Processing of upconverter glasses with persistent luminescence
Lahti, Vilma (2020)
2020
Tekniikan ja luonnontieteiden kandidaattiohjelma - Bachelor's Programme in Engineering and Natural Sciences
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2020-11-27
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202011178048
https://urn.fi/URN:NBN:fi:tuni-202011178048
Tiivistelmä
The objective of this project was to prepare and investigate rare-earth doped glasses with persistent luminescence.
Glasses with the composition (100 - 0.25 - x) (75NaPO3 – 25CaF2) – 0.25Er2O3 – x(Fe2O3 / Al2O3 / MgO) with x = 0 (labelled Ref), x = 0.5 for Fe2O3 and Al2O3 (labelled Fe and Al) and x = 3 for MgO (labelled Mg) (in mol%) were prepared with 0.5 wgt% of commercial microparticles with persistent luminescence (PeL) using the direct doping method. After annealing, the glasses were heat treated in order to check if the addition of the PeL in the glass has an impact on the volume precipitation of Er3+ doped CaF2 crystals in the volume of the glasses.
The persistent luminescent particles survived the melting as evidenced by the strong green afterglow from the glasses after stopping UV irradiation. Intensity of the afterglow decreased with the increase of doping temperature indicating that the PeL particles partially degrade in the glass during the glass preparation. Analysing the XRD patterns of the heat-treated glasses, it was discovered that Ref and Al samples contained CaF2 crystals after heat treatment, but Fe and Mg did not. Therefore, the heat treatment of the Ref and Al glass leads to strong increase in the intensity of the upconversion.
With this project, we showed that the partial degradation of the PeL particles in the glass has no significant impact on the nucleation and growth process of the glass. However, due to the long melting process in the direct doping method, large amount of F is suspected to evaporate reducing the amount of CaF2 crystals precipitating in the glasses.
Glasses with the composition (100 - 0.25 - x) (75NaPO3 – 25CaF2) – 0.25Er2O3 – x(Fe2O3 / Al2O3 / MgO) with x = 0 (labelled Ref), x = 0.5 for Fe2O3 and Al2O3 (labelled Fe and Al) and x = 3 for MgO (labelled Mg) (in mol%) were prepared with 0.5 wgt% of commercial microparticles with persistent luminescence (PeL) using the direct doping method. After annealing, the glasses were heat treated in order to check if the addition of the PeL in the glass has an impact on the volume precipitation of Er3+ doped CaF2 crystals in the volume of the glasses.
The persistent luminescent particles survived the melting as evidenced by the strong green afterglow from the glasses after stopping UV irradiation. Intensity of the afterglow decreased with the increase of doping temperature indicating that the PeL particles partially degrade in the glass during the glass preparation. Analysing the XRD patterns of the heat-treated glasses, it was discovered that Ref and Al samples contained CaF2 crystals after heat treatment, but Fe and Mg did not. Therefore, the heat treatment of the Ref and Al glass leads to strong increase in the intensity of the upconversion.
With this project, we showed that the partial degradation of the PeL particles in the glass has no significant impact on the nucleation and growth process of the glass. However, due to the long melting process in the direct doping method, large amount of F is suspected to evaporate reducing the amount of CaF2 crystals precipitating in the glasses.
Kokoelmat
- Kandidaatintutkielmat [10016]