5 documents found, page 1 of 1
Piezoelectricity and crystal structure of H-beta-(2-Pyridy1)-Ala-OH amino acid ...
Wojtas, M.; Gagor, A.; Kholkin, A.Self-assembled peptide nanotubes (PNT) are unique nanoscale objects having a great potential for a multitude of applications. We report the congeneric studies on local piezoelectric properties of H-beta-(2-Pyridy1)-Ala-OH. It crystallizes in needle shaped microcrystals of the size from the fraction of micrometer up to tens of micrometers. The structure of this amino acid was determined by means of X-ray single ...
LOCAL PIEZOELECTRICITY IN SrTiO3-BiTiO3 CERAMICS
Grigalaitis, R.; Bagdzevicius, S.; Banys, J.; Tornau, E. E.; Bormanis, K.; Sternberg, A.; Bdikin, I.; Kholkin, A.Local piezoelectric properties of Bi-doped SrTiO3 ceramics have been investigated by piezoresponse force microscopy. The appearance of both out-of-plane and in-plane polarization components confirmed the piezoelectric nature of the obtained signal. The absence of labyrinth-like structures in observed piezoelectric contrast is not consistent with the expected existence of a relaxor ferroelectric state in this ma...
Optical Properties of Lead-Free NKN Films from Transmission and Spectral Ellips...
Schwarz, R.; Santos, L.; Ayouchi, R.; Bhattacharyya, S. R.; Mardolcar, U.; Leal, M.; Kholkin, A.Thin films of lead-free NaxK1-xNbO3 (NKN) were prepared by pulsed laser deposition (PLD) from ceramic targets of stoichiometric NKN or doped with 6% of lithium niobate (LN). At a deposition temperature of 600 degrees C a strong dependence of film morphology on laser fluence is revealed by SEM microscopy. Optical properties like band gap and index of refraction were obtained through transmission measurements and...
Layer-by-layer deposition of organically capped quantum dots
Neves, M.C.; Pereira, A.S.; Peres, M.; Kholkin, A.; Monteiro, T.; Trindade, T.Cadmium chalcogenide quantum dots (QD's) were synthesised using a single source approach while zinc oxide QD's were obtained by a colloidal technique. In both situations the dots were surface capped with tri-octylphosphine oxide (TOPO) hence leading to nanodispersed systems in organic solvents such as toluene. The organically capped QD's (CdSe, CdS and ZnO) were used as building-units to fabricate LbL (layer-by...
A green-emitting CdSe/poly(butyl acrylate) nanocomposite
Peres, M.; Costa, L. C.; Neves, A.; Soares, M. J.; Monteiro, T.; Esteves, A. C.; Barros-Timmons, A.; Trindade, T.; Kholkin, A.; Alves, E.CdSe/poly(butyl acrylate) nanocomposites were synthesized by in situ miniemulsion polymerization. The hybrid nanomaterial is very stable and presents a bright green photoluminescence at 2.29 eV under ultraviolet excitation. With the excitation conditions used the intensity of the emission band keeps nearly constant from 7 K to room temperature. The morphological, structural and room temperature electrical prope...