Journal of Advances in Nanomaterials

6

Authors: Y. Y. Pan, Y. H. Su, C. H. Hsu, L. W. Huang, K. P. Dou, C. C. Kaun

Using first principles calculations, we investigate the geometric and electronic structures of organic–inorganic hybrid perovskite, FAPbX3 (FA = CH(NH2)2 +; X = Cl, Br, I). Since the organic molecule in the centre of the 3D hybrid perovskite is the key for its characteristics, here we compare FAPbX3 with MAPbX3 (MA = CH3NH3 +). The band gap of the former is smaller than the latter. Particularly, the calculated band gap of FAPbI3, 1.40 eV, is close to the experimental data, 1.41 eV. Furthermore, we analyze their orbitals, density of states and the spatial distribution of the charges, revealing that FAPbX3 can produce and transfer more excitons than MAPbX3 does.

10

Authors: Suleiman M. Elhamali, N.B. Ibrahim and S.Radiman

The combined substitution of Tb and Er ions at the yttrium site with a formula Y3-x-y Tbx Ery Fe5 O12, (x = 0.0, 0.2) and (y = 0.0, 0.2, 0.6, 1.0 and 1.4) were prepared by a sol-gel method. The crystalline structures of all films were found to have a pure single phase garnet structure. This result confirmed the successful incorporation of erbium and terbium ions into YIG structure. The lattice constant increased linearly with Er+3 concentrations from 12.379 to 12.532 Å. The morphology measurement revealed the formation of nanoparticles films. The magnetic properties characterization exhibited that all films are soft ferrimagnetic materials .The results showed the saturation magnetization Ms of pure YIG at 150 (emu / cm3 ). The Ms value decreased to 110 emu / cm3 at concentration of (x=0.2, y=0.0), then increased with increment of (y) content in a linear manner. The optical transparency of films was over 96 % at (y=0.6) in the wavelength range of 600 to 900 nm. At a short wavelength (λ < 400 nm), absorption coefficient α increased linearly with increment of Er3+ ions. Because of nearly zero absorption coefficient in the NIR region, the films could be useful as optical isolator.

12

Authors: Liping Duan, Xun Song, Huaiyu Sun, Siwei Yang and Fang Liao

. A sensitive fluorescent o-phenylenediamine-cysteine copolymer dots (O-Cys) detection system for Hg2+ was synthesized by a facile and one step hydrothermal method. As a sensitive fluorescent probe, the O-Cys showed excellent linear relationships with detection limit as low as 1.0×10-11 M with the concentrations of Hg2+ increasing from 2×10-11 M to 9×10-11 M . What's more, the O-Cys for the detection of Hg2+ was superior to most current methods and fluorescent material. At the same time, the working mechanism of O-Cys for Hg2+ detection was also explored. Hg2+ had higher fluorescent quenching ability for as-prepared O-Cys because Hg2+ was interation with amino group (– NH2) and thiol group (-SH) via a series of contrast test. And –SH enhanced the ability of Hg2+ detection to some extent. Therefore, this paper provided a good exponent of detection Hg2+ with low detection limit.