5,6‐Bis(octyloxy)benzo[c][1,2,5]thiadiazole‐Bridged Dyes for Dye‐Sensitized Solar Cells with High Open‐Circuit Voltage Performance

Three new metal‐free dyes with a 5,6‐bis(octyloxy)benzo[c][1,2,5]thiadiazole core (DOBT‐I–III) have been designed and synthesized for use as DSSCs. Their absorption properties and electrochemical and photovoltaic performances have been investigated systematically. The DSSCs based on DOBT‐I–III show high open‐circuit voltages (Voc) of 829, 818, and 784 mV, respectively. Of the three dyes, DOBT‐III, which contains a thiophene‐bridging linker, exhibits the best photovoltaic performance: a short‐circuit photocurrent density (Jsc) of 12.74 mA cm–2 and a fill factor (FF) of 0.73, which corresponds to an overall conversion efficiency of 7.29 % under standard global AM 1.5 solar conditions.