VIS harvesting unsymmetrical squaraine dye for dye-sensitized solar cells

Abstract

An unsymmetrical squaraine dye which contains an arylamino group was synthesized and used in dye-sensitized solar cells. The molar extinction coefficient of the dye is 77793 M −1 cm −1. Because our synthesized molecule may have no diradical character or the contribution of the diradicaloid component to resonance is quite small, the newly designed squaraine dye has a maximum absorption at 546 nm in the visible region compared with the NIR squaraine sensitizers. Cyclic voltammetry and time dependent density function theory calculation were accomplished to scrutinize the sensitized performance of the dye. Meanwhile, the novel sensitizer has been used to sensitize nanocrystalline TiO 2-based solar cell. Under standard global AM 1.5 solar conditions, the squaraine dye-sensitized cell gives a short circuit photocurrent density ( J SC) of 5.84 mA/cm 2, an open circuit voltage of ( V OC) 0.658 V, and a fill factor (ff) of 0.448, corresponding to an overall conversion efficiency ( η) of 1.72%.