Luminescent silicates as chemical sensors

• Grant number: 06/06972-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2007
• End date: September 30, 2007
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Ana Maria Pires
• Grantee: Mauro Anísio da Silva Ribeiro
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

Luminescent materials are usually used as image devices. In the case of Ba2SiO4:Eu, the Eu2+ is stabilized under reduction atmosphere in Ba(II) sites and shows blue emission; on the other hand, under no reduction atmosphere, europium ion remains as Eu(III) (red emitter), whereas a charge compensating mechanism takes place generating Eu(III)-O2- associates. In the field of chemical sensors, the development of modified chemically electrodes has been increasing in order to identify analytes from their interaction with systems that involves oxidation state displacement. During electrode building the specie that should be sensitive towards the analyte must be incorporated in such electrode as a homogeneous film. Therefore, the aim of this work is the investigation of luminescent systems of matrices based in silicates suitable for the stabilization of divalent metals as well as Eu(III) as doping ion. Previous measurements of Ba2SiO4:Eu prepared by solid state reaction indicated the presence of both Eu(II) and (III) species which are easily spectroscopically identified. In that way this system is promising for tests as electrode surface modifier for the identification of analytes of environmental and pharmaceutical application.