Visible light photoluminescence in TiO2/CdS nanopowders synthesized by sol-gel route: effect of gel aging time

E.S Ulyanova,E.V Shalaeva,V.Yu Kolosov,D.A Zamyatin

doi:10.17586/2220-8054-2020-11-4-480-487

E.S Ulyanova, E.V Shalaeva + Show 2 more

Open Access

https://doi.org/10.17586/2220-8054-2020-11-4-480-487

Copy DOI

Abstract

Visible light photoluminescence in TiO2/CdS nanopowders synthesized by sol-gel route: effect of gel aging time

Highlights

Semiconductor TiO2/CdS composites represent an important group of visible-light photoactive materials and are attracting considerable attention due to the fact that cadmium sulfide has a relatively narrow band gap and is well combined with the band structure of titanium dioxide [1,2,3]
The aim of work is to elucidate the effect of gel aging time on visible PL emission in TiO2/CdS composites prepared by sol-gel route using pre-synthesized CdS nanoparticles and gel aging stage at boiling point
The drop in the concentration of CdS nanoparticles is associated with the decreases in the content of the amorphous phase in the TiO2 matrix and the calculated thermodynamic stability of the composite CdS @ TiO2 nanoparticles depending on the structure of the titanium shell: amorphous titania > polycrystalline titania

Summary

Introduction

Semiconductor TiO2/CdS composites represent an important group of visible-light photoactive materials and are attracting considerable attention due to the fact that cadmium sulfide has a relatively narrow band gap and is well combined with the band structure of titanium dioxide [1,2,3]. Technique for producing photoactive composites TiO2/CdS was proposed, based on a modified sol-gel method using pre-synthesized CdS colloidal nanoparticles and low-temperature gel aging stage at boiling point [24]. As has been shown, can affect the crystallinity degree of titania (amorphous/nanocrystalline ratio), and content of the incorporated CdS nanoparticles [25]. The aim of work is to elucidate the effect of gel aging time on visible PL emission in TiO2/CdS composites prepared by sol-gel route using pre-synthesized CdS nanoparticles and gel aging stage at boiling point. It was concluded that the surface defects of TiO2 and content of the incorporated CdS nanoparticles predominantly affect the visible emission, unlike the crystallinity degree of titania. A TiO2/CdS composite with suppressed visible PL emission was found to exhibit the enhanced visible light photoactivity

Experimental part

Results and discussion

Conclusions