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A Cost-Effective Alpha-Fluorinated Bithienyl Benzodithiophene Unit for High-Performance Polymer Donor Material
journal contribution
posted on 2021-11-10, 14:33 authored by Wenqing Zhang, Chenkai Sun, Shucheng Qin, Ziya Shang, Shaman Li, Can Zhu, Guang Yang, Lei Meng, Yongfang LiTo
reduce synthetic cost of the classic fluorinated bithienyl benzodithiophene
(BDTT-F) unit, here, an alpha-fluorinated bithienyl benzodithiophene
unit, namely, α-BDTT-F (F atom in the α position of the
lateral thiophene unit), is developed by the isomerization strategy
of exchanging the positions of the F atom and flexible alkyl chain
on the lateral thiophene unit of the BDTT-F unit. The α-BDTT-F
unit was synthesized with less synthetic steps, higher synthetic yield,
and less purification times from the same raw materials as those of
the BDTT-F unit, thus with low synthetic cost. Theoretical calculation
indicates that the α-BDTT-F unit possesses a similar twisted
conformation and electronic structures as those of the BDTT-F unit.
The α-BDTT-F-based polymer α-PBQ10 exhibits similar light
absorption and energy levels as those of the corresponding BDTT-F-based
polymer PBQ10 but marginally increased molecular aggregation and stronger
hole transport than PBQ10. In consequence, the α-PBQ10:Y6-based
polymer solar cell demonstrates a slightly enhanced power conversion
efficiency (PCE) of 16.26% compared with that of the PBQ10:Y6-based
device (PCE = 16.23%). Also, the PCE is further improved to 16.77%
through subtle microscopic morphology regulation of the photoactive
layer with the fullerene derivative indene-C60 bisadduct as the third
component. This work provides new ideas for the design of low-cost
and high-efficiency photovoltaic molecules.
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theoretical calculation indicatesstronger hole transportsimilar twisted conformationless synthetic stepsless purification timeshigher synthetic yieldfullerene derivative indeneflexible alkyl chainefficiency photovoltaic moleculesreduce synthetic costlateral thiophene unitbased polymer αbased polymer pbq10low synthetic costf unit possessesbased devicef unitα positionthird componentraw materialsphotoactive layerisomerization strategyf atomenergy levelselectronic structuresc60 bisadduct23 %).