A Cost-Effective Alpha-Fluorinated Bithienyl Benzodithiophene Unit for High-Performance Polymer Donor Material

Abstract

To 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.

Cost-effective polymer donors with simple structure for organic solar cells

“…But the synthesis of BDTT-F units is very tedious and costly. Li et al 107 designed and synthesized an alpha-fluorinated bithienyl benzodithiophene (α-BDTT-F, with the F atom in the α position of thiophene) with fewer synthetic steps, higher synthetic yield, shorter purification time and lower cost. They 107 developed two polymers PBQ10 and α-PBQ10 (Fig.…”

“…Li et al 107 designed and synthesized an alpha-fluorinated bithienyl benzodithiophene (α-BDTT-F, with the F atom in the α position of thiophene) with fewer synthetic steps, higher synthetic yield, shorter purification time and lower cost. They 107 developed two polymers PBQ10 and α-PBQ10 (Fig. 7) with BDTT-F and α-BDTT-F as the donor unit, respectively, and Qx as the acceptor unit.…”

Preparation of Novel Organic Polymer Semiconductor and Its Properties in Transistors through Collaborative Theoretical and Experimental Approaches

“…At the same time, due to the preparation efficiency and flexibility of polymer materials, more and more research has been conducted on organic polymer systems [4]. After two decades of development, a variety of material systems have been developed and applied to a wide range of devices, including organic field-effect transistors, organic light-emitting devices, organic solar cells, sensors, memory storage, and organic thermoelectric and other functional devices [5][6][7][8][9][10]. In the case of organic transistors, for example, the primary performance indicators are electron and/or hole carrier transport and sensitive switching ratios [11,12].…”