Term of Award

Fall 2024

Degree Name

Master of Science, Applied Physical Science

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Chemistry and Biochemistry

Committee Chair

José A. Jiménez

Committee Member 1

Rafael Quirino

Committee Member 2

Rocio Perez

Abstract

Ytterbium(III)-doped glasses are widely known for their application in near-infrared (NIR) lasers and nowadays attract attention for solar spectral conversion in photovoltaic cells. In this study, the effects of ytterbium(III) concentration on the physical, structural, optical, and thermal characteristics of Yb-doped phosphate glasses were investigated. The glasses were synthesized using the melt-quenching technique with nominal compositions of 50P2O5:(50 – xBaO):xYb2O3 (x = 0, 0.5, 1.0, 2.0, 3.0 and 4 mol%). The properties were then examined by density and related parameters, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared (FT-IR) spectroscopy, Raman spectroscopy, differential scanning calorimetry (DSC), dilatometry, optical absorption, and photoluminescence (PL) spectroscopy. From the analysis of the results obtained through the previous techniques, it was observed that the density slightly decreased initially relative to the undoped glass but ultimately increased for high Yb2O3 content. The average molar volume increased with an increase in Yb2O3 content whereas the XRD confirmed the amorphous nature of the glasses. Oxygen speciation by XPS providing information on bridging and non-bridging oxygen did not support depolymerization with increasing Yb2O3 content. The FT-IR evaluation indicated a shift to high frequency with increasing ytterbium content which was discussed in terms of high field strength of Yb3+ ions. The Raman spectra showed some broadening and shifting in bands position and were discussed in terms of the high filed strength of the Yb3+ ions. From the DSC assessment, the glass transition temperature, onset of crystallization, and crystallization temperatures increased with increasing Yb2O3 content. Dilatometry analysis showed a decrease in the coefficient of thermal expansion and an increase in the softening temperature with increasing Yb2O3 concentration. From the NIR spectra the absorption intensity increased with high Yb2O3 content. However, the PL assessment showed the NIR emission intensity increased up to 2 mol% Yb2O3 and decreased afterwards. Emission decay curves were also analyzed to understand the PL quenching. Concentration effects based on data from the various techniques used in this study highlight the structure-property connections of the ytterbium(III)-doped glasses attractive for optical applications.

OCLC Number

1478254839

Research Data and Supplementary Material

No

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