Search for dissertations about: "phosphor materials"

Showing result 1 - 5 of 13 swedish dissertations containing the words phosphor materials.

2. 1. Dynamic local structural symmetries and luminescence properties of the yellow emitting phosphor Ce3+-doped Y3Al5O12

   Author : Yuan-Chih Lin; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; neutron scattering; vibrational spectroscopy; phosphor; light emitting diode; luminescence; thermal quenching; garnet;

   Abstract : This thesis centers on investigations of the local structure and vibrational properties of the oxide garnet Y3Al5O12 (YAG), which when substituted with a few percent of the activator ion Ce3+ to replace Y3+ (Y3−xCexAl5O12, YAG:Ce3+) is one of the most important phosphors for solid state lighting. The study builds on a comprehensive analysis of the nature of the phonons and localized vibrational modes in YAG:Ce3+ and how these depend on the Ce3+ concentration and temperature and how they affect key optical properties, such as the intensity and frequency of the emitted light. READ MORE

4. 2. On the surface quality of continuously cast steels and phosphor bronzes

   Author : Saud Saleem; Hasse Fredriksson; Michael Vynnycky; Toshihiko Emi Takaido Higashi; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Continuous Casting; Steels; Ni-based alloy; Peritectic; Phosphor Bronzes; Simulation and Modeling; Teknisk materialvetenskap; Materials Science and Engineering; Industriell ekonomi och organisation; Industrial Engineering and Management; Metallurgical process science; Metallurgisk processvetenskap;

   Abstract : This thesis work concerns about the importance of the cast surfaces, surface phenomenon such as the formation of the oscillation marks and exudation and related defects including cracks and segregation that happened during the continuous casting. All of the investigated materials were collected during the plant trials while an in-depth analysis on these materials was performed at the laboratory scale with certain explanations supported by the schematic and theoretical models. READ MORE

5. 3. Laser-Induced Emission Techniques for Concentration and Temperature Probing in Combustion

   Author : Gustaf Särner; Förbränningsfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; thermographic phosphor; phosphor; phosphorescence; Laser Combustion Diagnostics; Laser-Spectroscopy; LIF; spectroscopy; Thermometry; LIP; Laser-Induced Fluorescence;

   Abstract : The work in this thesis is aimed at the development of temperature and gas concentration measurement techniques in laser diagnostics for use in combustion research. The techniques are developed as tools for the combustion community to meet future demands on combustion efficiency and legislation of exhaust gases. READ MORE

6. 4. Live long and phosphor : synthesis of new 2,1,3-benzothiadiazole based scaffolds and novel organo-Au(I) luminophores

   Author : Mauricio Posada Urrutia; Christine Dyrager; Sascha Ott; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemistry with specialization in Organic Chemistry; Kemi med inriktning mot organisk kemi;

   Abstract : 2,1,3-Benzothiadiazole (BTD) has arisen as a scaffold of interest to a variety of fields including materials chemistry and medicinal chemistry. It is utilized in the development of light emitting materials, solar-cells, and batteries. READ MORE

7. 5. Understanding the interactions between vibrational modes and excited state relaxation in garnet structured phosphors

   Author : Yuan-Chih Lin; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; thermal quenching.; luminescence; garnet; vibrational spectroscopy; neutron scattering; phosphor; light emitting diode;

   Abstract : This thesis concerns investigations of the local structural environments and vibrational dynamics of the three garnet type oxide phosphors Ce3+-doped Y3Al5O12 (YAG:Ce3+), Ca3Sc2Si3O12 (CSS:Ce3+), and Sr3Y2Ge3O12 (SYG:Ce3+), which show promising optical properties as luminescent materials used in solid state white lighting technologies. The study focuses on a comprehensive analysis of the nature of the long-range vibrations (phonons) in terms of local atomic and molecular motions of the garnet structure, as well as their dependence on the nature of the garnet chemical composition, Ce3+ concentration and temperature. READ MORE