The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Prasun K. Mandal - One of the best experts on this subject based on the ideXlab platform.
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highly photoluminescent inp based core alloy shell qds from air stable precursors Excitation Wavelength dependent photoluminescence quantum yield photoluminescence decay dynamics and single particle blinking dynamics
Journal of Physical Chemistry C, 2018Co-Authors: Tapan Routh, Debjit Roy, Saptarshi Mandal, Prasun K. MandalAbstract:InP based quantum dots (QDs) are coming in a big way as an alternative to toxic Cd, or Pb based QDs. Unlike many literature reports in this work, green-yellow-orange-red emitting highly photoluminescent (PLQY as high as 65%) and photostable InP/ZnSeS core/alloy shell quantum dots (CAS QDs) have been synthesized using a less toxic, air-stable aminophosphine precursor (P(DMA)3). Unlike literature predictions in this paper, we show that green-yellow-orange-red emitting InP based alloyed QDs can be prepared with InCl3 only. We report here the hitherto unobserved and quite interesting Excitation Wavelength dependent PLQY for all of these green-yellow-orange-red emitting InP based CAS QDs. PLQY increases monotonically with increasing Excitation Wavelength. Significant deviation of the PL Excitation spectrum from the absorption spectrum has been observed in the shorter Wavelength region. This observation is perhaps because the surface mediated nonradiative pathways predominate over radiative charge carrier recom...
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Excitation Wavelength dependent fluorescence behavior of the room temperature ionic liquids and dissolved dipolar solutes
Journal of Photochemistry and Photobiology A: Chemistry, 2006Co-Authors: Prasun K. Mandal, Aniruddha Paul, Anunay SamantaAbstract:Room temperature ionic liquids are novel media for a variety of studies and applications. In this article, the Excitation Wavelength dependent fluorescence behavior of imidazolium ionic liquids and dipolar solutes dissolved in these liquids is highlighted. We discuss the origin of the unconventional fluorescence behavior of the ionic liquids and also of the dipolar systems, most of which show no Excitation Wavelength dependence in the conventional solvents. The implications of these observations in fluorescence studies involving the ionic liquids are discussed.
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Excitation-Wavelength-Dependent Fluorescence Behavior of Some Dipolar Molecules in Room-Temperature Ionic Liquids
The Journal of Physical Chemistry A, 2004Co-Authors: Prasun K. Mandal, Moloy Sarkar, Anunay SamantaAbstract:The fluorescence behavior of several dipolar molecules has been studied in three room-temperature ionic liquids, namely, [BMIM][BF4], [EMIM][BF4], and [BMIM][PF6], as a function of the Excitation Wavelength. Although a large majority of these systems show normal fluorescence behavior with no Excitation Wavelength dependence, a few systems surprisingly exhibit fairly strong Excitation-Wavelength-dependent fluorescence behavior in these media. The Excitation-Wavelength-dependent shift of the fluorescence maximum is measured to be between 10 and 35 nm. The various fluorescence parameters of the systems have been carefully examined to determine the factors that contribute to this kind of behavior, generally not observed in conventional media. It is shown that the existence of a distribution of energetically different molecules in the ground state coupled with a low rate of the excited-state relaxation processes, viz., solvation and energy transfer, are responsible for the Excitation-Wavelength-dependent fluor...
Stephen R. Leone - One of the best experts on this subject based on the ideXlab platform.
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Excitation Wavelength dependent small polaron trapping of photoexcited carriers in α fe2o3
Nature Materials, 2017Co-Authors: Scott K. Cushing, Stephen R. Leone, Lucas M Carneiro, Chong Liu, Peidong Yang, Paul A AlivisatosAbstract:Small polaron formation is known to limit ground-state mobilities in metal oxide photocatalysts. However, the role of small polaron formation in the photoexcited state and how this affects the photoconversion efficiency has yet to be determined. Here, transient femtosecond extreme-ultraviolet measurements suggest that small polaron localization is responsible for the ultrafast trapping of photoexcited carriers in haematite (α-Fe2O3). Small polaron formation is evidenced by a sub-100 fs splitting of the Fe 3p core orbitals in the Fe M2,3 edge. The small polaron formation kinetics reproduces the triple-exponential relaxation frequently attributed to trap states. However, the measured spectral signature resembles only the spectral predictions of a small polaron and not the pre-edge features expected for mid-gap trap states. The small polaron formation probability, hopping radius and lifetime varies with Excitation Wavelength, decreasing with increasing energy in the t2g conduction band. The Excitation-Wavelength-dependent localization of carriers by small polaron formation is potentially a limiting factor in haematite's photoconversion efficiency.
