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Printing of up-conversion marks
Azariová, Viktória ; Ďurovič, Michal (referee) ; Veselý, Michal (advisor)
The subject of this these is a preparation and printing of upconversion marks that have been printed by two printing techniques, namely screen printing and pad printing. The makrs were designed to visualize another chemical code identifiable by instrumentation. The impact of chemical code components on the fluorescence intensity of upconversion marks and the impact of individual components on printability and print sustainability were studied. The upconversion pigment was excited by NIR laser.
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Laser spectroscopy of semiconductor quantum dots
Pokorný, Martin
This work is focused on examining photoluminescent properties of InAs quantum dots (QDs) on GaAs substrate covered by GaAs1-xSbx strain reducing capping layer (SRL) prepared by Stranski-Krastanow method. We measured luminescence decay time of two samples with different concentration of Sb in this layer. We investigated the influence of temperature, intensity and wavelength of the excitation pulse on the luminescent decay time. We also compared the properties of the samples after excitation by 760 nm pulse and 850 nm pulse - the former one is energetically above the substrate band gap; in the second case we excited only the QDs and the wetting layer (WL). We consequently derived recombination and relaxation processes occurring inside InAs QDs and also the transport of charge carriers from the substrate and the WL into QDs. One part of this diploma thesis was to learn about the methods of measuring ultrafast photoluminescence and build the experimental set-up.
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Printing of up-conversion marks
Azariová, Viktória ; Ďurovič, Michal (referee) ; Veselý, Michal (advisor)
The subject of this these is a preparation and printing of upconversion marks that have been printed by two printing techniques, namely screen printing and pad printing. The makrs were designed to visualize another chemical code identifiable by instrumentation. The impact of chemical code components on the fluorescence intensity of upconversion marks and the impact of individual components on printability and print sustainability were studied. The upconversion pigment was excited by NIR laser.
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Design and characterization of advanced polymer-coated upconversion nanoparticles
Kostiv, Uliana ; Horák, Daniel (advisor) ; Kaman, Ondřej (referee) ; Brožek, Jiří (referee)
Lanthanide-based upconversion nanoparticles are able to absorb low-energy near-infrared (NIR) photons and emit visible or ultraviolet light. This unique optical property enables luminescent detection without autofluorescence from biological samples that is crucial for bioimaging and diagnostics. Moreover, NIR irradiation allows to deliver light deep into the tissue, which can be used for drug or gene delivery and NIR-induced photodynamic therapy (PDT) of tumors. Despite huge effort during the last 10 years devoted to the upconversion nanoparticle synthesis and their surface engineering, preparation of the particles suitable for biomedical applications still remains a big challenge. The current work is focused on synthesis of the upconversion nanoparticles with controllable morphology, size, distribution, crystallinity, and high upconversion efficiency, as well as on desirable surface modification by biocompatible inorganic or organic polymers. Neat and functionalized homogeneous silica shell was introduced on the NaYF4:Yb3+ /Er3+ and NaGdF4:Yb3+ /Er3+ nanoparticles to enhance their biocompatibility and colloidal stability in water. To render the nanoparticles with targeting moieties, their surface was decorated with cell-adhesive RGD or cell-penetrating TAT peptides. The RGD- and TAT- conjugated...
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Laser spectroscopy of semiconductor quantum dots
Pokorný, Martin
This work is focused on examining photoluminescent properties of InAs quantum dots (QDs) on GaAs substrate covered by GaAs1-xSbx strain reducing capping layer (SRL) prepared by Stranski-Krastanow method. We measured luminescence decay time of two samples with different concentration of Sb in this layer. We investigated the influence of temperature, intensity and wavelength of the excitation pulse on the luminescent decay time. We also compared the properties of the samples after excitation by 760 nm pulse and 850 nm pulse - the former one is energetically above the substrate band gap; in the second case we excited only the QDs and the wetting layer (WL). We consequently derived recombination and relaxation processes occurring inside InAs QDs and also the transport of charge carriers from the substrate and the WL into QDs. One part of this diploma thesis was to learn about the methods of measuring ultrafast photoluminescence and build the experimental set-up.
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Laser spectroscopy of semiconductor quantum dots
Pokorný, Martin ; Trojánek, František (advisor) ; Kuldová, Karla (referee)
This work is focused on examining photoluminescent properties of InAs quantum dots (QDs) on GaAs substrate covered by GaAs1-xSbx strain reducing capping layer (SRL) prepared by Stranski-Krastanow method. We measured luminescence decay time of two samples with different concentration of Sb in this layer. We investigated the influence of temperature, intensity and wavelength of the excitation pulse on the luminescent decay time. We also compared the properties of the samples after excitation by 760 nm pulse and 850 nm pulse - the former one is energetically above the substrate band gap; in the second case we excited only the QDs and the wetting layer (WL). We consequently derived recombination and relaxation processes occurring inside InAs QDs and also the transport of charge carriers from the substrate and the WL into QDs. One part of this diploma thesis was to learn about the methods of measuring ultrafast photoluminescence and build the experimental set-up.
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