Figure 2 . SEM images of the hybrid systems as labeled: a,b) deposited on Ag/Si(100) substrates; c-f) on a SiO 2 nanocolumnar fi lm; g,h) on PDMS. Color photograph in i) was taken for the hybrid system PtOEP/TiO 2 (meso) deposited on the fl exible PDMS substrate. This image is characterized by the intense red coloration of the PtOEP NWs.

The strong absorption of light [ 1 ] and the local amplifi cation of the electromagnetic fi eld [ 2 ] at the plasmon resonance of noble metal nanostructures have been the focus of hundreds of studies due to their practical applications for the fabrication of optical devices such as fi lters, non-linear optical components, or Raman enhancers. [ 3,4 ] The control of the plasmon features such as spectral width, [ 5 ] position, [ 6 ] and shape [ 7 ] can be accomplished by different physical deposition routes [8][9][10][11][12] providing adequate growing conditions of metal nanoparticles (MNPs). Pioneer works in the 1990s showed the optical selectivity of elongated Ag deposits on SiO 2 with applications as optical fi lters for windows to control solar heat gain and glare, among others. [ 13 ] Recently, assemblies of parallel stripes of MNPs have been fabricated onto preformed surfaces presenting a 1D periodic roughness [ 14 , 15 ] or bundled SiO 2 nanocolumns. [ 16 , 17 ] A signifi cant macroscopic optical dichroism has been reported for these systems that can be useful for the development of polarized light emitters or materials with an enhanced IR luminescence because of the excitation of two distinct plasmon resonances in the directions parallel (longitudinal mode) and perpendicular (transverse mode) to the stripes. [ 18 ] Architecture control of the metal assemblies plays a determinant role in the functional properties of the material. For this purpose, the softlithographic techniques provide means to accurately tailor the nanostructure of the materials. [18][19][20][21] Laser scanning is a softlithographic technique widely used to modify the shape and structure of metal nanoparticles. [21][22][23][24] Surface modifi cation can be easily achieved by in situ [ 21 ] or ex situ [22][23][24] pulsed laser treatment in the case of random systems of MNPs. In contrast, nothing has been reported about the effect of a pulsed laser on the structure and optical dichroism of autoorganized metal nanostructures. In this paper we show that nanosecond (ns) laser irradiation can be effectively used to control the optical dichroism of Ag stripes supported on SiO 2 nanocolumns (NCs). This dichroism can be effectively tailored along the full visible range. Thus, we propose the utilization of the AgNPs/SiO 2 NCs structures for writing dichroic patterns at the microscale with potential applications for encryption and data storage purposes.AgNPs/SiO 2 NCs fi lms were grown by a two-step process.[ 17 ]First, SiO 2 thin fi lms were deposited by glancing angle vapor deposition (GLAD) with a tilted columnar nanostructure and ≈ 350 nm thickness (see Figure S1a in the Supporting Information and the Experimental Section). [ 25 , 26 ] These structures present an anisotropic surface topography known as "bundling", [ 17 ] consisting of the coalescence of the NCs along the x -direction ( Figure S1b). The silver nanoparticles were then grown by DC sputtering at room temperature. The "bundled" SiO 2 NCs act as a template for the fabrication of Ag...

Ta 2 O 5 thin films with different nanostructure and surface roughness have been prepared by electron evaporation at different angles between the evaporation source and the substrates. Large variation of refraction indexes (n) from 1.40 to 1.80 were obtained by changing the geometry of evaporation and/or by annealing the evaporated films at increasing temperatures up to 1000°C to make them crystalline. Very flat and compact thin films (n ) 2.02) were also obtained by assisting the growth by bombardment with O 2 + ions of 800 eV kinetic energy. A similar correlation has been found between the wetting contact angle of water and the roughness of the films for the evaporated and evaporated + annealed samples, irrespective of their procedure of preparation and other microstructural characteristics. When the films were illuminated with UV light of h > E g ) 4.2 eV (E g , band gap energy of Ta 2 O 5 ), their surface became superhydrophilic (contact angle < 10°) in a way quite similar to those reported for illuminated TiO 2 thin films. The rate of transformation into the superhydrophilic state was smaller for the crystalline than for the amorphous films, suggesting that in Ta 2 O 5 the size of crystal domains at the surface is an important parameter for the control of this kinetics. Changes in the water contact angle on films illuminated with visible light were also found when they were subjected to implantation with N 2 + ions of 800 eV kinetic energy. The origin of this photoactivity is discussed in terms of the electronic band gap states associated with the nitrogen-implanted atoms. The possibility of preparing antireflective and self-cleaning coatings of Ta 2 O 5 is discussed.

The thin film configuration presents obvious practical advantages over the 1D implementation in energy harvesting systems such as easily manufacturing and processing and long lasting and stable devices.However, most of the ZnO-based piezoelectric nanogenerators (PENGs) reported so far relay in the exploitation of single-crystalline ZnO nanowires because their self-orientation in the c-axis and ability to accommodate long deformations resulting in a high piezoelectric performance. Herein, we show an innovative approach aiming to produce PENGs by combining polycrystalline ZnO layers fabricated at room temperature by plasma assisted deposition with supported small-molecule organic nanowires (ONWs) acting as 1D scaffold. The resulting hybrid nanostructure is formed by a single-crystalline organic nanowire conformally surrounded by a three dimensional (3D) ZnO shell that combines the mechanical properties of the organic core with the piezoelectric response of the ZnO layer. In a loop forward towards the integration of multiple functions within a single wire, we have also developed ONW@Au@ZnO nanowires including a gold shell acting as inner nanoscopic electrode. Thus, we have built and compare thin films and 3D core@shell ONW@ZnO and ONW@Au@ZnO PENGs showing output piezo-voltages up to 170 mV. The synergistic combination of functionalities in the ONW@Au@ZnO devices promotes an enhanced performance generating piezo-currents almost twenty times larger than the ONW@ZnO nanowires and superior to the thin film nanogenerators for equivalent and higher thicknesses.

Evidence is presented for infinite charge mobility in natural crystals of muscovite mica at room temperature. Muscovite has a basic layered structure containing a flat monatomic sheet of potassium sandwiched between mirror silicate layers. It is an excellent electrical insulator. Studies of defects in muscovite crystals indicated that positive charge could propagate over great distances along atomic chains in the potassium sheets in absence of an applied electric potential. The charge moved in association with anharmonic lattice excitations that moved at about sonic speed and created by nuclear recoil of the radioactive isotope 40 K. This was verified by measuring currents passing through crystals when irradiated with energetic alpha particles at room temperature. The charge propagated more than 1000 times the range of the alpha particles of average energy and 250 times the range of channelling particles of maximum energy. The range is limited only by size of the crystal.