Highly improved photocurrents of dye-sensitized solar cells containing ultrathin 3D inverse opal electrodes sensitized with a dithienothiophene-based organic dye

Abstract

Ultrathin but highly efficient dye-sensitized solar cells (DSCs) may be beneficial for making flexible devices and lowering production costs. Here, a uniform, ultrathin inverse opal (IO) electrode sensitized with a dithienothiophene (DTT)-based sensitizer (Carbz-PAHTDTT) was successfully prepared and demonstrated as a high-efficiency DSC electrode. The ultrathin IO was fabricated using a polystyrene opal template subsequently coated with TiO₂ via a chemical vapor deposition approach. The Carbz-PAHTDTT-sensitized IO film was compared to an IO film sensitized by a conventional N719 dye. The charge collection efficiency of the Carbz-PAHTDTT-sensitized TiO₂ IO electrode was comparable to the N719-sensitized electrode. However, the Carbz-PAHTDTT TiO₂ IO electrode DSCs exhibited remarkably high light-harvesting efficiency due to high adsorption density and visible light absorption features of the Carbz-PAHTDTT-sensitized electrode. The Carbz-PAHTDTT DSCs containing a 3.5 μm thick IO electrode displayed a photocurrent density of 11.23 mA cm⁻², which was 1.5 times higher compared to the N719-sensitized DSCs.