Synthesis via a direct adsorption method and characterization of Cu 2+ -doped CdTe quantum-dot-sensitized TiO 2 nanotubes for use as a photoanode

A direct adsorption method for the synthesis of Cu2+-doped CdTe quantum dot (QD)-sensitized TiO2 nanotubes (TNTAs) for use as a photoanode is reported in this study. The influences of the molar concentration of Cu2+, the sensitization temperature, the sensitization time, and the loop index on the photovoltaic performance of the CdTe:Cu2+/TNTAswas investigated. Scanning electron microscopy images showed that the CdTe:Cu2+ QDs are well dispersed on the TNTA surface. UV–vis adsorption measurements showed that the visible absorption of the TNTAs was enhanced by the CdTe:Cu2+ QD sensitization. Whereas the power conversion efficiency (PCE) of the bare TNTAs was 0.11%, the maximum PCE of the CdTe:5%Cu2+/TNTAs was 3.70% with a sensitization time of 5.0 h, a sensitization temperature of 60 °C, and a loop index of 2. Therefore, CdTe:5%Cu2+/TNTAs may be employed in quantum-dot-sensitized solar cells.