Plasmonic Effect in Au-Added TiO2-Based Solar Cell

Abstract

TiO2 nano thin films have been fabricated on fluoride tin oxide (FTO) film electrodes by hydrothermal synthesis at temperatures of 80°C, 120°C, 150°C, and 200°C for different synthesis times of 1 h, 2 h, and 3 h in 2.5 mol, 5 mol, and 7.5 mol NaOH solution. X-ray diffraction patterns and field-emission scanning electron microscopy (FESEM) images were recorded for all the film samples, and the results confirmed that TiO2 anatase phase was generally formed in nanowire form. The influence of synthesis temperature, processing time, and NaOH content on the structure and morphology of the TiO2 material was studied. Au nanoparticles with size of around 2 × 10−8 m were added into the TiO2 thin films by thermal evaporation in vacuum combined with thermal annealing. Based on photocurrent–voltage (I–V) characteristics measured under irradiation with visible light, the short-circuit current, open-circuit voltage, and efficiency of solar cells with FTO/Au-added TiO2/(I−/I2−) electrolyte/Pt configuration were evaluated. The short-circuit current and efficiency of the Au-added solar cell were greatly improved, which is supposed to be related to a contribution of the surface plasmon resonance effect.