Metal-Free Indeno[2,1-b]thiophene-Based Sensitizers for Dye-Sensitized Solar Cells

A series of indeno[2,1-b]thiophene-containing organic dyes (IDT1–IDT5) have been synthesized, and their UV/Vis spectra extend beyond 700 nm. These dyes were employed as sensitizers for dye-sensitized solar cells (DSSCs). Among them, dyes IDT3–IDT5 with a thiophene unit conjugated with an anchor have better light harvesting ability and higher JSC values. Dye aggregation contributes substantially to the photocurrent in the near infrared region. The dye IDT5, with chenodeoxycholic acid (CDCA) as the co-adsorbent, has the highest power conversion efficiency (5.06 %) under AM 1.5G simulated sunlight irradiation, which is 68 % of the standard device based on N719 dye.