| Budget Amount *help |
¥19,890,000 (Direct Cost: ¥15,300,000、Indirect Cost: ¥4,590,000)
Fiscal Year 2013: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2012: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
Fiscal Year 2011: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000)
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| Research Abstract |
In order to clarify the nonradiative process that dominates luminescence quantum efficiency of inorganic phosphor materials, we have developed a photoconductivity measurement system as functions of temperature and irradiating wavelength. Attention was paid on rare-earth doped phosphor materials for white LED, where 4f-5d electronic transition plays important role. By measurement of temperature dependence of photocurrent excitation spectra, the energy relation of Ce3+:5d level and conduction band of host was investigated for garnet ceramic phosphors of various compositions. A photo-ionization process of excited 5d electrons was found to be a quenching mechanisms at higher temperatures.
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