Phase structure and luminescence properties of Eu3+-doped TiO2 nanocrystals synthesized by Ar/O2 radio frequency thermal plasma oxidation of liquid precursor mists.
Phase structure and luminescence properties of Eu3+-doped TiO2 nanocrystals synthesized by Ar/O2 radio frequency thermal plasma oxidation of liquid precursor mists.
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DOI：
10.1021/jp053329l
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发表时间：
2006-01
期刊：
影响因子：
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通讯作者：
Ji-guang Li;Xiaohui Wang;Kenji Watanabe;T. Ishigaki
中科院分区：
文献类型：
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作者：
Ji-guang Li;Xiaohui Wang;Kenji Watanabe;T. Ishigaki
本工作通过 Ar/O2 热等离子体氧化含有四正丁醇钛和硝酸铕(III)的液体前驱体雾，在等离子体鞘层中输入不同的 O2 (10-90 L/min)，并在前驱体溶液中添加 Eu3+ (Eu/(Ti + Eu) = 0-5 原子%)。所得纳米粉末是研究范围内的锐钛矿 (30-36 nm) 和金红石 (64-83 nm) 多晶型物的混合物，但如 X 射线衍射 (XRD) 和拉曼光谱所示，金红石分数随着 Eu3+ 添加量的增加而稳定增加，因为通过置换在 TiO2 气体簇中产生了氧空位。 Eu3+掺杂。可以掺杂到 TiO2 晶格中的 Eu3+ 的量限制为最多 0.5 原子％，高于此值，最终产品中会形成 Eu2Ti2O7 烧绿石。高分辨率透射电子显微镜（HRTEM）观察表明颗粒致密，尺寸范围从几纳米到180纳米。通过激发、UV-vis（紫外-可见）和 PL（光致发光）光谱的综合研究证实了从 TiO2 主体到 Eu3+ 离子的有效非辐射能量转移，这在当前系统的湿化学衍生纳米粒子或薄膜中很少报道。因此，通过用短于 405 nm 的紫外光激发 TiO2 主体，或通过在超出 TiO2 吸收限（405 nm）的波长直接激发 Eu3+，可以从等离子体生成的纳米粉末中观察到亮红色发射。
Eu3+-doped TiO2 luminescent nanocrystals have been synthesized in this work via Ar/O2 thermal plasma oxidizing mists of liquid precursors containing titanium tetra-n-butoxide and europium(III) nitrate, with varied O2 input in the plasma sheath (10-90 L/min) and Eu3+ addition in the precursor solution (Eu/(Ti + Eu) = 0-5 atom%). The resultant nanopowders are mixtures of the anatase (30-36 nm) and rutile (64-83 nm) polymorphs in the studied range, but the rutile fraction increases steadily at a higher Eu3+ addition, as revealed by X-ray diffraction (XRD) and Raman spectroscopy, because of the creation of oxygen vacancies in the TiO2 gas clusters by substitutional Eu3+ doping. The amount of Eu3+ that can be doped into a TiO2 lattice was limited up to 0.5 atom%, above which Eu2Ti2O7 pyrochlore was formed in the final products. High resolution transmission electron microscopy (HRTEM) observation indicates that the particles are dense and have sizes ranging from several nanometers up to 180 nm. Efficient nonradiative energy transfer from the TiO2 host to Eu3+ ions, which was seldom reported in the wet-chemically derived nanoparticles or thin films of the current system, was confirmed by combined studies of excitation, UV-vis (ultraviolet-visible), and PL (photoluminescence) spectroscopy. As a consequence of this, bright red emissions were observed from the plasma-generated nanopowders either by exciting the TiO2 host with UV light shorter than 405 nm or by directly exciting Eu3+ at a wavelength beyond the absorption edge (405 nm) of TiO2.