A
tailor-made medium-band gap fluorinated quinoxaline-based conjugated polymer of
PBDT-TFQ was designed and synthesized as a donor material for bulk-heterojunction (BHJ) solar cells. This polymer is possessed of an intrachain donor鈥揳cceptor architecture and exhibits a broad and strong absorption spectrum across the entire UV鈥搗is region. The introduction of F atoms with high electron affinity to the quinoxaline moiety is effective in further lowering both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels of
PBDT-TFQ to at
tain higher open-circuit voltage (
Voc). With an optimized blend ratio of
PBDT-TFQ:PC
71BM (1:1, w/w), a high power conversion efficiency (PCE) of 8.0% was ob
tained, with a
Voc of 0.76 V, a short-circuit current density (
Jsc) of 18.2 mA cm
鈥?, and a fill factor (FF) of 58.1% under AM 1.5G irradiation. The resulting copolymer reveals an outstanding
Jsc value, arising from the higher hole mobility of
PBDT-TFQ, together with the better continuous percolation pathways within the polymer blend for efficient exciton dissociation and charge transport.
Keywords:
solar cells; taic&qsSearchArea=searchText">photovoltaic; quinoxaline; semiconductor; bulk heterojunction