Performance improvement of dye-sensitized solar cells by using TiO2 compact layer and silver nanowire scattering layer

Abstract

In this study, indium tin oxide (ITO) glass was coated with silver nanowires (AgNWs) by ultrasonic spray coating to roughen the ITO surface, yielding a surface texture comparable to that obtained by chemical etching. A compact layer (CL) of titanium dioxide (TiO2) was coated on the AgNWs/ITO surface by sputtering to improve the properties of dye-sensitized solar cell (DSSC). A TiO2 CL was used as a protective layer on AgNWs to prevent oxidation and increase the adhesion of AgNWs. The TiO2 CL also effectively inhibited the carrier recombination between the electrolyte solution and ITO interface, thereby improving the photoelectric conversion efficiency (η) of the DSSC device. The experiment results indicated that the η of DSSC devices with a CL deposited under the working electrode increased from 4.06% to 4.37%. The integration of the CL and AgNWs to CL/AgNWs/ITO structure increased the η of DSSC devices further to 4.59%. Electrochemical impedance spectroscopy was performed to analyze two DSSC structures, namely CL/ITO and CL/AgNWs/ITO; the electron lifetime increased from 0.35 ms to 0.55 ms and the charge collection rate increased from 64.5% to 75.2%. Therefore, CL/AgNWs/ITO working electrode structure can effectively improve the performance of DSSC devices.