UC/DC luminescence of Ho³⁺ doped pyrochlore structured Lab>2(1-b>b>x)b>Ybb>2xb>TiOb>5b> phosphor synthesized by sol-gel method

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• 作者：Junhua YOU ((尤俊华))^a ; Li MA ((马 理))^a ; Yingdong QU ((曲迎东))^a ; Rongde LI ((李荣德))^a ; Xuanwen LIU ((刘宣文))^b ; ^c ; Rui GUO ((郭 瑞))^b ; ^c ; ^{guorui791129@126.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：down/up-conversion ; Ho3+ ; La2TiO5 ; La2(1&ndash ; x)Yb2xTiO5 ; luminescence ; rare earths
• 刊名：Journal of Rare Earths
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：34
• 期：3
• 页码：235-239
• 全文大小：941 K

文摘

Ho³⁺ doped Lab>2(1–x)b>Ybb>2xb>TiOb>5b> samples were prepared by sol-gel method. Pyrochlore structured powders were obtained under the annealing of the as-prepared samples at 1100 °C for 3 h in the air. All the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescent spectroscopy. When x=0, we obtained Lab>2b>TiOb>5b> phosphors. Monitored at 546 nm, the excitation spectrum of Ho³⁺ activated Lab>2b>TiOb>5b> phosphors consisted of a broad band originating from the charge-transfer band (CTB) between Ho³⁺ ions and the nearest neighboring O^2– ions at 250–280 nm and four sharp bands associated to f-f transitions of Ho³⁺ ions at 350–500 nm. Under the blue light excitation at 461 nm, Ho³⁺ ion in Lab>2b>TiOb>5b> emitted an intense green emission band at 546 nm due to the transition of ⁵Sb>2b>, ⁵Fb>4b>→⁵Ib>8b>. Two intense bands were observed at 490 nm (blue, ⁵Fb>3b>→Ib>8b>) and 663 nm (red, ⁵Fb>5b>→⁵Ib>8b>) in the up-conversion (UC) spectrum under 980 nm NIR laser excitation in Lab>2b>TiOb>5b> phosphors activated with Ho³⁺ alone, whereas they were much different from the down-conversion (DC) luminescent samples. When x=7.5 mol.%–17.5 mol.%, the UC emission spectra of them dominated at 546 nm (green, ⁵Sb>2b>,⁵Fb>4b>→⁵Ib>8b>) and enhanced significantly with the dose of Yb³⁺ ion. The decay curve also confirmed that the transitions of ⁵Fb>4b>→⁵Ib>8b> and ⁵Sb>2b>→⁵Ib>8b> were merged into one emission band at 546 nm.