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Džad-Ofelt-ova teorija i termometrija europiumom dopiranih materijala

dc.contributor.advisorDramićanin, Miroslav
dc.contributor.otherStojadinović, Stevan
dc.contributor.otherBelča, Ivan
dc.creatorĆirić, Aleksandar
dc.date.accessioned2020-06-23T12:16:13Z
dc.date.available2020-06-23T12:16:13Z
dc.date.available2020-07-03T09:51:41Z
dc.date.issued2019-05-27
dc.identifier.urihttp://eteze.bg.ac.rs/application/showtheses?thesesId=7432
dc.identifier.urihttps://nardus.mpn.gov.rs/handle/123456789/12311
dc.identifier.urihttps://fedorabg.bg.ac.rs/fedora/get/o:21964/bdef:Content/download
dc.identifier.urihttp://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=51957519
dc.description.abstractThe main topic of this research is an extension of the Judd-Ofelt theory, a theoretical model applied to the luminescence thermometry, aimed to evaluate the thermometric figures of merit through Judd-Ofelt intensity parameters. The rather expensive, complicated and lengthy conventional method for evaluating the luminescence intensity ratio thermometric properties of a given material would include recording spectra at various temperatures and subsequent data analysis. This model is capable of finding the best transitions for the given material, or various materials, from a roomtemperature spectra or Judd-Ofelt parameters given in literature. The model is originally developed for Eu3+ doped compounds, but is extended for all lanthanide doped materials from praseodymium to thulium. In turn, in Eu3+ doped compounds, the model is able to predict the dipole strength and radiative transition probability of transitions from 5D1 level, if Judd-Ofelt and luminescence intensity ratio thermometric parameters are known. Such analysis was performed on a TiO2:Eu3+ sample, created by the plasma electrolytic oxidation. Judd-Ofelt analysis requires cumbersome calculations, and calculation by hand on many materials to be tested would pose a practical problem. The solution was to create an application software that would be able to calculate Judd-Ofelt intensity parameters and derived quantities from emission spectra of Eu3+ doped compounds. Written in Java, JOES application software was created and tested on TiO2:Eu3+, ZrO2:Eu3+, and Nb2O5:Eu3+, with various europium concentrations, created by plasma electrolytic oxidation process. Luminescence intensity ratio thermometry was tested on TiO2:Eu3+, ZrO2:Eu3+, and Nb2O5:Eu3+ samples. Temperature of the samples during the spectroscopic measurements was controlled by the custom-made heating/cooling apparatus, consisting of a hot plate, cold plate, a control/power unit, and a RTD reference thermometer. Since plasma electrolytic oxidation is a protective coating method, already widely employed for industrial purposes, the investigated samples obtain an additionalfunctionality of becoming temperature sensors, with possible applications in rotor turbines, or on vehicles for hypersonic flights. Since the photoluminescence properties of materials are investigated, the in-depth analysis is performed on HfO2:Eu3+, prepared by plasma electrolytic oxidation, at various europium concentrations. Morphology, chemical and phase composition was investigated, since the photoluminescence is dependent those material properties. JuddOfelt analysis was performed on the sample, and the obtained parameter values are in accordance with the europium site symmetry. CIE chromaticity coordinates were investigated for all the samples, identifying the material potentials for LED and display purposes, from orange-red to white. HfO2:Eu3+ at low concentrations is a potential white LED phosphor.en
