High Efficiency Green Phosphor Ba9Lu2Si6O24:Tb3+: Visible Quantum Cutting via Cross-Relaxation Energy Transfers

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• 作者：Yongfu Liu ; Jianxin Zhang ; Changhua Zhang ; Jun Jiang ; Haochuan Jiang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 4, 2016
• 年：2016
• 卷：120
• 期：4
• 页码：2362-2370
• 全文大小：658K
• ISSN：1932-7455

文摘

Tb³⁺-doped phosphors are widely used in fluorescent lamps and plasma display panels (PDP) due to the strong vacuum ultraviolet (VUV)/UV light absorption of Tb³⁺. Most of these phosphors are fluorides. The quantum efficiency (QE) of these phosphors is more than 90%; however, it is still too low. Theoretically, one VUV/UV photon can convert two visible photons or more by visible quantum cutting (QC), and the QE can reach 200% or more. Usually, the oxides have a higher QE than fluorides. In this work, we obtained a novel oxide phosphor Ba₉Lu₂Si₆O₂₄:Tb³⁺ (BLS:Tb³⁺). Under the 251 nm UV-light excitation, QC processes occur in BLS:Tb³⁺ via cross-relaxation energy transfers (CRET) between Tb³⁺ ions, leading to intense green emissions around 552 nm. Based on an indirect method, the ideal QE is calculated nearly to be 171%. When the UV light absorption and energy losses are considered, the practical QE is near 144% estimated by a direct method. This value is much higher than that of the commercial phosphors of 90%, indicating the promising application of BLS:Tb³⁺ for fluorescent lamps and PDP. The CRET processes were investigated according to the luminescence spectra and decay curves.