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Excitation-Wavelength Dependence of Fluorescence Intermittency in CdSe Nanorods
ACS nano, 2008Co-Authors: Kenneth L. Knappenberger, Daryl B. Wong, Adam M. Schwartzberg, Abraham Wolcott, Jin Z. Zhang, Stephen R. LeoneAbstract:The influence of Excitation Wavelength and embedding media on fluorescence blinking statistics of 4 nm × 20 nm cadmium selenide (CdSe) nanorods is investigated. Photon antibunching (PAB) experiments confirm nonclassical emission from single CdSe nanorods that exhibit a radiative lifetime of 26 ± 13 ns. The blinking data show behaviors that can be categorized into two classes: Excitation near the energy of the band gap and at energies exceeding 240 meV above the band gap. Excitation at the band gap energy (λ ≥ 560 nm) results in more pronounced “on” time probabilities in the distribution of “on” and “off” events, while those resulting from Excitation exceeding the band gap by 240 meV or more (λ ≤ 560 nm) are 200 times less likely to display continuous “on” fluorescence persisting beyond 4 s. The “off” time statistics are also sensitive to the Excitation Wavelength, showing a similar, but inversely correlated, effect. To understand better the Excitation-Wavelength dependence, fluorescence measurements are o...
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Excitation Wavelength dependence of fluorescence intermittency in CdSe/ZnS core/shell quantum dots.
Nano letters, 2007Co-Authors: Kenneth L. Knappenberger, Daryl B. Wong, Yaroslav E. Romanyuk, Stephen R. LeoneAbstract:Core/shell CdSe/ZnS quantum dot fluorescence-blinking statistics depend strongly on Excitation Wavelength. Excitation on the band gap (575 nm) results in inverse-power law "on" time distributions. However, distributions resulting from Excitation above the band gap (525 nm) require a truncated power law and are 100 times less likely to display 10-s fluorescence. "Off" time statistics are insensitive to the Excitation Wavelength. The results may be explained by nonemissive trap states accessed with the higher-photon Excitation energies.
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Excitation Wavelength dependence of fluorescence intermittency in cdse zns core shell quantum dots
Nano Letters, 2007Co-Authors: Kenneth L. Knappenberger, Daryl B. Wong, Yaroslav E. Romanyuk, Stephen R. LeoneAbstract:Core/shell CdSe/ZnS quantum dot fluorescence-blinking statistics depend strongly on Excitation Wavelength. Excitation on the band gap (575 nm) results in inverse-power law "on" time distributions. However, distributions resulting from Excitation above the band gap (525 nm) require a truncated power law and are 100 times less likely to display 10-s fluorescence. "Off" time statistics are insensitive to the Excitation Wavelength. The results may be explained by nonemissive trap states accessed with the higher-photon Excitation energies.
Anunay Samanta - One of the best experts on this subject based on the ideXlab platform.
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Excitation Wavelength dependent fluorescence behavior of the room temperature ionic liquids and dissolved dipolar solutes
Journal of Photochemistry and Photobiology A: Chemistry, 2006Co-Authors: Prasun K. Mandal, Aniruddha Paul, Anunay SamantaAbstract:Room temperature ionic liquids are novel media for a variety of studies and applications. In this article, the Excitation Wavelength dependent fluorescence behavior of imidazolium ionic liquids and dipolar solutes dissolved in these liquids is highlighted. We discuss the origin of the unconventional fluorescence behavior of the ionic liquids and also of the dipolar systems, most of which show no Excitation Wavelength dependence in the conventional solvents. The implications of these observations in fluorescence studies involving the ionic liquids are discussed.
