Effect of TiO2 compact layer and ITO texturing on DSSC efficiency improvement by chemical deposition and etching process

Abstract

In this study, an indium tin oxide (ITO) glass surface was roughened, and liquid phase deposition (LPD) was used to create TiO₂ compact layers to improve the efficiency of dye-sensitized solar cells (DSSCs). ITO glass substrates were first etched with HCl to increase the surface roughness and effectively scatter incident light into the working electrode of a DSSC. This increased the traveling path of the light and light-capturing ability of the cell, thereby enhancing the light absorbance rate. Then, LPD was conducted to create a TiO₂ compact layer. The deposition reaction of a chemical liquid was induced to evenly cover the roughed ITO glass surface by using the compact layer. The LPD-TiO₂ compact layer effectively inhibited charge recombination on the electrolyte/ITO interface, which enhanced the photovoltaic conversion efficiency of the DSSC. The results verified that the photovoltaic conversion efficiency of the DSSC with the roughened ITO glass improved from 4.67 to 5.05%. After the LPD-TiO₂ compact layer was installed, the photovoltaic conversion efficiency was further enhanced to 5.91%, thereby achieving a 26.55% increase in efficiency. An electrochemical impedance spectroscopy revealed that the carrier lifetime increased from 7.17 to 9.34 ms, and the charge collection rate improved from 69.44 to 70.92%. This indicated that the roughened ITO glass and LPD-TiO₂ compact layers were highly compatible. Using LPD to cover the uneven ITO glass surface by using an LPD-TiO₂ is key to improving the light absorbance rate of DSSC and inhibiting carrier recombination.