Optical Properties of CdS and CdTe Sensitized ZnO Nanorods

2014 ◽  
Vol 1707 ◽  
Author(s):  
C. J. Pereyra ◽  
F. Ferrer ◽  
R. E. Marotti ◽  
C. Gómez ◽  
L. Campo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Numerical Simulations ◽  
Diffuse Reflectance ◽  
Zno Nanorods ◽  
Effective Medium ◽  
Red Shift ◽  
Band Edge ◽  
Effective Medium Approximation ◽  
Core Shell ◽  
Sensitive Dependence

ABSTRACTOptical properties of ZnO-CdTe electrochemically prepared on a core-shell nanostructure (NS) were studied. Numerical simulations based on effective medium approximation give higher absorption than ZnO-CdS samples and a sensitive dependence on CdTe content. The absorption edges for deep black samples found by transmittance (T(λ)) and diffuse reflectance (Rdiff(λ)) measurements were at 1.33eV and 1.55eV, respectively. A split-off band edge was also found by Rdiff(λ) at ∼2.5eV. The red shift observed in T(λ), previously observed in ZnO-CdS, and may confirm the enhancement of sub-bandgap absorption due to the NS nature of samples.

scholarly journals Optical absorption enhancement in sensitized ZnO nanorods for solar cells

2015 ◽  
Vol 20 (3) ◽  
pp. 747-756 ◽  
Author(s):  
Carlos Javier Pereyra ◽  
Florencia Ferrer ◽  
Carmela Gómez ◽  
Lucía Campo ◽  
Ricardo Enrique Marotti ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Zno Nanorods ◽  
Solar Spectrum ◽  
Absorption Enhancement ◽  
Effective Medium Approximation ◽  
Core Shell ◽  
Experimental Measurements ◽  
The Core ◽  
Shell Nanostructures ◽  
The One

ABSTRACTThe Optical Properties of ZnO Nanorods (NR) sensitized with different semiconductors in Core-Shell nanostructures were studied, comparing them with those of bare ZnO NR. Experimental measurements of Transmittance and Diffuse Reflectance show an increased light absorption at the solar spectrum and the appearances of new absorption edges (AE). The measurements are compared with numerical simulations based on Bruggeman Effective Medium Approximation. An increased absorption with the sensitizer content is observed. For similar changes in filling fractions, CdTe presents higher changes in absorption than CdS. Shifts in the AE are observed experimentally (e.g. between 2.34 eV and 2.66 eV for CdS). These shifts cannot be assigned to sensitizer content or confinement effects. A similar behaviour is observed for CdTe in which the AE measured by transmittance is between 1.31 eV and 1.36 eV, while the one obtained from Kubelka-Munk analysis of reflectance is, for the same samples, 1.57 eV and 1.49 eV, respectively. Moreover, the split-off AE is also observed at 2.55 eV and 2.28 eV. The observed large red-shifts could be associated with an enhancement of the subbandgap absorption due to an increase in the light free path at the core-shell nanostructure.

Employing the effective medium approximation to model the optical properties of crystallized a-Si:H obtained by MIC

2010 ◽  
pp. NA-NA
Author(s):  
T. F. G. Muller ◽  
D. Knoesen ◽  
C. J. Arendse ◽  
S. Halindintwali ◽  
G. F. Malgas ◽  
...  
Keyword(s):  
Optical Properties ◽  
Effective Medium ◽  
Effective Medium Approximation

A Simple Optical Properties Modeling of Microcrystalline Silicon by the Effective Medium Approximation Method

1996 ◽  
Vol 426 ◽  
Author(s):  
Woo Yeong Cho ◽  
Koeng Su Lim ◽  
Hyun-Mo Cho
Keyword(s):  
Optical Properties ◽  
Approximation Method ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Solar Spectrum ◽  
Effective Medium ◽  
Effective Medium Approximation ◽  
Microcrystalline Silicon ◽  
Two Phase ◽  
P Type

AbstractThe optical properties of microcrystalline silicon (µc-Si) were estimated using the EMA (Effective Medium Approximation) method. This modeling was based on two-phase mixture, amorphous silicon (a-Si) and crystalline silicon (c-Si) with volume fractions of fa and fc respectively. From this modeling, it could be possible to understand thatµc-Si has lower light absorption characteristics than a-Si over all solar spectrum by considering hydrogen involvement in embedded a-Si part of iic-Si and crystalline volume fraction. Also, it is proposed that p-type pe- Si is superior to n-type tic-Si because of its high optical gap of Eo4 and its low absorption coefficient spectrum shape.

Preparation and Characterization of the Core/Shell Structured of CdTe/Ni Fluorescent-Magnetic Particle

2011 ◽  
Vol 217-218 ◽  
pp. 216-219 ◽  
Author(s):  
Shi Chao Xu ◽  
Yue Qian Yang ◽  
Yan Shan Liu ◽  
Heng Miao ◽  
Mei Dong ◽  
...  
Keyword(s):  
Optical Properties ◽  
Hydrazine Hydrate ◽  
Magnetic Core ◽  
Red Shift ◽  
Nano Particles ◽  
Molar Ratio ◽  
Core Shell ◽  
Ni Nanoparticles ◽  
Dna Labeling ◽  
Dual Functional

The niclel nanoparticles were prepared via polyol process with hydrazine hydrate as reductant, the optimum conditions were investigated and proposed to be the molar ratio of NiCl2: NaOH: Hydrazine hydrate =1: 2: 11, 60 °C, pH5.5. The qualified fluorescent-magnetic dual functional CdTe/Ni nanoparticles were synthesized via layer-by-layer (LBL) technique, Ni was designed to be magnetic core and CdTe was used as fluorescent shell material, the molar ratio of CdTe:Ni is 4.5:1. The morphology of the Ni nano particles and CdTe/Ni core shell dual functional nano particles were characterized by transmission electron microscopy (TEM), and optical properties were investigated with fluorescence spectrum (FS) and ultra violet spectrum (UV). The synthesized CdTe/Ni nanoparticles showed yellow fluorescence when excited at 365nm, CdTe/Ni magnetic core shell QDs can be simply precipitated with a common magnet. TEM data indicated that ~15nm of Ni nanoparticles were obtained and ~25nm of CdTe/Ni core shell dual functional nanoparticles were prepared. Red shift of maximum absorbance peak was detected via UV, and these results inferred the QDs growth, moreover, 40nm red shift of maximum emission wavelength from 530nm to 570nm was observed, and which showed the growth QDs and formation of CdTe shell. The prepared magnetic core shell CdTe/Ni nanoparticles showed excellent optical properties, and it is expected to be useful and helpful in DNA sensing based on fluorescence resonance energy transfer, biological separating, and DNA labeling process.

scholarly journals Effective medium approximation of the optical properties of electrochromic cerium-titanium oxide compounds

1997 ◽  
Author(s):  
Nik von Rottkay ◽  
Terry J. Richardson ◽  
Michael Rubin ◽  
J. Slack ◽  
Enrico Masetti ◽  
...  
Keyword(s):  
Optical Properties ◽  
Titanium Oxide ◽  
Effective Medium ◽  
Effective Medium Approximation
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