Conduction mechanisms in gas detectors based on nanostructured metalic oxide semic...
| Grant number: | 17/12437-5 |
| Support type: | Regular Research Grants |
| Duration: | October 01, 2017 - September 30, 2019 |
| Field of knowledge: | Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials |
| Principal Investigator: | Luís Fernando da Silva |
| Grantee: | Luís Fernando da Silva |
| Home Institution: | Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil |
Abstract
Gas sensor devices display a variety of applications, ranging from environmental monitoring to healthcare. The main attractive of these devices, in the healthcare, is the possibility of performing noninvasive diagnosis of some diseases. Diabetes is a lifelong condition that may cause death and seriously affects the quality of life of a rapidly growing number of peoples. Acetone is a selective human breath marker for diabetes, thus, gas sensors have been used in detection of acetone in breath. Among the materials for acetone gas sensing, SnO2 and Fe2O3 have been considered promising. However, the high operating temperatures (150 a 500 oC) of these sensors make their applications difficult. The UV photoactivation of these sensors has been an efficient way to use these devices at room-temperature. Nevertheless, the electronic effects adverse during the charge separation process reduce the sensors performance. Heterostructures have been investigated as simple and alternative way to reduce the recombination process. Despite their potential, few papers have reported the influence of UV irradiation on the heterostructures gas sensing performance. In this way, the general purpose of this project will be establish a new laboratory in the department of physics at the Federal University of São Carlos (UFSCar) devoted for investigation of semiconductor heterojunctions applied as photoactivated gas sensors. To attain this objective, we will prepare SnO2 and Fe2O3 nanostructures and Fe2O3/SnO2 heterojunctions for investigation as UV-activated gas sensor. The samples will be synthesized via nonaqueous Sol-gel route, which enables a controlled and reproductive preparation of these materials. Electrical DC measurements will be performed with and without UV-light radiation using oxidizing and reducing gases for evaluation of the gas sensing performance. Furthermore, we also propose an investigation "in-situ e operando" by using AC impedance spectroscopy to understand the role of different regions of the device (electrodes, bulk, and grain boundaries) involved in the gas sensing mechanism of the synthesized samples. (AU)