VIS harvesting unsymmetrical squaraine dye for dye-sensitized solar cells

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 TiO2-based solar cell. Under standard global AM 1.5 solar conditions, the squaraine dye-sensitized cell gives a short circuit photocurrent density (JSC) of 5.84 mA/cm2, an open circuit voltage of (VOC) 0.658 V, and a fill factor (ff) of 0.448, corresponding to an overall conversion efficiency (η) of 1.72%.

► An unsymmetrical squaraine dye was synthesized and used in DSSCs.
► The unsymmetrical squaraine dye showed high extinction coefficient in the visible region.
► The device efficiency of the DSSCs made by this squaraine dye was 1.72%.
► The efficiency of the device may be influenced by the structure of the dye.