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 lambda(max) of 667nm and a strong luminescence maximum wavelength at 765nm. The photovoltaic performance based on a newly developed squaraine dye shows a short-circuit photocurrent density (J(SC)) of 8.6mA/cm(2), an open-circuit voltage (V-OC) of 435V, and a fill factor (FF) of 0.68 corresponding to an overall conversion efficiency (eta) of 2.6%.