Photovoltaic performances of Cu2-xTe sensitizer based on undoped and indium3+-doped TiO2 photoelectrodes and assembled counter electrodes

Novel binary Cu2-xTe nanoparticles based on undoped and indium-doped TiO2 photoelectrodes were synthesized using a successive ionic layer adsorption and reaction (SILAR) technique as a sensitizer for liquid-junction solar cells. A larger diameter of TiO2 promoted a narrower energy band gap after indium doping, attributing to yield a broader absorption range of nanoparticle sensitizer due to the increasing amount of Cu2-xTe NPs on TiO2 surface. The atomic percentages showed the stoichiometric formation of Cu2Te incorporated in a Cu2-xTe structure. The best photovoltaic performance with the lower SILAR cycle, i.e., n = 13 was performed after indium doping in both of carbon and Cu2S CEs and revealed that the efficiency of 0.73% under the radiant 100 mW/cm(2) (AM 1.5G). The electrochemical impedance spectroscopy (EIS) was used to investigate the electrical properties via effect of material doping and counter electrodes with a lower charge-transfer resistance (R-ct) and it was also found that the electron lifetime was improved after the sample doped with indium and assembled with carbon CE. (C) 2015 Elsevier Inc. All rights reserved.