Električni prijenos u molibdenovim i volframovim fosfatnim staklima

doctoral thesis

• Title (english): Electrical transport in molybdenum and tungsten phosphate glasses
• Author: Sanja Renka
• Mentor: Ana Šantić (mentor)
• Committee member: Višnja Vrdoljak (predsjednik povjerenstva)
• Committee member: Marijana Đaković (član povjerenstva)
• Committee member: Jasminka Popović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-12-20, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

U ovoj doktorskoj disertaciji istražen je utjecaj zamjene P2O5 s WO3 i MoO3 na strukturna i električna svojstva binarnih fosfatnih te ternarnih fosfatnih stakala s konstantnim udjelom Li2O odnosno Na2O. Rezultati su pokazali značajno veću polaronsku provodnost WO3‒P2O5 stakala u odnosu na MoO3‒P2O5 stakla kao posljedicu klasteriranja WO6 oktaedara za razliku od MoO6 i MoO4 poliedra koji se uglavnom jednoliko ugrađuju u fosfatnu mrežu. Također je utvrđena važnost terminalnih kisikovih atoma u prijenosu polarona čiji nedostatak uzrokuje smanjenje električne provodnosti. U staklima s Li2O i Na2O utvrđen je učinak miješanih staklotvoraca uslijed nastajanja miješanih volframovih/molibdenovih-fosfatnih jedinica koje ubrzavaju prijenos litijevih i natrijevih iona kroz staklenu mrežu. Za razliku od stakala s Na2O, gdje je uočen maksimum DC provodnosti dodatkom WO3 i MoO3, u staklima s Li2O dobiven je porast provodnosti u cijelom području sastava zbog manjeg radijusa iona litija i posljedično njegove lakše difuzije

Abstract (english)

This doctoral thesis investigates changes in structural and electrical properties occurring upon the replacement of P2O5 by WO3 and MoO3 in binary and ternary phosphate glasses containing constant Li2O and Na2O content. Significantly higher electrical conductivity of WO3‒P2O5 in comparison to MoO3‒P2O5 glasses was ascribed to the clustering of WO6 octahedra in contrast to MoO6 and MoO4 polyhedra which interconnect uniformly with phosphate network. The role of terminal oxygen atoms in polaron conduction was established and shown to be a key parameter which governs the polaron transport. Glasses containing Li2O and Na2O exhibited mixed glass former effect in which the formation of mixed tungsten/molybdenum-phosphate units facilitates the long-range mobility of lithium and sodium ions. In glasses with Na2O, the maximum in DC conductivity was observed, while glasses with Li2O showed increase in the whole compositional range due to the smaller radius of lithium ions and hence their easier diffusion.

• Keywords: fosfatna stakla; električna svojstva; struktura; učinak miješanih staklotvoraca
• Keywords (english): electrical properties; mixed glass former effect; phosphate glasses; structure
• Language: croatian
• URN:NBN: urn:nbn:hr:217:069649
• Promotion: 2023
• Project: Number: IP-2018-01-5425; Title: Detaljan uvid u mehanizme polaronske i ionske vodljivosti u oksidnoj staklo-(keramici); Acronym: POLAR-ION-GLASS; Leader: Ana Šantić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 174 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2023-12-16
• Created on: 2023-02-02 10:07:55