Synthesis of organic dye containing an alkylenesulfanyl-bridged bithienyl π-linker and its use in dye-sensitized solar cells

•A novel organic dye bearing a unique and flexible alkylenesulfanyl-bridged bithienyl bridging framework between the donor and acceptor units was synthesized.•The new dye exhibited an enhanced photocurrent, because of redshifted optical absorption and reduced interfacial recombination.•The new dye displayed better photovoltaic performance than an analogue containing a rigid dithienothiophene bridge.

The synthesis and photovoltaic characteristics of a new organic dye, CU-L2, which has a unique and flexible alkylenesulfanyl-bridged bithienyl bridging framework between the phenylamino donor unit and cyanoacrylic acceptor unit, were demonstrated. CU-L2 exhibited better photovoltaic performance, with an enhanced photocurrent due to the redshifted optical absorption and reduced interfacial recombination, as compared to CU-L1, with its rigid dithienothiophene bridging motif between the same donor and acceptor units. The dye-sensitized solar cell fabricated with CU-L2 under optimized processing conditions presented a high power conversion efficiency of 6.63%.

Graphical abstractA new organic dye, CU-L2, bearing a unique and flexible alkylenesulfanyl-bridged bithienyl bridging framework between the donor and acceptor units was synthesized and evaluated in the photovoltaic characteristics for dye-sensitized solar cell (DSSC).Figure optionsDownload full-size imageDownload as PowerPoint slide