Size dependent optical properties of the CdSe-CdS core-shell quantum dots in the strong confinement regime
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Title |
Size dependent optical properties of the CdSe-CdS core-shell quantum dots in the strong confinement regime
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Creator |
MATHEW, S
SARAN, AD BHARDWAJ, BS JOSEPH, SA RADHAKRISHNAN, P NAMPOORI, VPN VALLABHAN, CPG BELLARE, JR |
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Subject |
NANOPARTICLES
NANOCRYSTALS NONLINEARITIES MICROEMULSION ABSORPTION SEMICONDUCTORS INTENSITY CLUSTERS POLYMER SHAPE |
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Description |
We have investigated the third-order optical nonlinearity in CdSe and CdSe-CdS core-shell quantum dots with particle sizes in the range 4.4-5.2 nm by the z-scan technique. Optical absorption and fluorescence properties show quantum confinement effect and the fluorescence peak is shifted when the diameter of the core-shell quantum dots becomes large. Their nonlinear absorption and nonlinear refraction were observed with nanosecond laser radiation of 532-nm wavelength. At an excitation irradiance of 392MW/cm(2), the CdSe-CdS core-shell quantum dots exhibit a reverse saturation and a negative nonlinear refractive index indicating a clear nonlinear behavior. The introduction of CdS shell around CdSe core gives large third-order nonlinearity and third-order optical susceptibility decreases with increasing particle core size in the case of core-shell quantum dots within the range of our investigations. The third-order susceptibility of these quantum dots vary from 3.39 x 10(-11) to 5.77 x 10(-11) esu. The optical limiting threshold of the quantum dots varies in the range from 0.298 to 0.345GW/cm(2) and this therefore makes CdSe-CdS core-shell quantum dots a promising candidate for reverse-saturable absorption based devices at high laser intensities such as optical limiters. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3702430]
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Publisher |
AMER INST PHYSICS
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Date |
2014-10-15T16:01:29Z
2014-10-15T16:01:29Z 2012 |
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Type |
Article
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Identifier |
JOURNAL OF APPLIED PHYSICS, 111(7)
http://dx.doi.org/10.1063/1.3702430 http://dspace.library.iitb.ac.in/jspui/handle/100/15219 |
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Language |
en
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