4:00pm - 4:30pmInvited
Non-equilibrium Nanostructures Driven by Light
University of Massachusetts Amherst, United States
Non-equilibrium processes are essential components of biology. However, examples of man-made non-equilibrium systems are few and far between. We have developed a light-driven assembly that induces mechanical turbulence in membranes, This process causes a relatively robust membrane to become permeable in the presence of light and only in the presence of light. The molecule feature that underlie this novel finding will be discussed.
4:30pm - 5:00pmInvited
Energy Conversion Processes based on Nanoparticles of Copper, Silver and Gold in Different Matrices
Humboldt University of Berlin, Germany
We report on the formation processes of noble metal nanoparticles (copper, silver and gold) in soda lime silicate matrices, on cellulose and in deep eutectic solvents. We describe the fundamental growth mechanisms, which significantly differ for these three metals. The growth mechanisms depend not only on the nature of the metal, but also on the fact that the stabilities of the respective oxides are remarkably different. As for copper, we find that copper is bound firmly to the glass matrix, while silver oxides are only stable up to a sharp borderline temperature (410 °C). Finally, gold oxides inside the glass matrix are not stable and cannot be formed. It has been shown explicitly by SAXS and ASAXS measurements under ex-situ and in-situ conditions that gold clusters are homogeneous. Indeed, the Guinier-plots as a function of X-Ray energies exhibit a constant slope irrespective of the applied energies. This means that gold nanoparticles are not inter-connected to the glassy network.
Understanding the fundamental formation mechanisms becomes straightforward as soon as the underlying individual processes (reduction, diffusion, nucleation, growth, Ostwald ripening and delayed Ostwald ripening can be separated and studied independently. This approach allows us to create and fabricate a great variety of weakly or heavily doped glasses with a broad range of novel applications. Selected examples are indicated here:
(1) Planck-white light emitters in silver doped glasses
(2) Emission color tuning by a novel energy transfer mechanism
(3) Conducting metal/metal-oxide composites
(4) Seebeck glasses for applications in energy converting devices
(5) IR-Up conversion glasses
(6) UV-Down-conversion devices
(7) SERS substrates with buried silver nanoparticles for long term stability
5:00pm - 5:30pmInvited
Resonant Photonic Structures for Biosensing and Energy Harvesting
Ben-Gurion University of the Negev, Israel
Resonant optical structures exhibit usually surface waves that can be useful for label free biosensing applications using their evanescent nature. When metals are involved in these structures then the local electromagnetic field is enhanced drastically near the surface which can then be used for surface enhanced spectroscopies and energy harvesting devices and systems.
During the last few years we have been working on developing different structural and system configurations for improving the performance of plasmonic and photonic biosensors based on improving the reading method and enhancing the local electromagnetic (EM) field further for the purpose of improving the sensitivity and lowering the detection limit based on SPR, SERS and SEF. The structural improvements include: (i) Planar thin metal films combined with dielectric films in the Kretschmann-Raether configuration, (ii) TIR dip sensor based on periodic dielectric stack, (iii) Periodic metallic structures on planar substrate, (iv) Nanosculptured thin films prepared by the glancing angle deposition technique, (v) Long range self-referenced plasmonic configurations, and lately, (vi) grating based structures, (vii) Combination of nanostructures with thin metal films for coupling of extended surface plasmons (ESP) to localized surface plasmons (LSP). The system improvements include: (i) diverging beam approach in the angular mode, (ii) polarimetric spectral mode, (iii) image and signal processing. Particularly we have shown recently that even much higher enhancement of the EM fields (1-3 orders of magnitude) is obtained by exciting the LSPs through extended surface plasmons (ESPs) generated at the metallic film surface using the Kretschmann-Raether and gratings configurations. The largest EM field enhancement and the highest SEF and SERS intensities are obtained when there is perfect matching between the conditions of exciting ESPs and LSPs.
