Biao Zheng(郑标,硕士生), Senyuan Xu(徐森元,硕士生), Lin Lin(林林), Zhezhe Wang(王哲哲), Zhuohong Feng(冯卓宏) and Zhiqiang Zheng(郑志强)*, Plasmon enhanced near-infrared quantum cutting of KYF4: Tb3+, Yb3+ doped with Ag nanoparticles, Optics Letters 40(11), 2630-2633 (2015).
A novel quantum cutting (QC) phosphor KYF4:Tb3+, Yb3+ doped Ag nanoparticles (NPs) was prepared by using the sol-gel method. Plasmon enhanced near-infrared (NIR) QC involving Yb3+ ion at 975nm (2F5/2→2F7/2) emission was achieved under the excitation of 374nm (7F6→5D3) and 485nm (7F6→5D4) of Tb3+ ions, respectively. The effect of Ag NPs on NIR QC luminescence was investigated, and the results show that QC luminescence intensity first increases, then decreases with the increase of the Ag NPs concentration. The maximum enhancement factor is about 1.9 when the concentration of Ag NPs is 0.5%. Our study may have potential application in the field of silicon-based solar cells.
Zhezhe Wang(王哲哲), Zhuohong Feng(冯卓宏), Lin Lin(林林), Pingping Huang(黄萍萍,硕士生), Zhiqiang Zheng(郑志强)*,Top-down patterning and self-assembly of flower-like gold arrays forsurface enhanced Raman spectroscopy, Applied Surface Science 356, 1314-1319 (2015).
A low-cost and controllable fabrication method of flower-like Au arrays has been developed by usingphotosensitive sol–gel and electrochemical reaction self-assembly strategy on a TiO2 patterned Si sub-strate. The effects of concentration of HAuCl4solution and applied voltage have been investigated totailor the growth of Au nanoflowers. At a proper applied voltage (12 V) and concentration (0.005 mM),fractal flower-like Au arrays is prepared and shows strong SERS effect. The concentration of detectableRhodamine 6G can be down to 10?10M using the short data integration time (5 s). These flower-like Auarrays with strong SERS effect could be used in biosensors and nanodevices with molecule-level detection.
Lin Lin(林林), Hui Lin(林慧,硕士生), Zhezhe Wang(王哲哲), Jixing Chen(谌基兴,硕士生), Ruijie Huang(黄瑞杰,本科生), Xin Rao(饶鑫,本科生), Zhuohong Feng(冯卓宏) and Zhiqiang Zheng(郑志强)*, Quantum-cutting of KYF4:Tb3+,Yb3+ under multiple excitations with high Tb3+ concentration, Optical Materials 36(6), 1065-1069 (2014).
A new kind of quantum-cutting (QC) phosphor KYF4:Tb3+,Yb3+ was prepared by the sol–gel method by using trifluoroacetic acid as a fluorine source. Tb3+-doped samples represent high quenching concentration as 15%. The near-infrared fluorescence spectra of Tb3+&Yb3+ co-doped samples with high Tb3+ concentration (15%) indicate that QC can occur under different excitations of Tb3+, and the 7F6 → 5D3 excitation (～374 nm) is more effective than 7F6 → 5D4 excitation (～483 nm). Through the lifetime measurement, the maximum of QC efficiency (ηQE) under 7F6 → 5D4 and 7F6 → 5D3 excitations are calculated as 161% and 150%, respectively. The results all above infer that this phosphor can make use of high-energy photons of several wavelengths and may raise the conversion efficiency of solar cells greatly.
Xiaoyan Li(李小燕), Yunlong Yu(余运龙), Zhiqiang Zheng(郑志强)* , A temperature dependent investigation of upconversion emission in Er3+:PLZT transparent ceramic,Online
The upconversion emission of Er3+:PLZT transparent ceramic was investigated at different temperatures from 10 to 300 K. Emission bands around 540, 564 and 682 nm corresponding to transitions from 2H11/2, 4S3/2, and 4F9/2 to 4I15/2 were observed. As the measurement temperature was increased, the intensities of the 564 and 682 nm peaks decreased, while that of the 540 nm peak increased. Based on the rate equation theory, a model for the dynamics of upconversion emission in Er3+:PLZT ceramic was proposed. Impressively, the calculations agree well with the experimental data in the whole temperature range. Additionally, the temperature dependent upconversion emission behavior in Er3+:PLZT ceramic was discussed in terms of the Boltzmann thermal distribution and nonradiative relaxation.