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Excitation-Wavelength-Dependent Fluorescence Behavior of Some Dipolar Molecules in Room-Temperature Ionic Liquids
The Journal of Physical Chemistry A, 2004Co-Authors: Prasun K. Mandal, Moloy Sarkar, Anunay SamantaAbstract:The fluorescence behavior of several dipolar molecules has been studied in three room-temperature ionic liquids, namely, [BMIM][BF4], [EMIM][BF4], and [BMIM][PF6], as a function of the Excitation Wavelength. Although a large majority of these systems show normal fluorescence behavior with no Excitation Wavelength dependence, a few systems surprisingly exhibit fairly strong Excitation-Wavelength-dependent fluorescence behavior in these media. The Excitation-Wavelength-dependent shift of the fluorescence maximum is measured to be between 10 and 35 nm. The various fluorescence parameters of the systems have been carefully examined to determine the factors that contribute to this kind of behavior, generally not observed in conventional media. It is shown that the existence of a distribution of energetically different molecules in the ground state coupled with a low rate of the excited-state relaxation processes, viz., solvation and energy transfer, are responsible for the Excitation-Wavelength-dependent fluor...
Kenneth L. Knappenberger - One of the best experts on this subject based on the ideXlab platform.
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Excitation-Wavelength Dependence of Fluorescence Intermittency in CdSe Nanorods
ACS nano, 2008Co-Authors: Kenneth L. Knappenberger, Daryl B. Wong, Adam M. Schwartzberg, Abraham Wolcott, Jin Z. Zhang, Stephen R. LeoneAbstract:The influence of Excitation Wavelength and embedding media on fluorescence blinking statistics of 4 nm × 20 nm cadmium selenide (CdSe) nanorods is investigated. Photon antibunching (PAB) experiments confirm nonclassical emission from single CdSe nanorods that exhibit a radiative lifetime of 26 ± 13 ns. The blinking data show behaviors that can be categorized into two classes: Excitation near the energy of the band gap and at energies exceeding 240 meV above the band gap. Excitation at the band gap energy (λ ≥ 560 nm) results in more pronounced “on” time probabilities in the distribution of “on” and “off” events, while those resulting from Excitation exceeding the band gap by 240 meV or more (λ ≤ 560 nm) are 200 times less likely to display continuous “on” fluorescence persisting beyond 4 s. The “off” time statistics are also sensitive to the Excitation Wavelength, showing a similar, but inversely correlated, effect. To understand better the Excitation-Wavelength dependence, fluorescence measurements are o...
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Excitation Wavelength dependence of fluorescence intermittency in CdSe/ZnS core/shell quantum dots.
Nano letters, 2007Co-Authors: Kenneth L. Knappenberger, Daryl B. Wong, Yaroslav E. Romanyuk, Stephen R. LeoneAbstract:Core/shell CdSe/ZnS quantum dot fluorescence-blinking statistics depend strongly on Excitation Wavelength. Excitation on the band gap (575 nm) results in inverse-power law "on" time distributions. However, distributions resulting from Excitation above the band gap (525 nm) require a truncated power law and are 100 times less likely to display 10-s fluorescence. "Off" time statistics are insensitive to the Excitation Wavelength. The results may be explained by nonemissive trap states accessed with the higher-photon Excitation energies.
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Excitation Wavelength dependence of fluorescence intermittency in cdse zns core shell quantum dots
Nano Letters, 2007Co-Authors: Kenneth L. Knappenberger, Daryl B. Wong, Yaroslav E. Romanyuk, Stephen R. LeoneAbstract:Core/shell CdSe/ZnS quantum dot fluorescence-blinking statistics depend strongly on Excitation Wavelength. Excitation on the band gap (575 nm) results in inverse-power law "on" time distributions. However, distributions resulting from Excitation above the band gap (525 nm) require a truncated power law and are 100 times less likely to display 10-s fluorescence. "Off" time statistics are insensitive to the Excitation Wavelength. The results may be explained by nonemissive trap states accessed with the higher-photon Excitation energies.
Sheng Hua Liu - One of the best experts on this subject based on the ideXlab platform.
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Excitation Wavelength dependent nearly pure white light emitting crystals from a single gold i containing complex
Organic Letters, 2019Co-Authors: Xiaoyan Wang, Xiaofei Yang, Jun Yin, Zhao Chen, Sheng Hua LiuAbstract:A gold(I) complex is reported. Interestingly, crystals of the gold(I) complex exhibit an excellent Excitation Wavelength-dependent emission effect at room temperature. Notably, a nearly pure white ...
