Band-gap engineering of novel phosphors with narrow f-f emission

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04714
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Okayama University of Science
• Principal Investigator: Sato Yasushi 岡山理科大学, 理学部, 准教授 (90383504)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 蛍光体 / バンドギャップ制御 / f-f発光 / ランタノイドイオン / 酸窒化物

Outline of Final Research Achievements

We developed the new narrow-band phosphors with f-f emission in order to use some white-LED applications. To realize f-f emissions by rare-earth ions activated phosphors excited by near-UV and blue lights, perovskite oxide-oxynitride solid solutions were used as host compounds. We confirmed that the adjustments of energy gap between valence and conduction bands (Eg) in host compounds enabled us to excite the f-f emission from Pr3+ ions in host lattice by near UV lights. In addition, we investigated the other host compounds with Eg corresponding to near-UV region for the use of narrow-band phosphors with f-f emission. We successfully prepared the high-pure single phase of LaMO2N (M:Zr, Hf) by the heat treatment using ammonia gas with active metals such as Mg and Al. Based on these results, we proposed the new material design for narrow-band phosphors with f-f emission and showed the possibility of the phosphors for the use of white-LED applications.

Free Research Field

無機固体化学

Academic Significance and Societal Importance of the Research Achievements

本研究において実証したホスト物質のバンドギャップ制御を利用した発光イオンの励起とf-f発光制御の試みは、Pr3+による赤色発光だけでなく、Tb3+による緑色発光やTm3+による青色発光にも適用でき、f-f発光型蛍光体のみの組み合わせによる白色光の再現を可能である。よって、本研究での成果は、従来のf-d発光型蛍光体に代わる新しいタイプの白色LED用蛍光体の物質設計法であり、実用化に向けた更なる発展が望まれる。今後の課題として発光強度の向上が挙げられるが、ホスト物質の結晶性向上による改善が予想され、次世代白色LED用蛍光体としての利用が期待できる。