Synthesis and characterization of new phosphors and clarification of its mechanism

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06721
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Inorganic materials/Physical properties
• Research Institution: Toyohashi University of Technology
• Principal Investigator: Nakano Hiromi 豊橋技術科学大学, 教育研究基盤センター, 教授 (00319500)
• Research Collaborator: MABUCHI mamoru ; FURUTA yoshio
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 蛍光体 / 発光特性 / 結晶構造制御 / 組織制御 / 加圧ガス雰囲気炉 / 低温・短時間合成手法 / 固相反応法 / XAFS

Outline of Final Research Achievements

We have been investigating new phosphors from the viewpoint of processing and characterization. New phosphors with a composition of a Li-(Ta,Nb)-Ti-O system were investigated using an electric furnace or air-pressure control atmosphere furnace. We succeeded in synthesizing the Li-Nb-Ti-O ceramic rapidly using an air compressor. The biggest grain was obtained under 0.35 Mpa and the value is 3.5 times higher with air pressure than atomospheric pressure. From EELS, TEM and XAFS data, the interstitial oxygen can promote oxygen diffusion with a combination of vacancies along the intergrowth layer.
New phosphors of P doped Ca2SiO4 with Eu ion as an activator were investigated. The relationship between PL property and crystal structure was clarified by XAFS, XRD, and TEM. The polymorphs of C2S are γ, β, α’L, α’H, and α in the order of increasing temperature. The Eu ion was occupied in the Ca site and the environmental conditions could be controlled variously by the phase transition.

Free Research Field

無機材料分野

Academic Significance and Societal Importance of the Research Achievements

市場規模の大きい白色LED産業分野において、今回の研究により得られた、「新規蛍光体の設計に関する知見」は、より発光効率のよい蛍光体の開発につながるものであり、我々の暮らしを豊かにし、省エネルギー社会にも貢献する。また、色純度の高い赤色蛍光体は、プロジェクター、スマホバックライトなど、日常生活をより快適にするものである。本研究は、原子スケールで結晶構造を制御し、発光特性との関係性を詳細に研究したものであり、得られた新知見は、学術的にも、産業界においても意義ある成果である