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

Abstract

Abstract 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 ( V oc ) 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 ( J sc ) 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.