オートクレーブを利用したゾル-ゲルガラス封止Eu錯体の信頼性向上＜論文＞

概要

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Optical degradation characteristic of Eu-complex is one of the most important problems to solve for practical white light-emitting diodes. Eu-complex generates bright red emission by the ultraviolet (UV) irradiation; however, it is easily decomposed by reacting oxygen and vapor when the UV light is irradiated. Therefore the photoluminescence (PL) intensity was reduced by irradiating UV light. In this paper, we demonstrated the drastic improved long term stability by annealing in an autoclave container compared to a conventional annealing in an electric furnace. By optimizing the concentration of starting solution of sol-gel process and the annealing temperature, the PL intensity change of Eu-complex was reduced. In addition, the PL quantum yield of encapsulated sample was almost same as that of Eu-complex without the encapsulation. The most likely cause is that the dense glass network was formed around Eu-complex during the high pressure annealing. These results indicate the autoclave process is useful technique to improve the optical degradation characteristics, and the practical long term stability will be realized in a near future by optimizing the fabrication condition.
埼玉大学工学部の論文