Highlighting the importance of optimal defect density through band structure and photocatalytic studies

Interface energetics plays a substantial role in the efficient charge transfer between semiconductor materials. The concentration of donors or acceptors at the junction determines the direction of charge flow. In this work, CdS was doped to TiO2 progressively to explore the electronic structure modification and its associated effect on charge dynamics. Results suggest that loss of dipole moment with increasing CdS concentration; causing the work function (WF) values of the composites to increase. The dipole-dipole repulsion occurs as a consequence of a decrease in Cd-Cd distance at higher doping concentrations. When present in optimal concentration, the surface dipoles besides aiding in efficient charge transfer, accelerate the chemisorption process at corrugated surfaces. Apart from the optoelectronics, efforts have been made to understand the hindering role of higher defect concentration in triggering the thermodynamically favored undesired photocatalytic reactions, which drastically reduce the quantum yield of the process. This work may provide some insights to tune the work function (WF) values in applications that involve optoelectronic and photocatalytic studies.

Automated summary

The study explores the modification of electronic structure and its impact on charge dynamics when gradually doping CdS into TiO2, finding that the composite's work function values increase with higher CdS concentration. Additionally, CdS doping causes a decrease in Cd-Cd distance, resulting in dipole-dipole repulsion. Surface dipoles at optimal concentration not only aid in efficient charge transfer but also accelerate the chemisorption process on corrugated surfaces.