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 J _SC 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.