Seminarios y Eventos
Nuevas Arquitecturas en Química de Materiales
Coordinadora: Eva M. Garcia Frutos
04 de septiembre de 2017, 11:00 h. Sala de Seminarios, 182
Hybrid organic/inorganic devices based on nanomembranes
Carlos César Bof Bufon
Brazilian Nanotechnology National Laboratory (LNNano)
Nanomembranes (NMs) are freestanding nanostructures with mesoscopic thicknesses and lateral dimensions in the macroscopic range. By controlling the strain and stress engineering of thin-films, self-assembled three-dimensional (3D) structures, such as microtubes and micro-ribbons, based on NMs can be formed.  Since the patterning methods used for manufacturing the NMs are the same ones employed in standard microfabrication processes, the creation of 3D objects is a typical case where bottom-up and top-down methods are combined to give rise to novel technologies. In this seminar, the processes of synthesis, patterning and characterization of hybrid organic/inorganic NMs, will be presented considering three categories of devices: a) ultra-compact elements, such as supercapacitors, which use the mechanical flexibility of the NMs to reduce the devices footprint. [1,2] b) Sensors and biosensors that exploit the quasi-bidimensional nature of the NMs to improve their performance, and to incorporate different functionalities. [3,4] c) Hybrid organic/inorganic heterojunctions, that uses the mechanical flexibility of NMs, associated with their patterning and integration capabilities, to generate robust devices on-a-chip exhibiting novel physical and chemical properties. [5,6]
 Bufon, C.C.B.; Gonzalez, J.D.C.; Thurmer, D.J.; Grimm, D.; Bauer, M.; Schmidt, O.G, Nano Lett., 10, 2506-2510 (2010).
 Sharma, R.; Bufon, C.C.B.; Grimm, D.; Sommer, R.; Wollatz, A.; Schadewald, J.; Thurmer, D.J.; Siles, P.F.; Bauer, M.; Schimidt, O.G. Energy Mater., 4, 1301631 (2014).
 Vervacke, C.; Bufon, C.C.B.; Thurmer, J.D.; Schmidt, O.G.. RSC Adv., 4, 9723-9729 (2014).
 Grimm, D.; Bufon, C.C.B.; Deneke, C.; Atkinson, P.; Thurmer, D.J.; Schäffel, F.; Gorantla, S.; Bachmatiuk, A.;
24 de julio de 2017, 12:00 h. Sala de Seminarios, 182
Molecular Sieves: What are we doing and
what do we want to do?
Instituto de Química - UFRN (Brasil)
Molecular Sieves are solids with defined porosity and with the capacity of differentiate molecules through their dimensions and geometries. They can be used as catalysts for several kinds of reactions, and also for separation and adsorption process. In this Talk we describe what are we doing in LABPMEOL/BRAZIL in this subject and what are we planning to do. We discuss 5 challenges: 1) Ecofriendly synthesis of known structures, 2) Search for new structures – new SDAs. 3) Known structures with new compositions 4) New composite materials 5) Synthesize more accessible materials.
13 de marzo de 2017, 12:00 h. Sala de Seminarios, 182
Deposition of Nanoporous Silica Layer on Particle Surface
Vidyasirimedhi Institute of Science and Technology, Thailand
After the successful preparation of mesostructured and mesoporous silica films on solid supports by the solvent evaporation method,the preparation of mesoporous silica films have been extensively investigated partly due to the wide range of application of mesoporous silica films. The deposition of mesoporous silica layer on powders have also been reported extensively.
Here, we report the deposition of homogeneous nanoporous silica thin layer on a variety of solids surfaces especially micrometer size powders. The present reaction is very simple, where substrates (both plate and powder) were put into a homogeneous solution containing tetraethoxysilane, hexadecyltrimethylammonium chloride, methanol, water and ammonia. The present synthesis is a versatile method to prepare nanoporous silica thin layers on solid substrate especially when the reported procedure is not applicable; substrate with complex morphology and/or unstable in acidic solutions such as hydrotalcite and metal oxides. Mesoporous silica coating is regarded as a way to modify the surface property of powders as well as to impart new functions such as molecular sieving one on catalysts and adsorbents. Moreover, the surface modification of silica shell through grafting is possible to make the application of the core-shell particles more versatile.
02 de febrero de 2017, 12:00 h. Salón de Actos
Structural and Electronic Characteristics of Conjugated Materials: The key Role of DFT calculations
M. Carmen Ruiz Delgado
Department of Physical Chemistry, University of Málaga, Spain
The use of organic materials to design electronic devices constitute an ecological and suitable resource for our current "electronic world". Actually these materials have been implemented into electronic devices, like organic light-emitting diodes (OLEDs), organic solar cells (OSCs), and organic field-effect transistors (OFETs). These materials provide several advantages (low cost, light weight, good flexibility and solubility to be easily printed) that cannot be afforded with silicium. They can also potentially interact with biological systems, something impossible with inorganic devices. Between these materials we can include small molecules, polymers, fullerenes, nanotubes, graphene, other carbon-based molecular structures and hybrid materials.
Here we analyze the electronic and molecular characteristics of different π-conjugated structures. Specifically, we focus on the study of materials ranging from small oligomers to polymers and carbon nanostructures, with different backbone configurations: (i) donor-acceptor configuration, (ii) 1D lineal or 2D branched conjugated backbones, and (iii) encapsulated systems, among others. The key role of DFT calculations for an accurate interpretation of the experimental results is highlighted, showing their potential in helping guide the design of new materials for organic electronics.