2006 Fiscal Year Final Research Report Summary
Development of high-brightness phosphors with quantum yield > 1
| Project/Area Number |
17560007
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | SHINSHU UNIVERSITY |
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Principal Investigator |
ITOH Minoru Shinshu University, Faculty of Engineering, Professor, 工学部, 教授 (80126664)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Optical property / Phosphor / Quantum yield / Luminescence / Time-resolved measurement / Synchrotron radiation / High-brightness / Two-photon emission process |
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| Research Abstract |
In modern society, a great deal of information necessary for everyday life is processed and memorized in electronic devices such as computers, and we cannot see it directly. Display devices, which visualize the memorized information on the screen, are widely used as an interface between humans and computers. They also play an important role for home entertainment. A high reliability of the screen image, which is determined by the brightness, resolution, contrast, speed and legibility, prevents eye fatigue, and is deeply required for advanced display devices.
Phosphor particles are the most important element for the display devices. In the present work, we focus our efforts on a new type core-valence luminescence. This is called "Auger-free luminescence (AFL)." In the emission process of AFL, two photons are emitted under one-photon excitation process of the outer-most core band ; i.e., two-step cascade process takes place efficiently. This leads to high brightness ; it is expected that the quantum yield is more than 1.
Many materials emitting AFL are investigated by using synchrotron radiation from UVSOR storage ring in Okazaki. The decay dynamics of AFL is also examined. Furthermore, their time-resolved luminescence spectra are measured under the excitation with a Nd : YAG laser. From these data, emission centers and lattice imperfections are clarified. The obtained results will play a significant role for the development of high-brightness phosphors.
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