A Near-IR Organic Sensitizer with Squaraine and Phenothiazine Unit for Dye-Sensitized Solar Cells

Abstract

A new unsymmetrical squaraine-based near-IR sensitizer (SGT-202), where electron-rich bithiophene conjugated fragment was used to link to the squaraine core and phenothiazine unit as electron-donating group, was synthesized and applied for dye-sensitized solar cells. The SGT-202 dye exhibits the λ_max of 667 nm and a strong luminescence maximum wavelength at 765 nm. The photovoltaic performance based on a newly developed squaraine dye shows a short-circuit photocurrent density (J_SC) of 8.6 mA/cm², an open-circuit voltage (V_OC) of 435V, and a fill factor (FF) of 0.68 corresponding to an overall conversion efficiency (η) of 2.6%.

Keywords:

• panchromatic dye
• squaraine
• phenothiazine
• near-IR dye
• dye-sensitized solar cells