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Dive into the research topics where Nikolaos T. Panagiotopoulos is active.

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Featured researches published by Nikolaos T. Panagiotopoulos.


ACS Nano | 2012

Nanocomposite catalysts producing durable, super-black carbon nanotube systems: Applications in solar thermal harvesting

Nikolaos T. Panagiotopoulos; Evmorfia K. Diamanti; Loukas E. Koutsokeras; Maria Baikousi; E. Z. Kordatos; Theodore E. Matikas; Dimitrios Gournis; P. Patsalas

A novel two-step approach for preparing carbon nanotube (CNT) systems, exhibiting an extraordinary combination of functional properties, is presented. It is based upon nanocomposite films consisting of metal (Me = Ni, Fe, Mo, Sn) nanoparticles embedded into diamond-like carbon (DLC). The main concept behind this approach is that DLC inhibits the growth of Me, resulting in the formation of small nanospheres instead of layers or extended grains. In the second step, DLC:Me substrates were used as catalyst templates for the growth of CNTs by the thermal chemical vapor deposition (T-CVD) process. X-ray photoelectron spectroscopy (XPS) has shown that at the T-CVD temperature of 700 °C DLC is completely graphitized and NiC is formed, making DLC:Ni a very effective catalyst for CNT growth. The catalyst layers and the CNT systems have been characterized with a wide range of analytical techniques such as Auger electron spectroscopy and X-ray photoelectron spectroscopy (AES/XPS), X-ray diffraction, reflectivity and scattering, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and optical and electrical testing. The produced CNTs are of excellent quality, without needing any further purification, durable, firmly attached to the substrate, and of varying morphology depending on the density of catalyst nanoparticles. The produced CNTs exhibit exceptional properties, such as super-hydrophobic surfaces (contact angle up to 165°) and exceptionally low optical reflection (reflectivity <10(-4)) in the entirety of the visible range. The combination of the functional properties makes these CNT systems promising candidates for solar thermal harvesting, as it is demonstrated by solar simulation experiments.


Nanotechnology | 2015

Self-assembled plasmonic templates produced by microwave annealing: applications to surface-enhanced Raman scattering

Nikolaos T. Panagiotopoulos; N. Kalfagiannis; K C Vasilopoulos; N. Pliatsikas; S. Kassavetis; G. Vourlias; M A Karakassides; P. Patsalas

Perhaps the simplest method for creating metal nanoparticles on a substrate is by driving their self-assembly with the thermal annealing of a thin metal film. By properly tuning the annealing parameters one hopes to discover a recipe that allows the pre-determined design of the NP arrangement. However, thermal treatment is known for detrimental effects and is not really the manufacturers route of choice when it comes to large-scale applications. An alternative method is the use of microwave annealing, a method that has never been applied for metal processing, due to the high reflectance of microwave radiation at the surface of a metal. However, in this work we challenge the widely used nanostructuring methods by proving the microwaves annealing ability to produce plasmonic templates, out of extremely thin metal films, by simply using a domestic microwave oven apparatus. We show that this process is generic and independent of the deposition method used for the metal and we further quantify the suitability of these plasmonic templates for use in surface-enhanced Raman scattering applications.


ACS Applied Materials & Interfaces | 2010

Bare-Eye View at the Nanoscale: New Visual Interferometric Multi-Indicator (VIMI)

Nikolaos T. Panagiotopoulos; P. Patsalas; Constantinos Prouskas; Georgios P. Dimitrakopulos; Philomela Komninou; Theodoros Karakostas; Adrian P. Tighe; Elefterios Lidorikis

By exploiting the interferometric antireflection action of a probe sample, consisting of a diamond-like carbon (DLC) film grown on Si, combined with a specific illumination spectrum, we designed and constructed an optical device for the visual remote sensing of radiation (either plasma or atomic oxygen) and for the visual inspection of adsorbed organic contamination as thin as a few molecular layers. The capabilities of this new visual interferometric multi-indicator (VIMI) enable the bare-eye color detection of thickness changes on the order of a few nanometers without the intervention of any instrumental or computer interface.


Archive | 2015

Ca, P and Collagen Fibrils Period Measurements in the Vertebras of Lordotic Sparus aurata

Panagiotis Berillis; Nikolaos T. Panagiotopoulos

Skeletal deformities of Gilthead seabream (Sparus aurata) is a major factor that effects the production cost, the external morphology of the fish as well as its survival and growth. Adult individuals of S. aurata were collected from a commercial fish farm and were divided into two groups. One with the presence of lordosis and one without any skeletal deformity. Fishes X-rayed and vertebras were taken from the site of the vertebra column that the lordosis occurred. One part was decalcified and prepared for collagen examination with transmission electron microscope and the rest incinerated and Ca and P contents were measured. The stoichiometries of the samples were obtained by EDS. The same procedure was followed for fish without any skeletal deformity (vertebras were taken from the middle part of the vertebra column). The decalcified vertebras parts examined with TEM, collagen micrographs were taken and the fibrils’ period was measured. Statistics revealed no significant difference for both Ca and P or the collagen fibrils’ period between the two fish groups.


Solar Energy Materials and Solar Cells | 2012

Plasmonic silver nanoparticles for improved organic solar cells

N. Kalfagiannis; Panagiotis Karagiannidis; C. Pitsalidis; Nikolaos T. Panagiotopoulos; C. Gravalidis; S. Kassavetis; P. Patsalas; S. Logothetidis


Materials & Design | 2016

Nanoporous silver for electrocatalysis application in alkaline fuel cells

Daria Barsuk; Anicet Zadick; Marian Chatenet; Konstantinos Georgarakis; Nikolaos T. Panagiotopoulos; Yannick Champion; Alberto Moreira Jorge


Thin Solid Films | 2014

Performance of hybrid buffer Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) layers doped with plasmonic silver nanoparticles

N. Kalfagiannis; Panagiotis Karagiannidis; C. Pitsalidis; N. A. Hastas; Nikolaos T. Panagiotopoulos; P. Patsalas; S. Logothetidis


Microporous and Mesoporous Materials | 2016

Nanoporous titanium obtained from a spinodally decomposed Ti alloy

Nikolaos T. Panagiotopoulos; A. Moreira Jorge; I. Rebai; Konstantinos Georgarakis; W.J. Botta; A.R. Yavari


Scripta Materialia | 2017

Novel micro-flat springs using the superior elastic properties of metallic glass foils

Yousfi; Nikolaos T. Panagiotopoulos; A.M. Jorge Junior; Konstantinos Georgarakis; Alain Reza Yavari


Materials & Design | 2016

Mechanically induced waves in metallic glass foils

Nikolaos T. Panagiotopoulos; Yousfi; Konstantinos Georgarakis; Alain Reza Yavari

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P. Patsalas

Aristotle University of Thessaloniki

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Alain Reza Yavari

Centre national de la recherche scientifique

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N. Kalfagiannis

Nottingham Trent University

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Yousfi

Centre national de la recherche scientifique

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C. Pitsalidis

Aristotle University of Thessaloniki

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Panagiotis Karagiannidis

Aristotle University of Thessaloniki

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S. Kassavetis

Aristotle University of Thessaloniki

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S. Logothetidis

Aristotle University of Thessaloniki

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Daria Barsuk

Centre national de la recherche scientifique

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