Photoluminescence of nitrogen-doped anatase
Photoluminescence of nitrogen-doped anatase
复制标题
DOI：
10.1016/j.matchemphys.2008.04.053
复制
发表时间：
2008-10
影响因子：
4.6
通讯作者：
T. Okumura;Y. Kinoshita;Hiroaki Uchiyama;H. Imai
中科院分区：
文献类型：
--
作者：
T. Okumura;Y. Kinoshita;Hiroaki Uchiyama;H. Imai
使用由硫酸氧钛水合物和尿素的混合物煅烧制备的锐钛矿型TiO2，研究了光致发光随氮浓度的变化。通过改变混合物的摩尔比，TiO2 中氮的取代比 (x) 成功地从 0.004 变为 0.022。由于中间能隙态的形成而导致的 380-560nm 处的吸光度与制备条件控制的氮取代率成正比。相反，随着锐钛矿晶格的扩展，随着取代比的增加，源自带间跃迁的 382nm 处的荧光强度单调降低。另一方面，在 x=0.01 处观察到在 350nm 处激发的 560nm 光致发光的最大强度，这可能与从导带到中间能隙态的跃迁有关。发射的最佳取代比与可见光照射下亚甲基蓝和乙醛光催化分解的最佳取代比几乎一致。光致发光从根本上是由来自足够数量的中间带隙态的光激发与由于氮掺杂引起的晶格畸变或缺陷态而引起的受激电子和空穴的失活之间的平衡决定的。
Photoluminescence depending on nitrogen concentration was investigated using anatase-type TiO2prepared by the calcination of a mixture of titanyl sulfate hydrate and urea. The substitutional ratio (x) of nitrogen in TiO2was successfully varied from 0.004 to 0.022 by changing the molar ratio of the mixture. The absorbance at 380–560nm due to the formation of mid-gap states was proportional to the substitutional ratio of nitrogen controlled by the preparation conditions. In contrast, the fluorescent intensity at 382nm originating from the band-to-band transition monotonically decreased with an increase in the substitutional ratio with an expansion of the anatase lattice. On the other hand, the maximum intensity of photoluminescence at 560nm excited at 350nm, which could be associated with the transition from the conduction band to the mid-gap states, was observed at x=0.01. The optimal substitutional ratio for the emission was almost agreed with that for the photocatalytic decomposition of methylene blue and acetaldehyde under visible-light illumination. The photoluminescence was fundamentally determined by the balance between photoexcitation originating from a sufficient number of mid-gap states and deactivation of excited electrons and holes due to lattice distortion or defective states induced with the nitrogen doping.