Multinuclear solid-state NMR spectroscopy: An approach between the structure and the properties of new material

• Grant number: 23/07718-6
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2025
• End date: May 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Silvia Helena Santagneli
• Grantee: Silvia Helena Santagneli
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated researchers: Jeferson Almeida Dias

Abstract

The main objective of this proposal is to conduct a structural study of disordered materials by Solid-state Nuclear Magnetic Resonance. The aim is to develop and study new disordered materials based on silicate and phosphates obtained via the sol-gel and melting quenching process. These materials have potential applications in optical and electrical devices. The interest in these systems is based on the structural understanding of the hydrolysis and condensation reactions involved in the sol-gel and melting quenching methodology, as well as the thermal treatment process to obtain glasses and glass-ceramics with excellent optical, electrical and physical-chemical properties, such as homogeneity, chemical stability, and high transparency in the visible and infrared region and glass-ceramics with high electrical conductivity. Obtaining homogeneous glasses is essential, specifically for Si-Al-P-based glass system, where the control of P and Al concentrations are required, as well as in the hydrolysis and condensation processes. The addition of low concentrations leads to Al2O3 clusters formation and phosphate loss. Ionic conductive phosphate-based glasses are obtained with optimal characteristics for the production of ion-conducting glass ceramics, allowing the correlation of composition and structural evolution through the advancement of heat treatment. In this context, NMR is a comprehensive integrated spectroscopic strategy for providing short and medium-range information on the formed structure. In this proposal, the development of new materials can be divided into two lines of research: i) obtaining glasses based on Si-Al-P doped with Er3+ and bismuth ions via sol-gel methodology, followed by heat treatment, with high homogeneity and optical quality for application in amplifiers in telecommunications systems. The telecommunications system contains four windows (E, S, C and L), from 1.36 to 1.65 ¿m. However, the width from 1.45 to 1.65 ¿m (S+C+L bands) is the most widely used, due to the low optical loss of silica fibers and ii) obtaining glass precursor of NASICON system (sodium ion superconductors) by melting quenching methodology, on the formation of the phases and electrical properties of the corresponding glass ceramics. Likewise, understanding structural evolution with the advancement of NMR heat treatment will allow the production of glass ceramics from the NASICON system with optimal electrical properties, allowing the selection of the best compositions and heat treatment conditions to produce materials for use in storage energy. (AU)