偶氮侧基聚合物光致异构动力学研究

本文对偶氮侧基聚合物相位共轭光时间特性进行了研究,得到了相位共扼光产生机制─光致异构过程的时间常数.在相位共轭光上升阶段,其时间常数在0.4～0.5s之间,在相让共轭光的衰减过程,衰减满足双指数关系,分段拟合得到较好的结果,且得到快过程的时间常数为0.27s,慢过程的时间常数为0.78s.     

Optical Performance of N-Face A1GaN Ultraviolet Light Emitting Diodes

The optical property and injection efficiency of N-face A1GaN based ultraviolet light emitting diodes （UV-LEDs） are studied and compared with Ga-face A1GaN based UV-LEDs. A staircase electron injector is introduced in the N-face AIGaN based UV-LED. The electroluminescence spectra, power-current performance curves, energy band diagrams, carrier concentration and radiative recombination rate are numerically calculated. The results indicate that the N-face UV-LED has a better optical performance than the Ga-face UV-LED, and the injection efficiency is enhanced owing to the fact that the staircase electron injector is available for UV-LEDs.     

激光法制备纳米a-SixNy:H的光谱及键结构研究

用红外吸收光谱和喇曼光谱对激光法制备的纳米a-Si_xN_y:H粉末及其加压成形块体的键结构进行研究,发现在a-Si_xN_y:H中存在着Si-N,Si-Si,Si-H,N-H,Si-O-Si及OH基团,讨论了块体及其退火后光谱畸变和键结构变化。 关键词：     

AZOBENZENE POLYMER FILMS FOR OPTICAL STORAGE AND HIGH-ORDER DIFFRACTION (I)——POLY[4'-BIS(N,N-OXYETHYLENE) IMINO-4-NITROAZOBENZENE SUCCINYL] FILM

The properties of phase conjugated (PC) beam and stable optical storage in an azobenzene polymer film were studied by degenerate four-wave mixing. With low-intensity incident waves (peak value of the pulses of the order of W/cm²), the PC beam as well ms diffraction beams were observed and then disappeared after turning off one of the three incident Beams. When the peak intensities of the incidenl beams reached the order of 10 W/cm², the PC beam did not disappear but decreased to some extent after turning off the writing beams. As the peak intensities of incident beams increased to the order of l0³ W/cm², diffraction up to 4th-order was observed. When all of the three incident waves were turned on, three groups of high-order forward and backward diffraction heams were observed. Turning off two of the three incident beams, the diffraction beams of the other incident beams did not decrease obviously, i.e., stable optical storage was realized. After the experiments, brilliant hologram spot was observed and could be maintained over 120 days without obvious change.     

Energy transfer ultraviolet photodetector with 8-hydroxyquinoline derivative-metal complexes as acceptors

We choose 8-hydroxyquinoline derivative-metal complexes(Beq,Mgq,and Znq) as the acceptors(A) and 4,4',4"-tri-(2-methylphenyl phenylamino) triphenylaine(m-MTDATA) as the donor(D) respectively to study the existing energy transfer process in the organic ultraviolet(UV) photodetector(PD),which has an important influence on the sensitivity of PDs.The energy transfer process from D to A without exciplex formation is discussed,differing from the working mechanism of previous PDs with Gaq[Zisheng Su,Wenlian Li,Bei Chu,Tianle Li,Jianzhuo Zhu,Guang Zhang,Fei Yan,Xiao Li,Yiren Chen and Chun-Sing Lee 2008 Appl.Phys.Lett.93 103309)]and REq[J.B.Wang,W.L.Li,B.Chu,L.L.Chen,G.Zhang,Z.S.Su,Y.R.Chen,D.F.Yang,J.Z.Zhu,S.H.Wu,F.Yan,H.H.Liu,C.S.Lee 2010 Org.Electron.111301]used as an A material.Under 365-nm UV irradiation with an intensity of 1.2 mW/cm~2,the m-MTDATA:Beq blend device with a weight ratio of 1:1 shows a response of 192 mAAV with a detectivity of 6.5 × 10~(11) Jones,which exceeds those of PDs based on Mgq(146 mA/W) and Znq(182 mA/W) due to better energy level alignment between m-MTDATA/Beq and lower radiative decay.More photophysics processes of the PDs involved are discussed in detail.     

