Browsing by Subject "Absorption"

Article

Absorption-enhanced reforming of phenol by steam over supported Fe catalysts

Polychronopoulou, Kyriaki; Bakandritsos, Aristides; Tzitzios, Vasileios; Fierro, José Luis García; Efstathiou, Angelos M. (2006)

Supported Fe catalysts of varying support chemical composition prepared by sol-gel and incipient wetness impregnation methods were studied for the steam reforming of phenol (one of the main constituents of tar produced ...

Article

Analysis of the excited-state absorption spectral bandshape of oligofluorenes

Hayes, Sophia C.; Silva, C. (2010)

We present ultrafast transient absorption spectra of two oligofluorene derivatives in dilute solution. These spectra display a photoinduced absorption band with clear vibronic structure, which we analyze rigorously using ...

Article

Carrier dynamics in InS nanowires grown via chemical vapor deposition

Othonos, A.; Zervos, Matthew (2010)

Transient femtosecond absorption spectroscopy and timecorrelating single photon counting (TCSPC) photoluminescence (PL) were employed to study InS nanowires (NWs) grown by chemical vapor deposition (CVD) and determine the ...

Article

Carrier dynamics in InS nanowires grown via chemical vapor deposition

Othonos, Andreas S.; Zervos, Matthew (2010)

Transient femtosecond absorption spectroscopy and timecorrelating single photon counting (TCSPC) photoluminescence (PL) were employed to study InS nanowires (NWs) grown by chemical vapor deposition (CVD) and determine the ...

Article

Carrier dynamics in Β-Ga2O3 nanowires

Othonos, A.; Zervos, Matthew; Christofides, C. (2010)

Carrier dynamics have been investigated in Β-Ga2O 3 nanowires (NWs) grown by the vapor-liquid-solid mechanism, using ultrashort transient absorption spectroscopy in conjunction with time-correlating single photon counting ...

Article

Carrier relaxation dynamics in SnxNy nanowires grown by chemical vapor deposition

Othonos, A.; Zervos, Matthew (2009)

Carrier relaxation dynamics in tin nitride (SnxNy) nanowires have been investigated using femtosecond transient absorption spectroscopy. The nanowires were grown directly on quartz using chemical vapor deposition and had ...

Article

Carrier relaxation dynamics in SnxNy nanowires grown by chemical vapor deposition

Othonos, Andreas S.; Zervos, Matthew (2009)

Carrier relaxation dynamics in tin nitride (SnxNy) nanowires have been investigated using femtosecond transient absorption spectroscopy. The nanowires were grown directly on quartz using chemical vapor deposition and had ...

Article

Ceria-based materials for hydrogen production via hydrocarbon steam reforming and water-gas shift reactions

Polychronopoulou, Kyriaki; Kalamaras, Christos M.; Efstathiou, Angelos M. (2011)

This review paper provides an overview of the use of ceria-based catalytic materials towards the industrial hydrogen production via the hydrocarbon steam reforming and the water-gas shift reaction routes with a focus on ...

Article

Defect states of chemical vapor deposition grown GaN nanowires: Effects and mechanisms in the relaxation of carriers

Tsokkou, Demetra; Othonos, Andreas S.; Zervos, Matthew (2009)

Carrier relaxation in GaN nanowires, grown by atmospheric pressure chemical vapor deposition, via direct nitridation of Ga with NH3 at 950 °C has been investigated in detail. Differential absorption measurements reveal a ...

Article

Defect states of chemical vapor deposition grown GaN nanowires: Effects and mechanisms in the relaxation of carriers

Tsokkou, D.; Othonos, A.; Zervos, Matthew (2009)

Carrier relaxation in GaN nanowires, grown by atmospheric pressure chemical vapor deposition, via direct nitridation of Ga with NH3 at 950 °C has been investigated in detail. Differential absorption measurements reveal a ...

Article

Direct observation of excitons in polymer/carbon nanotube composites at room temperature: The influence of nanotube concentration

Lioudakis, Emmanouil E.; Kanari, C.; Othonos, Andreas S.; Alexandrou, Ioannis (2008)

In this work, we have employed spectroscopic ellipsometry technique to study the optical properties of polymer/carbon nanotube (CN) composites as a function of nanotube concentration. Using a two-layer structural model ...

