Sensitization of TiO2 nanotube array photoelectrodes with MnxCdySe

Abstract

The photoanode obtained by the deposition of Mn_xCd_ySe nanocrystals onto TiO₂ nanotube arrays using a successive ionic layer adsorption and reaction technique realized a significant improvement in the charge transport and current generation compared with a pristine TiO₂ nanotube based anode. The concentration of manganese was determined to be 10% of the concentration of cadmium, and thus x = 0.1y. The widening of absorption spectra and the magnitude of photocurrent density were found to be significantly affected with a variation in the number of SILAR cycles and the annealing temperature. A stable photocurrent density of ∼8 mA cm⁻² under AM 1.5 illumination (1 sun) was achieved for Mn_xCd_ySe nanocrystals-embedded TiO₂ nanotube arrays heterostructure based photoelectrodes prepared through 9 cycles of SILAR deposition, followed by annealing at 400 °C under a nitrogen atmosphere. The results obtained suggest the versatility of the Mn_xCd_ySe-sensitized TiO₂ nanotube matrix as an efficient electrode for photovoltaic applications.