Photocatalytic degradation of methyl orange by nano-TiO_2 thin films prepared by RF magnetron sputtering

Nano-TiO2 thin films are deposited by radio frequency （RF） magnetron sputtering using TiO2 ceramic target and characterized by X-ray diffractometer, atomic force microscope, and ultraviolet-visible spectrophotometer. The photocatalytic activity is evaluated by light-induced degradation of methyl orange solutions （5, 10, and 20 ppm） using a high pressure mercury lamp as the light source. The film is amorphous, and its energy gap is 3.02 eV. The photocatalytic degradation of methyl orange solution is the first-order reaction and the apparent reaction rate constants are 0.00369, 0.0024, and 0.00151 for the methyl orange solution concentrations of 5, 10, and 20 ppm, respectively.     

K_4Ce_2Ta_(10-x)Nb_xO_(30)-WO_3复合物的光催化储能特性

为获得可见光响应的储能光催化材料,以离子交换法获得的钨酸溶液与可见光响应光催化剂K4Ce2Ta10-xNbxO30(x=0,5,10)为原料,制备了K4Ce2Ta10-xNbxO30-WO3(x=0,5,10)复合光催化剂。采用XRD,TEM,BET,UV-V is等方法表征了材料的物理化学特性,通过电化学方法和抗菌实验对其储能特性进行表征,分析和研究了K4Ce2Ta10-xNbxO30能带结构对其光催化储能效应的影响及作用机制。研究结果表明,稀土元素Ce贡献于K4Ce2Ta10-xNbxO30能带结构的调变,使得K4Ce2Ta10-xNbxO30-WO3复合光催化材料具有可见光储能特性,在黑暗中也显示出一定的储能抗菌效应。该材料的储能性能受Nb含量和K4Ce2Ta10-xNbxO30的导带位置的影响:随着Nb含量的增加,光生电子还原能力下降,导致储能性能降低。     

Fast-speed self-powered PEDOT: PSS/α-Ga2O3 nanorod array/FTO photodetector with solar-blind UV/visible dual-band photodetection

The $\alpha $-Ga$_{2}$O$_{3}$ nanorod array is grown on FTO by hydrothermal and annealing processes. And a self-powered PEDOT:PSS/$\alpha $-Ga$_{2}$O$_{3}$ nanorod array/FTO (PGF) photodetector has been demonstrated by spin coating PEDOT:PSS on the $\alpha $-Ga$_{2}$O$_{3}$ nanorod array. Successfully, the PGF photodetector shows solar-blind UV/visible dual-band photodetection. Our device possesses comparable solar-blind UV responsivity (0.18 mA/W at 235 nm) and much faster response speed (0.102 s) than most of the reported self-powered $\alpha $-Ga$_{2}$O$_{3}$ nanorod array solar-blind UV photodetectors. And it presents the featured and distinguished visible band photoresponse with a response speed of 0.136 s at 540 nm. The response time is also much faster than the other non-self-powered $\beta $-Ga$_{2}$O$_{3 }$ DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by the built-in electric field in the depletion regions of PEDOT:PSS/$\alpha $-Ga$_{2}$O$_{3}$ heterojunction. The results herein may prove a promising way to realize fast-speed self-powered $\alpha $-Ga$_{2}$O$_{3}$ photodetectors with solar-blind UV/visible dual-band photodetection by simple processes for the applications of multiple-target tracking, imaging, machine vision and communication.     

Optical nonlinear characteristics of MgF_2 films containing Cu nanoparticles

An investigation is made on the optical nonlinear characteristics of MgF2 fihns containing Cu nanoparticles. When the Cu volume fraction is 0.1, at approximately εm ＋ 2εd = 0, the film exhibits a strong thirdorder optical nonlinear refractive coefficient of 1.0×10^-9 cm2/W, a nonlinear refractive index of about -4.0×10^-7 esu, a third-order optical nonlinear response of about 6.8×10^-8s esu, and a figure of merit of about 1.0×10^-11. The result shows that the film may have potential applications in optoelectronic technology.