The synthesis of nanosized powders and their assembly is of considerable importance to the microelectronics industry because of the pervasive drive to miniaturize components. In this work, silver (Ag) nanoparticls was syntheized. Polygonal silver nanoparticls were synthesized by reacting AgNO3 with hydroquinone, in the presence of poly-(vinylpyrrolidone) (PVP) and an ionic liquid 1-n-butyl-3-methylimidazolium hexafluoroborate ([BMIM]·PF6) at ambient temperature. XRD shows that the crystal structure of the nanoparticles is face-centered cubic. TEM measurements display the silver particles with uniform size and narrow particle size distributions. The UV-Vis spectra of the nanoplates distinguish from those of the samples prepared in the absence of PVP and/or ILs. This method is facile and the as-prepared silver nanoparticls are also stable in some solvents, such as ethanol and water.
Wu Yongzhong Zhao Xiaolu Tian Fang Hao Xiaopeng Yang Jiaxiang
The electronic properties of ground state and charged excited states of nondegenerate polydiacetylene were investigated by means of a tight-binding model. The parameters of the model were obtained by comparison of the experimental and other theoretical results. It was found that there is a stable dimerized structure of polydiacetylene in ground state and the doping induces the nonlinear excitations, such as polarons and bipolarons. In order to compare the stability of polaron and bipolaron, the creation energy and binding energy were separately defined. By neglecting the electron-electron Coulomb interaction, a bipolaron is more stable than two independent polarons.
LI Yuan1, HU Guichao1, XIA Caijuan1, LIU Desheng1,2 & XIE Shijie1,2 1. School of Physics and Microelectronics, Shandong University, Jinan 250100, China
YbAl3(BO3)4 crystal of good optical quality was grown by the flux method. The structure of YbAl3(BO3)4 crystal was determined by single-crystal X-ray diffraction. The experiment shows that YbAl3(BO3)4 belongs to the double bo-rates with a trigonal structure. The space group is R32 and its unit cell constants were measured to be a = 0.92965 nm, c=0.72129 nm, V = 0.53673 nm3, Z=3. The transmittance spectra were measured. The cut-off of YbAl3(BO3)4 crystal is 216 nm, and there are two absorption peaks located at 940 and 975 nm from 190 nm to 2600 nm. The thermal properties of YbAl3(BO3)4 crystal were studied for the first time. The average thermal expansion coefficients were determined to be 2×10-6/℃, 9.5×10-6/℃along a- and c- direction. The specific heat of YbAl3(BO3)4 crystal was measured to be 0.6695 J·(g·℃) -1 at room temperature . All results indicate that the YbAl3(BO3)4 crystal is an excellent stoichioimet-ric laser material.
Single crystal of cobalt (Co)-doped Y3Sc2Ga3O12 (YSGG) with the dimensions up to Φ20×40 mm3 and undoped YSGG crystal with the dimensions up to Φ28×60 mm3 have been grown using the Czochralski technique. The structure of the crystal was characterized by the X-ray powder diffraction (XRPD) method. The absorbance spectra of the crystal shows that it has strong absorption bands at 606 and 1540 nm. The results indicate that the crystal Y3Sc2Ga3O12 may be a kind of good Q-switch material.
