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Infrared Region (infrared + region)

Distribution by Scientific Domains
Physics and Astronomy55%
Polymers and Materials Science44%

Selected Abstracts

Near IR Sensitization of Organic Bulk Heterojunction Solar Cells: Towards Optimization of the Spectral Response of Organic Solar Cells

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2010
Markus Koppe
Abstract The spectroscopic response of a poly(3-hexylthiophene)/[6,6]-phenyl-C61 -butyric acid methyl ester (P3HT/PCBM)-based bulk heterojunction solar cell is extended into the near infrared region (NIR) of the spectrum by adding the low bandgap polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H -cyclopenta[2,1- b;3,4- b´]-dithiophene)- alt -4,7-(2,1,3-benzothiadiazole)] [PCPDTBT] to the blend. The dominant mechanism behind the enhanced photosensitivity of the ternary blend is found to be a two-step process: first, an ultrafast and efficient photoinduced charge transfer generates positive charges on P3HT and PCPDTBT and a negative charge on PCBM. In a second step, the positive charge on PCPDTBT is transferred to P3HT. Thus, P3HT serves two purposes. On the one hand it is involved in the generation of charge carriers by the photoinduced electron transfer to PCBM, and, on the other hand, it forms the charge transport matrix for the positive carriers transferred from PCPDTBT. Other mechanisms, such as energy transfer or photoinduced charge transfer directly between the two polymers, are found to be absent or negligible. [source]

Luminescence of Nanocrystalline Erbium-Doped Yttria

ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009
Yuanbing Mao
Abstract In this paper, the luminescence, including photoluminescence, upconversion and cathodoluminescence, from single-crystalline erbium-doped yttria nanoparticles with an average diameter of 80,nm, synthesized by a molten salt method, is reported. Outstanding luminescent properties, including sharp and well-resolved photoluminescent lines in the infrared region, outstanding green and red upconversion emissions, and excellent cathodoluminescence, are observed from the nanocrystalline erbium-doped yttria. Moreover, annealing by the high power laser results in a relatively large increase in photoluminescent emission intensity without causing spectral line shift. These desirable properties make these nanocrystals promising for applications in display, bioanalysis and telecommunications. [source]

A Conjugated Polymer for Near Infrared Optoelectronic Applications,

ADVANCED MATERIALS, Issue 20 2007
E. Perzon
A new conjugated polymer, LBPP-1, with an unusually low band-gap (ca.,1.0,eV) is presented. Light absorption and photovoltaic response up to 1200,nm in composites with a fullerene is demonstrated. Solar cell performance is presented and the polymer's suitability for photodetection in the infrared region is discussed. [source]

Semiconductor Carbon Nanotubes as Ultrafast Switching Materials for Optical Telecommunications,

ADVANCED MATERIALS, Issue 6 2003
S. Tatsuura
The third-order nonlinear optical property ,(3)I of a film of single-walled carbon nanotubes was studied in the infrared region. The film combines a high ,(3)I (,0.85,×,10,7 esu at resonant wavelength) with a rapid transmittance recovery (from differential transmission spectra, see Figure), making it suitable for highly efficient and ultrafast devices for optical telecommunications. [source]

Advances in laser technology for isolated attosecond pulse generation

LASER PHYSICS LETTERS, Issue 4 2009
C. Vozzi
Abstract In this review we report on recent advances in laser technology, which have contributed to the fast development of attosecond science. In particular we will concentrate on two experimental methods for the generation of high-peak-power, fewoptical-cycle laser pulses with controlled electric field, which are crucial for the generation of isolated attosecond pulses. The first method is the hollow-fiber compression technique, introduced in 1996 and now routinely used in several laboratories. So far, isolated attosecond pulses have been generated by using few-cycle pulses produced by such compression technique, in combination with active stabilization of the carrier-envelope phase. More recently, few-cycle pulses tunable in the infrared region have been generated by optical parametric amplification with passive stabilization of the carrier-envelope phase. Such parametric sources represent excellent drivers for the generation of harmonic radiation with an extended cutoff, and offer the possibility to extend attosecond science towards the soft-X rays region. Finally, we will briefly discuss the basic elements of attosecond metrology. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Experimental Ti i oscillator strengths and their application to cool star analysis

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006
R. J. Blackwell-Whitehead
ABSTRACT We report experimental oscillator strengths for 88 Ti i transitions covering the wavelength range 465,3892 nm, 67 of which had no previous experimental values. Radiative lifetimes for 13 energy levels, including the low energy levels 3d2(3F) 4s4p (3P) z 5D°j, have been measured using time-resolved laser-induced fluorescence. Intensity-calibrated Ti i spectra have been measured using Fourier transform spectroscopy to determine branching fractions for the decay channels of these levels. The branching fractions are combined with the radiative lifetimes to yield absolute transition probabilities and oscillator strengths. Our measurements include 50 transitions in the previously unobserved infrared region , > 1.0 ,m, a region of particular interest to the analysis of cool stars and brown dwarfs. [source]

Low temperature growth of transparent conducting ZnO films by plasma assisted deposition

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2006
A. Nishii
Abstract Transparent conducting ZnO films are deposited by plasma assisted deposition technique on glass and plastic substrates at temperatures 60 , 300 °C using metallic Zn, metallic Ga and plasma-excited oxygen as source materials. Deposited films were characterized by X-ray diffraction (XRD), optical transmittance in the visible and infrared region, Raman scattering, and Hall measurements. Film properties are controlled by substrate temperature, oxygen source/zinc source supply ratio, and Ga doping. 350 nm-thick Ga-doped ZnO films deposited at 290 °C showed low resistivity (,2 × 10,4 , cm) and high transmittance in the visible region (,85%). (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fabrication of a n -type ZnO/p -type Cu,Al,O heterojunction diode by sputtering deposition methods

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2009
Satoru Takahata
Abstract CuAlO2 polycrystalline films were deposited by the helicon-wave-excited plasma sputtering (HWPS) method at 700 °C. The best full-width at half-maximum value of the (006) CuAlO2 X-ray diffraction peak was 0.19 degrees, which was similar to those reported previously using other deposition methods. While, noncrystalline Cu,Al,O films were deposited by a conventional RF sputtering method. Using this p -type transparent conducting oxide (TCO) film and an n -type ZnO film deposited by HWPS, a n -type ZnO/p -type Cu,Al,O heterojunction diode was fabricated. Optical transmittance of the device was approximately 80% in the near infrared region. The rectifying current,voltage characteristics with a threshold forward voltage approximately 1.4 V were obtained. These results are the first step toward realizing an electrical/optical device using p -type CuAlO2 or Cu-Al-O films. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Polytype control and properties of AlN on silicon

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005
V. Cimalla
Abstract In this paper we report on the optical and structural characterisation of cubic polytype AlN thin films on 3C-SiC/Si(111) pseudo-substrates prepared by carbonisation. We have found that 3C-AlN phase can be stabilised on the "waved" 3C-SiC(111) surface by polytype replication. On the other hand, 2H-AlN was grown on atomically smooth surfaces. X-ray diffraction and transmission electron microscopy imply that the cubic AlN was grown along with hexagonal inclusions up to 20%. Spectroscopic ellipsometry in the infrared region show the typical phonon lines for the two polytypes. The appearance of the TO phonon at 646 cm,1 confirms the existence of 3C-AlN. In the ultraviolet region the critical points in the band structure were identified. For 3C- and 2H-AlN the first direct transition at the ,-point was determined to be at 5.74 eV and 6.16 eV, respectively. No indirect transition at lower energies was detected. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]