희토류 원소 첨가 비정질 찰코지나이드;형광 수명과 유리 구조 변화의 관계 = Amorphous Chalcogenide Solids Doped with Rare-Earth Element:Fluorescence Lifetimes and the Glass Structural Changes

다국어 초록 (Multilingual Abstract)

Lifetime of excited electronic states inside the 4f configuration of rare-earth elements embedded in chalcogenide glasses is very sensitive to medium-range structural changes of the host glasses. We have measured lifetimes of the 1.6 m emission originating from Pr3+: (3F3, 3F4) 3H4 transition in amorphous chalcogenide samples consisting of Ge, Sb and Se elements. The measured lifetimes turned out to have their maximum at the mean coordination number of ~2.67, which arises accordingly from structural changes of the host glasses from 2 dimensional layers to 3 dimensional networks. This new finding supports that the so-called topological structure model together with chemically ordered network model is adequate to explain relationship between the emission properties of rare-earth elements and the medium-range structures of amorphous chalcogenide hosts with a large covalent bond nature. Thus, it is validated to predict site distribution and lifetime of rare-earth elements doped in chalcogenide glasses simply based on their mean coordination number.

국문 초록 (Abstract)

찰코지나이드 유리에 첨가된 희토류 원소의 4f 전자 궤도를 구성하는 여기 상태 에너지 준위의 수명은 기지 재료의 단거리 구조 변화뿐만 아니라 중거리 구조 변화에도 매우 민감하다. Pr3+ 이온을 첨가한 다양한 조성의 Ge-Sb-Se 계열 찰코지나이드 샘플을 대상으로 Pr3+: (3F3, 3F4) 3H4 천이로부터 발생하는 1.6 m 형광의 수명을 측정한 결과, 해당 형광 수명은 mean coordination number가 ~2.67이 되는 조성에서 최대값을 나타내었다. 이는 유리의 구조가 2차원 구조에서 3차원 구조로 전환됨에 따라 희토류 이온의 분포도가 변화하기 때문이며 소위 topological structure 모델과 chemically ordered network 모델로써 공유 결합성이 강한 찰코지나이드 유리에 첨가된 희토류 이온의 발광 특성에 대한 해석이 가능하였다. 이러한 결과는 희토류 원소의 분포 및 형광 수명을 단지 찰코지나이드 재료의 성분비만으로 예측할 수 있다는 새로운 관점이 타당함을 의미한다.

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