5:30pm - 5:45pmOral
Enhancing the Infrared Absorption of Hybrid Organic–Inorganic Perovskites Using a High-Q Plasmonic Absorber Cavity
Nanyang Technological University, Singapore
We report on design, fabrication, and characterization of high-Q metamaterial at near infrared frequencies. The metal-dielectric-metal structure with top layer perforated with an array of overlapping annular and rectangular apertures support fundamental and higher order plasmonic resonances which result in high-Q response at mid-infrared frequencies. We then perform the surface enhance infrared spectroscopy of solution-processed hybrid organic–inorganic perovskites (HOIPs) with the formula CH3NH3PbI3 using high-Q metamaterial. We show that infrared absorption of extremely weak vibrational modes can be enhanced using well designed high-Q resonances to be seen with the naked eyes which are otherwise difficult to be seen.
5:45pm - 6:00pmOral
Unraveling the Photobehavior of a Salicylideneaniline Derivative Aggregates and Monomers within Silica-Based Materials
1Department of Physical Chemistry, Facultad de Ciencias Ambientales y Bioquimica y INAMOL, University of Castilla la Mancha (UCLM), Spain; 2Instituto de Química Orgánica, Consejo Superior de Investigaciones Científicas (CSIC), Spain
Nanoconfinement is one of the most interesting phenomena in physics, chemistry and biology. It leads to the observation of different spectroscopy and dynamics of the composites due the guest-guest and guest-host interactions. In this talk, we will report on the photobehavior of trapped (E)-(2-hydroxybenzyliden)- amino-4-nitrophenol (HBA-4NP) in zeolites faujasites (NaX and NaY) and mesoporous materials (R-MCM41 and SBA15) [1, 2]. In solution, HBA-4NP shows an ultrafast (< 80 fs) excited-state intramolecular proton transfer reaction with the keto (K) formation, whose lifetime is very short (14 ps) due to the rotational processes . Upon encapsulation, the K lifetime increases, being 6 ns for NaX/NaY complexes and 2 ns for R-MCM41/SBA15 ones, due to the confinement effect on the radiationless pathways [1, 2]. Furthermore, we observed H- and J-aggregates formation within these hosts, and the dependence of the their population on the nature of the host, and amount of Al atoms. The lifetimes of H- and J-aggregates (100 ps and 600 ps, respectively) are shorter than that of monomers due to excitonic coupling in the formers [1, 2]. Host-guest and guest-guest interactions play an important role in the ultrafast behavior of these composites, where the morphology (pore size) and chemical composition (doping metal) of the used materials give place to different photobehaviors, reflecting how nanoconfinement and material composition of the host affect to encapsulated dye photodynamics.
This work was supported by the MINECO and JCCM through projects: MAT2014-57646-P and PEII-2014-003-P.
 N. Alarcos, et al., J. Phys. Chem. C, 2014, 118 (15), 8217.
 N. Alarcos, et al., Micropor. Mesopor. Mater. 2016, 226, 34.
 N. Alarcos, et al. Chem. Phys. Lett., 2017, in press.
6:00pm - 6:15pmOral
Fabrication and Optical Characterization of ALD Deposited High Aspect Ratio Multidimensional Plasmonic Lattices
Technical University of Denmark, Denmark
In this work we report the fabrication and optical characterization of high aspect ratio, highly ordered one- and two-dimensional (1D/2D) lattices made from Al2O3, TiO2 and Al-doped ZnO (AZO). Specifically, AZO is an important and interesting material since it exhibits plasmonic behavior in near and mid-infrared range. The optical response can be tuned in a wide frequency range by adjusting the Al doping level and deposition conditions.
We fabricated samples by a combination of atomic layer deposition (ALD) and dry etch techniques. Initially, a silicone template was prepared using deep-UV photolithography and deep reactive ion etching (DRIE). The prepared silicon structures were passivated by ALD which is known to be an excellent technique for a deposition of inherently conformal coatings. A subsequent selective removal of the template leaves a negative replica which acts as a functional material.
The implemented technology has a huge potential as a highly flexible and versatile fabrication scheme for a large variety of materials and structural architecture. It allows fabricating a large (up to 2x2 cm2) coherent areas of nanostructures on a 150 mm wafers with future size down to 200 nm.
The prepared Al2O3 and TiO2 elements can be implemented in applications within photonic crystals, a new generation of Q-plates and sensors. The introduction of AZO components allows realization of structures which possess hyperbolic dispersion and near-epsilon-zero response.
Characterization results and optical performance will be reported at the conference.