Ordered titanium dioxide nanotubes filled with photoluminescent surfactant-free silicon nanocrystals

The electrophoretic filling of titanium dioxide (TiO2) nanotubes with surfactant-free silicon nanocrystals (Si-ncs) dispersed in ethanol and the water is shown. We illustrate a simple and scalable room temperature approach that allows natural selection and deposition of the smallest-supernatant Si-ncs on TiO2 nanotubular template. The anatase TiO2 nanotubes with diameters of 50 nm were used to template Si-ncs with a higher (> 10 times) deposition rate of Si-ncs dispersed in ethanol. Lower agglomeration in ethanol and the deposition of Si-ncs with smaller diameter deeper inside the TiO2 nanotube resulted in a redshift of the photoluminescence maximum of about 60 nm. A potential application of the room temperature photoluminescent Si-ncs/TiO2 nanocomposite for hybrid solar cells is demonstrated. Enhanced Si-ncs electrophoretic deposition in ethanol improved both the open-circuit photovoltage and short-circuit photocurrent.