Influence of Cu2+ dopant in optical property of CdTe quantum dots and photoelectrochemical performance of CdTe:Cu2+/TiO2 nanotube arrays

• CdTe:Cu2+ quantum dots are synthesized using a one-step method in aqueous solution.
• The high quantum yields of the as-prepared quantum dots was calculated 52.1%.
• The tunable band gaps of obtained CdTe:5% Cu2+ QDs ranging from 2.28 to 2.13 eV.
• The photoelectric conversion efficiency of CdTe:5% Cu2+ (3.0 h)/TNTAs is 1.24%.

A novel one-step synthesis process was used to prepare CdTe:Cu2+/TiO2 nanotube arrays (TNTAs). X-ray powder diffraction and high-resolution transmission electron microscopy analyses confirmed that the obtained CdTe:Cu2+ quantum dots (QDs) possess cubic structures, which are approximately spherical, and a small particle size (2.95 nm). The photoluminescent and UV–visible absorption spectra of CdTe:Cu2+ QDs also display an obvious redshift, which was attributed to the replacement of Cd2+ with Cu2+. Compared with that of the TNTAs and CdTe/TNTAs, the photoelectric conversion efficiency of CdTe:5% Cu2+/TNTAs increased by 785.7% and 103.3%, respectively. The incident photo-to-current conversion efficiency of CdTe:5% Cu2+/TNTAs was 50.6%, which indicated the potential use of QDs in photochemical solar cells.

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