dc.description.abstractGlavni predmet istraživanja je proširenje Džad-Ofelt-ove teorije u vidu teorijskog modela primenjenog na fenomen luminescentne termometrije, sa ciljem predviđanja termometrijskih veličina preko Džad-Ofelt-ovih parametara. Tradicionalni metod za ispitivanje termometrijskih osobina materijala pomoću odnosa intenziteta linija uključuje snimanje spektara na različitim temperaturama i njihovu analizu. Ovaj model ima sposobnost određivanja najboljih elektronskih prelaza za dati mateijal, ili za razne materijale, na osnovu spektra snimljenog na sobnoj temperaturi ili Džad-Ofelt-ovih parametera datih u literaturi. Model, isprva kreiran za Eu3+ dopirane materijale, proširen je na sve materijale dopiranih lantanidima, od prazeodijuma do tulijuma. Za Eu3+ dopirana jedinjenja, model može da predvidi jačinu dipolnih prelaza i verovatnoće prelaza sa 5D1 nivoa, ukoliko su poznati Džad-Ofelt-ovi i termometrijski parametri dobijeni iz metode odnosa intenziteta. Takva analiza je izvršena nad TiO2:Eu3+ uzorku, kreiranom plazmenom elektrolitičkom oksidacijom. Džad-Ofelt-ova analiza zahteva kompleksna izračunavanja, tako da bi ručno računanje nad podacima sa mnogo testiranih materijala predstavljalo praktičan problem. Rešenje je u kreiranju softverske aplikacije koja bi mogla da izračuna Džad-Ovelt-ove parametre i izvedene veličine pomoću emisionih spektara Eu3+ dopiranih materijala. Napisana u Javi, JOES softverska aplikacija je napravljena i testirana na TiO2:Eu3+, ZrO2:Eu3+, i Nb2O5:Eu3+, dopiranim sa više različitih koncentracija europiuma i kreiranih plazmenom elektrolitičkom oksidacijom. “Luminescence intensity ratio” termometrija je testirana na TiO2:Eu3+, ZrO2:Eu3+, i Nb2O5:Eu3+ uzorcima. Temperatura uzoraka tokom spektroskopskih merenja kontrolisana je za tu svrhu napravljenim aparatom za grejanje/hlađenje, koji se sastoji od ploče za grejanje, ploče za hlađenje, kontrolne/naponske jedinice, i otpornog referentnog termometra.Kako je plazmena elektrolitička oksidacija metod koji se u industriji koristi za kreiranje zaštitnih slojeva, ispitani uzorci dobijaju dodatnu funkcionalnost kao temperaturni senzori, sa mogućom primenom na rotoru turbina ili vozilima za hipersonični let. Pošto su ispitivane fotoluminiscentne osobine materijala, detaljna analiza je izvršena nad HfO2:Eu3+, pripremljenim plazmenom elektrolitičkom oksidacijom, sa raznim koncentracijama europiuma. Morfologija, hemijski i fazni sastav je ispitan, pošto fotoluminiscencija pokazuje zavisnost od ovih osobina. Džad-Ofelt-ova analiza je izvršena nad uzorkom, i dobijene vrednosti parametara se slažu sa simetrijom europijuma u kristalnoj matrici. CIELUV koordinate su izračunate za sve uzorke, identifikujući materijale pogodne za LED i primenu za ekrane, od narandžasto-crvenih do belih. HfO2:Eu3+ sa niskim koncentracijama europijuma je potencijalni beli LED fosfor.sr
dc.formatapplication/pdf
dc.languageen
dc.publisherУниверзитет у Београду, Физички факултетsr
dc.rightsopenAccessen
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.sourceУниверзитет у Београдуsr
dc.subjectJudd-Ofelten
dc.subjectDžad-Ofelten
dc.subjectfotoluminiscencijaen
dc.subjecttermometrijaen
dc.subjecteuropiumen
dc.subjectphotoluminescenceen
dc.subjectthermometryen
dc.subjecteuropiumen
dc.titleJudd-Ofelt theory and thermometry of europium doped materialsen
dc.title.alternativeDžad-Ofelt-ova teorija i termometrija europiumom dopiranih materijalaen
dc.typedoctoralThesisen
dc.rights.licenseBY
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/25381/Disertacija.pdf
dc.identifier.fulltexthttps://nardus.mpn.gov.rs/bitstream/id/25381/Disertacija.pdf
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/25382/IzvestajKomisije22531.pdf
dc.identifier.fulltexthttps://nardus.mpn.gov.rs/bitstream/id/25382/IzvestajKomisije22531.pdf
dc.identifier.rcubhttps://hdl.handle.net/21.15107/rcub_nardus_12311


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