Junmei Fan

Formation of cubic Cu mesocrystals by a solvothermal reaction

Cubic Cu mesocrystals were prepared via a facile solvothermal reaction in a mixed solvent of glycerol–water. The microstructure of synthesized mesocrystals can be successfully controlled by adjusting the volume ratio of glycerol/water. The evolution of these cubic Cu mesocrystals was investigated and the mechanism was discussed. The oriented attachment process controls the initial stage in the formation of scabbled cubic Cu mesocrystals and then Ostwald ripening process contributes to the formation of the final Cu mesocrystals by shearing the scabbled mesocrystals. The influences of reaction temperature and NaOH concentration on the morphology of the synthesized mesocrystals were also investigated. Isotropic conductive adhesives (ICA), filled with cubic Cu mesocrystals, exhibit a low bulk resistivity, of about 5.21 × 10−4 Ω cm.

Growth and characterization of new laser crystal Nd3+:Ca2.85Gd0.1(VO4)2

The crystal growth, crystal defect, thermal properties and luminescence properties of Nd3+:Ca2.85Gd0.1(VO4)(2) were investigated. Nd3+:Ca2.85Gd0.1(VO4)(2) crystal grown by Czochraski method was green colored, and was not transparent, which was possibly due to residual impurities in V2O5, or due to the lack of oxygen in the growth process. And the Nd3+:Ca2.85Gd0.1(VO4)(2) crystal had the existence of 180 degrees domains. However, the annealing method could effectively decrease the crystal defect and greatly improve the quality of crystal. The average thermal expansion coefficients calculated were alpha(perpendicular to c)=9.5767x10(-6) K-1, alpha(parallel to c)=10.7647x10(-6) K-1, respectively. The specific heat of Ca2.85Gd0.1(VO4)(2) was 0.401 J/(g.K) at 330 K. The polarized absorption spectra and the polarized fluorescence spectra of Ca2.85Gd0.1(VO4)(2) were measured at 330 K. Based on the Judd-Ofelt theory, the intensity parameter Omega(lambda) (lambda = 2, 4, and 6), the radiation transition probabilities tau(rad), the stimulated-emission cross section sigma(p) in Nd3+:Ca2.85Gd0.1(VO4)(2) crystal were calculated.