An Approach to Control of Band Gap Energy and Photoluminescence upon Band Gap Excitation in Pr3+-Doped Perovskites La1/3MO3 (M = Nb, Ta):Pr3+

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• 作者：Yoshiyuki Inaguma ; Tsunehiro Muronoi ; Keiko Sano ; Takeshi Tsuchiya ; Yuki Mori ; Tetsuhiro Katsumata ; Daisuke Mori
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：June 20, 2011
• 年：2011
• 卷：50
• 期：12
• 页码：5389-5395
• 全文大小：911K
• 年卷期：v.50,no.12(June 20, 2011)
• ISSN：1520-510X

文摘

We synthesized polycrystalline pristine and Pr³⁺-doped perovskites La_1/3MO₃ (M = Nb, Ta):Pr³⁺ and investigated their crystal structure, optical absorption, and luminescence properties. The optical band gap of La_1/3NbO₃ (3.2 eV) is smaller than that of La_1/3TaO₃ (3.9 eV), which is primarily due to the difference in electronegativity between Nb and Ta. In La_1/3NbO₃:Pr³⁺, the red emission assigned to the f鈥揻 transition of Pr³⁺ from the excited ¹D₂ level to the ground ³H₄ state upon band gap photoexcitation (near-UV) was observed, whereas the f鈥揻 transition of Pr³⁺ with blue-green emission from the excited ³P₀ level to the ground ³H₄ state was quenched. On the other hand, in La_1/3TaO₃:Pr³⁺, the blue-green emission upon band gap photoexcitation was observed. Their differences in emission behavior are attributed to the energy level of the ground and excited states of 4f² for Pr³⁺, relative to the energy levels of the conduction and valence bands, and the trapped electron state, which mediates the relaxation of electron from the conduction band to the excited state of Pr³⁺. La_1/3NbO₃:Pr³⁺ is a candidate red phosphor utilizing near-UV LED chips (e.g., 位 = 375 nm) as an excitation source.