Characterization of Electrical and Photoluminescent Properties of SnO2/WO3 Nanoheterostructures

• Grant number: 24/13181-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2024
• End date: August 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Luís Fernando da Silva
• Grantee: Enzo Lucas Breancini Coelho Barros
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 22/02927-3 - Gas sensors based on n-type semiconductors operating at room temperature: investigation of their performance and mechanisms involved, AP.PNGP.PI

Abstract

Resistive gas sensors are increasingly being used in our daily lives. Semiconducting metal oxides (MOXs) are an important class of multifunctional materials in the field of materials physics. Among these MOXs applied as resistive sensors for toxic gases, the WO3 and SnO2 compounds have exhibited potential performance. Although promising, the relatively high operating temperatures (>150oC) of these sensor materials have hindered practical applications. Among the strategies investigated, the use of heterostructured materials (combination of two different semiconductors) has contributed significantly to the formation of active sites, favoring their sensing activities. Gas sensors based on heterostructures have also made it possible to reduce their operating temperature, in some cases working efficiently at room temperature when subjected to UV light irradiation (photostimulation). Motivated by these considerations, in this project we propose the preparation and characterization of SnO2/WO3 nanoheterostructures obtained by the polymer precursor method. The samples will be characterized by conventional and advanced techniques such as X-ray diffraction, photoluminescence spectroscopy, electron microscopy (SEM and HRTEM), and X-ray photoelectron spectroscopy (XPS). In addition, "in-situ and operating" analyses will be carried out using the photoluminescence spectroscopy technique. These analyses will make it possible to assess the degree of order associated with the disorder imposed on the sensor material when exposed to a given atmosphere (e.g. oxidizing or reducing). The intensity of the spectra can be related to the degree of recombination of the charge carriers, making it possible to understand the electronic properties of the sensor samples. At the same time, DC electrical measurements will be carried out, providing useful information on the sensing performance of the samples, allowing them to be correlated with their photoluminescent properties.