AZOBENZENE POLYMER FILMS FOR OPTICAL STORAGE AND HIGH-ORDER DIFFRACTION (I)——POLY[4''-BIS(N, N-OXYETHYLENE) IMINO-4-NITROAZOBENZENE SUCCINYL] FILM

The properties of phase conjugated (PC) beam and stable optical storage in an azobenzene polymer film were studied by degenerate four-wave mixing. With low-intensity incident waves (peak value of the pulses of the order of W/cm²), the PC beam as well ms diffraction beams were observed and then disappeared after turning off one of the three incident Beams. When the peak intensities of the incidenl beams reached the order of 10 W/cm², the PC beam did not disappear but decreased to some extent after turning off the writing beams. As the peak intensities of incident beams increased to the order of l0³ W/cm², diffraction up to 4th-order was observed. When all of the three incident waves were turned on, three groups of high-order forward and backward diffraction heams were observed. Turning off two of the three incident beams, the diffraction beams of the other incident beams did not decrease obviously, i.e., stable optical storage was realized. After the experiments, brilliant hologram spot was observed and could be maintained over 120 days without obvious change.     

偶氮苯液晶薄膜相位共轭的光学记录研究

利用间并四波混频研究了一种偶氮苯液昌聚合物的相位共轭和光学记录特性，在近共振条件下，用低功率Ｎｄ：ＹＡＧ倍频激光得到高效率的相位共轭光和高阶衍射光，当光强达到１０Ｗ／ｃｍ＾２量级时，薄膜显示出光记录效应，即在撒掉写入光之后，相位共轭波并不消失，进一步大光强到１０＾３Ｗ／ｃｍ＾２量级时，出现三组分别只与前向泵浦光，后向泵浦光和信号有关的高阶衍射光。其中观察到第三阶衍射光，且在撒掉任两束光后，所剩一束     

OPTICAL STORAGE MECHANISM AND HIGH-ORDER DIFFRACTION PROPERTIES OF NITROAZOBENZENE-CONTAINING POLYESTER FILMS

Using Nd:YAG second harmonic pulse (100 ps), the optical storage proper-ties of two novel polyesters, poly [4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene suc-cinyl] and poly [2'-chloro-4'-bis (N, N-oxyethylene) iminth-4-nitroazobenzene succiny] havebeen studied by multiwave mixing. The high-order diffractions of the orientation gratingsinduced by anisotropy via the reorientation of nitroazobenzene groups and optical infor-mation storage with long-term stability have been realized by multiwave mixing in theirfilms. Up to 3rd order forward diffraction was detected in two wave mixing, while up to 4thorder backward diffraction was observed in degenerated four wave mixing. The recordingmechanism was explained by the trans-cis-trans isomerization cycles of azobenzene groups.The isomerization of these azobenzene groups probably undergoes with inversion mecha-nism under the experimental conditions. The information recorded in these films has beenkept for more than 6 months.     

高调谐BST薄膜制备及介电性能研究

用改进的溶胶凝胶(sol-gel)法逐层制备钛酸锶钡(Ba_0.6Sr_0.4TiO₃, BST)薄膜,研究中间热处理(preheating,PT)对薄膜结构及介电性能的影响.X射线衍射(XRD)表明,BST薄膜主要沿(110)方向生长,对应立方钙钛矿结构,PT使晶化增强.X射线光电子能谱(XPS)表明,PT促使表面非钙钛矿结构向钙钛矿结构转变.原子力显微镜(AFM)和介电性能测试表明,随着PT频次的增加,薄膜形貌改善,表面粗糙度降低,介电调谐 关键词： 中间热处理 高调谐 溶胶凝胶法 钛酸锶钡