Enhanced Red Emission in CaMoO4:Bi3+,Eu3+

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• 作者：Suxia Yan ; Jiahua Zhang ; Xia Zhang ; Shaozhe Lu ; Xinguang Ren ; Zhaogang Nie ; Xiaojun Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：September 6, 2007
• 年：2007
• 卷：111
• 期：35
• 页码：13256 - 13260
• 全文大小：108K
• 年卷期：v.111,no.35(September 6, 2007)
• ISSN：1932-7455

文摘

We report the observation of enhanced red emission at 613 nm originating from ⁵D₀ ⁷F₂ transition ofEu³⁺-doped CaMoO₄ with Bi³⁺ as an additive, under excitation either into the ⁵L₆ state with 395 nm or the⁵D₂ state with 465 nm. The luminescence properties as a function of Bi³⁺ and Eu³⁺ concentrations are studied.Strongly enhanced red emission of Eu³⁺ is obtained by adding Bi³⁺ instead of increasing the Eu³⁺ concentration.For a fixed Eu³⁺ concentration, there is an optimal Bi³⁺ concentration, at which the maximum luminescenceintensity is achieved. The red emission of CaMoO₄:0.05Eu³⁺ is enhanced by a factor of 3 as 0.2 Bi³⁺ isco-doped into the system, stronger than that of commercial Y₂O₂S:Eu³⁺ and Y₂O₃:Eu³⁺ phosphors. Lifetimeand diffuse reflection spectra measurements indicate that the red emission enhancement is due to the enhancedtransition probabilities from the ground state to ⁵L₆ and ⁵D₂ states of Eu³⁺ in the distorted crystal field inwhich it is considered that more odd-rank crystal field components are induced by crystal structural distortionand symmetry decreasing with the addition of Bi³⁺, leading to more opposite parity components, for example,4f⁵5d states, mixed into the 4f⁶ transitional levels of Eu³⁺. The energy transfer from Bi³⁺ to Eu³⁺ also occursand is discussed. The present material is a promising red-emitting phosphor for white light diodes with near-UV/blue GaN-based chips.