Photoluminescence of perovskite nanosheets prepared by exfoliation of layered oxides, K2Ln2Ti3O10, KLnNb2O7, and RbLnTa2O7 (Ln:lanthanide ion)
Photoluminescence of perovskite nanosheets prepared by exfoliation of layered oxides, K2Ln2Ti3O10, KLnNb2O7, and RbLnTa2O7 (Ln:lanthanide ion)
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DOI：
10.1021/ja7114772
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发表时间：
2008-06-04
影响因子：
15
通讯作者：
Matsumoto, Yasumichi
中科院分区：
文献类型：
--
作者：
Ida, Shintaro;Ogata, Chikako;Matsumoto, Yasumichi
通过剥离单层或双层钙钛矿氧化物K（2）Ln（2）Ti（3）O（10）、KLnNb（2）O（7）和RbLnTa（2）O（7）（Ln：镧系离子）制备发光钙钛矿纳米片。各个纳米片的厚度对应于母体层状化合物中的钙钛矿块的厚度。强烈的红色和绿色发射观察到在水溶液中的Gd 1.4Eu 0.6Ti 3 O 10-和La 0.7Tb 0.3Ta 2 O 7-纳米片，分别在紫外光照射下，能量大于相应的主机氧化物带隙。激发光谱和带隙吸收的重合表明可见光发射是由纳米片内的能量转移引起的。Gd_（1.4）Eu_（0.6）Ti_3 O_（10）-纳米片的红光发射强度远强于先前报道的La_（0.90）Eu_（0.05）Nb_2 O_（7）-纳米片。通过施加磁场（1.3-1.4 T）可以调制Gd1.4Eu0.6Ti3O10-和La0.7Tb0.3Ta2O7-纳米片的发射强度，这引起纳米片在溶液中取向的变化。当激发光和磁场方向相互垂直时，发射强度增加，当激发光和磁场共线且相互垂直于发射光的检测方向时，发射强度减小。
Luminescent perovskite nanosheets were prepared by exfoliation of single- or double- layered perovskite oxides, K(2)Ln(2)Ti(3)O(10), KLnNb(2)O(7), and RbLnTa(2)O(7) (Ln: lanthanide ion). The thickness of the individual nanosheets corresponded to those of the perovskite block in the parent layered compounds. Intense red and green emissions were observed in aqueous solutions with Gd1.4EU0.6Ti3O10- and La0.7Tb0.3Ta2O7-nanosheets, respectively, under UV illumination with energies greater than the corresponding host oxide band gap. The coincidence of the excitation spectrum and the band gap absorbance indicates that the visible emission results from energy transfer within the nanosheet. The red emission intensity of the Gd1.4Eu0.6Ti3O10-nanosheets was much stronger than that of the La0.90Eu0.05Nb2O7-nanosheets reported previously, The strong emission intensity is a result of a two-step energy transfer cascade within the nanosheet from the Ti-O network to Gd3+ and then to Eu3+. The emission intensities of the Gd1.4Eu0.6Ti3O10- and La0.7Tb0.3Ta2O7-nanosheets can be modulated by applying a magnetic field (1.3-1.4 T), which brings about a change in orientation of the nanosheets in solution. The emission intensities increased when the excitation light and the magnetic field directions were perpendicular to each other, and they decreased when the excitation and magnetic field were collinear and mutually perpendicular to the direction of detection of the emitted light.