Mesoporous ZnO/TiO2 photoanodes for quantum dot sensitized solar cell

Abstract

In the present work, different photoanodes, namely ZnO/TiO2 and bare TiO2 were deposited on fluorine-doped tin oxide (FTO) conductive glass substrate by the doctor blade method. CdS quantum dot was deposited on the photoanode by using the successive ionic layer adsorption and reaction (SILAR) method. In this, CuS was also coated on the FTO substrate which acts as the counter electrode. The structural, optical and electrical properties of deposited photoanodes and counter electrode were successfully investigated. The J-V characteristic and the other parameters of quantum dot sensitized solar cell (QDSSC) were analyzed by a using solar simulator under the illumination of a xenon short arc lamp an AM 1.5 G spectrum, having the light intensity of 100 mWcm−2. The power conversion efficiency of QDSSC using different photoanodes were compared. Due to the formation of energy barrier, ZnO/TiO2 using CdS QDs have higher efficiency (̴ 1.73%) as compared to bare TiO2 using CdS QDs (̴ 1.01%). It was found that ZnO/TiO2 based QDSSC exhibits 71% higher efficiency than that of TiO2 based QDSSC. The incident photon-to-current conversion efficiency (IPCE) obtained for ZnO/TiO2 electrode were approximately 46% (at 465 nm) and for bare TiO2 electrode around 34% (at 446 nm). The overall investigation supports the electron transport and enhanced performance of the ZnO/TiO2/CdS solar cell.