Cells, 2009
- Controlling the Morphology of Nanocrystal–Polymer Composites for Solar CellsAdvanced Functional Materials, 2003