Type-II Heterojunctions in SnO2-Coated TiO2 Core-Shell Nanoparticles
Abstract
Titanium dioxide (TiO2) and tin oxide (SnO2) are two popular wide band-gap semiconductors for photocatalytic and electronic applications such as solar cells, optoelectronic devices, and lithium-ion batteries. Nanosized TiO2 structures have strong absorption in the UV region while SnO2 is a powerful transparent conducting oxide. Composites of TiO2 and SnO2 are especially attractive since they form a type-II heterojunction extending the lifetime of charge carriers and enhancing photoconversion efficiency. In this study, the synthesis of TiO2 nanoparticles as well as their uniform and controlled coating with SnO2 shells are described, providing the first utilization of sodium stannate to grow SnO2 shells on a metal-oxide core. The step-growth method utilized here shows the ability to vary the shell thickness between 5-40 nm while maintaining uniformity of the shell. As such, the complete synthesis route involves facile and reproducible surfactant-free solution-based methods at moderate temperatures. The nanoparticles were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Overall, this paper represents reliable nanoscale fabrication techniques offering key advancements in photovoltaic and optoelectronic applications. Keywords: TiO2, SnO2, Heterojunction, Core-shell, Nanoparticles, Wide Band-gap Semiconductor
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 01, 2021
- Source ID
- 10.33790/crmc1100112
Entities
People
- Nhat M. Ngo
- Riddhiman Medhi
- T. Randall Lee
- Tai-Chou Lee
Organizations
- Air Force Office of Scientific Research
- Robert A. Welch Foundation
- Texas Center for Superconductivity