Article

Femtosecond carrier dynamics in In 2O 3 nanocrystals

Othonos, A.; Zervos, Matthew; Tsokkou, D. (2009)

We have studied carrier dynamics in In 2O 3 nanocrystals grown on a quartz substrate using chemical vapor deposition. Transient differential absorption measurements have been employed to investigate the relaxation dynamics ...

Article

Femtosecond carrier dynamics in In 2O 3 nanocrystals

Othonos, Andreas S.; Zervos, Matthew; Tsokkou, Demetra (2009)

We have studied carrier dynamics in In 2O 3 nanocrystals grown on a quartz substrate using chemical vapor deposition. Transient differential absorption measurements have been employed to investigate the relaxation dynamics ...

Article

Femtosecond dynamics in single wall carbon nanotube/poly(3-hexylthiophene) composites

Lioudakis, Emmanouil E.; Othonos, Andreas S.; Alexandrou, Ioannis (2008)

Femtosecond transient absorption measurements on single wall carbon nanotube/poly(3-hexylthiophene) composites are used to investigate the relaxation dynamics of this blended material. The influence of the addition of ...

Article

Hybrid inorganic/organic semiconductor heterostructures with efficient non-radiative energy transfer

Heliotis, G.; Itskos, Grigorios; Murray, R.; Dawson, M. D.; Watson, I. M.; Bradley, D. D. C. (2006)

A hybrid inorganic/organic semiconductor structure employing a polyfluorene thin films with Efficient non-radiative Förster resonant energy transfer (FRET) was fabricated. FRET is mediated by dipole-dipole interactions, ...

Article

An inverse method to assign receptances by using classical vibration absorbers

Zhu, J.; Mottershead, J. E.; Kyprianou, Andreas (2009)

The classical mass-spring absorber can be thought of as a very simple structural modification. In this paper the inverse problem of assigning receptances to a dynamic system by using one or more simple mass-spring absorbers ...

Article

Linear dynamic polarizability and the absorption spectrum of an exciton in a quantum ring in a magnetic field

Ghazaryan, A. V.; Djotyan, Anahit P.; Moulopoulos, Konstantinos; Kirakosyan, Albert A. (2011)

The problem of an electron-hole system interacting through a contact potential and moving in a one-dimensional quantum ring threaded by an Aharonov-Bohm flux is considered, with respect to the system's energetics as well ...

Article

Minority-spin band parameters in a NiMnSb thin film determined by spectral conductivity

Grigorescu, C. E. A.; Trodahl, H. J.; Strickland, N. M.; Bittar, A.; Manea, S. A.; Giapintzakis, John; Monnereau, O.; Notonier, R.; Kennedy, V. J. (2004)

NiMnSb is expected to be a ferromagnetic half metal, an expectation that is based in part on band structure calculations. Here we report optical conductivity studies of the band structure for a film prepared by pulsed laser ...

Article

Monitoring charge exchange in P3HT-nanotube composites using optical and electrical characterisation

Alexandrou, Ioannis; Lioudakis, Emmanouil E.; Delaportas, Dimitrios; Zhao, C. Z.; Othonos, Andreas S. (2009)

Charge exchange at the bulk heterojunctions of composites made by mixing single wall nanotubes (SWNTs) and polymers show potential for use in optoelectronic devices such as solar cells and optical sensors. The density/total ...

Article

Observation of the equilibrium CuB-CO complex and functional implications of the transient heme a3 propionates in cytochrome ba3-CO from Thermus thermophilus. Fourier transform infrared (FTIR) and time-resolved step-scan FTIR studies

Koutsoupakis, Constantinos; Stavrakis, Stavros; Pinakoulaki, Eftychia; Soulimane, T.; Varotsis, Constantinos (2002)

We report the first evidence for the existence of the equilibrium CuB 1+-CO species of CO-bound reduced cytochrome ba3 from Thermus thermophilus at room temperature. The frequency of the C-O stretching mode of CuB 1+-CO ...