Optical properties of colloidal InGaP∕ZnS core/shell nanocrystals

Joshi, Abhishek; Manasreh, M. O.; Davis, Edwin Adams; Weaver, B. D.

doi:10.1063/1.2354031

Cited by 13 publications

(7 citation statements)

References 16 publications

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“…The optical band gaps E g of both compounds were determined from their absorption in thin solid film following the method of reference. [36] The E g value obtained from UV spectrum is 3.26 eV.…”

Section: Photophysics and Photophysical Properties In Solutionsmentioning

confidence: 99%

Fluorescence Confocal Polarizing Microscopy of a Fluorescent Bent‐Core Liquid Crystal Exhibiting Polarization Splay Modulated (B7) Structures and Defects

et al. 2014

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The B7 phases of bent-core molecules are polarization splay modulated fluid smectics that exhibit an unusually complex variety of exotic macroscopic structures, textures, and defects visible in polarized light microscopy. Herein we describe optical studies of these structures using fluorescence confocal polarizing microscopy (FCPM) and depolarized transmission optical microscopy to probe their organization in three dimensions. These experiments utilize recently reported fluorescent bent-core molecules designed to give strong polarized fluorescence. This new bent-core molecular family provides the means for probing a variety of bent-core phases and structures by using FCPM and multiphoton fluorescence nonlinear imaging techniques. Comparative textural analysis of the B7 structures obtained using different types of imaging and the corresponding structural models are discussed.

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Section: Photophysics and Photophysical Properties In Solutionsmentioning

confidence: 99%

Fluorescence Confocal Polarizing Microscopy of a Fluorescent Bent‐Core Liquid Crystal Exhibiting Polarization Splay Modulated (B7) Structures and Defects

et al. 2014

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“…Therefore, protons go through the whole film thickness releasing an amount of energy of 817 keV, equivalent to the integral of the energy loss curve reported in Figure b. In order to calculate the average dose released per QD, the weight of the single dot was evaluated by taking a value of Ga fraction ranging from 52 to 55% and a ZnS shell thickness of about 40% with respect to the InGaP core . Moreover, the overall nanocrystal size of 4 nm was measured with a TEM analysis (Figure c).…”

Section: Methodsmentioning

confidence: 99%

“…In order to calculate the average dose released per QD, the weight of the single dot was evaluated by taking a value of Ga fraction ranging from 52 to 55% and a ZnS shell thickness of about 40% with respect to the InGaP core. 27 Moreover, the overall nanocrystal size of 4 nm was measured with a TEM analysis (Figure 1c). In this way, a concentration of 1.2 × 10 15 QD/cm 3 was evaluated.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Proton Irradiation Effects on Colloidal InGaP/ZnS Core–Shell Quantum Dots Embedded in Polydimethylsiloxane: Discriminating Core from Shell Radiation-Induced Defects through Time-Resolved Photoluminescence Analysis

et al. 2018

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In scintillation and dosimetry applications, the increasing interest on the use of colloidal quantum dots (QDs) in comparison with organic fluorophores is mainly due to their easier chemical processability, narrower photoluminescence (PL) emission, and higher cross-section for ionizing radiation. The development of scintillators and dosimeter based on QDs, however, relies on a deep understanding of the effects of ionizing radiation on QD structures. In this paper, we present the optical characterization of colloidal cadmium-free InGaP/ZnS core−shell QDs embedded in polydimethylsiloxane (PDMS) and irradiated with 2 MeV protons (H + ) in the fluence range of 10 14 to 10 15 H + cm −2 . Steady-state PL measurements of the irradiated samples show a decrease of the average QD PL intensity, indicating the introduction of PL quenching centers. Time-resolved PL measurements, acquired with a time-correlated single photon counting system, provide a way to probe the radiation-induced change in the carrier recombination dynamics of the QDs. A detailed analysis of the time-resolved PL curves demonstrates the presence of PL quenching defects localized both at the inner (core) and at the outer (shell) structure of the nanocrystal. The radiation-induced change in the QD optical properties, coupled with a suitable radiation hardness of the PDMS in these irradiation conditions, open the way for possible future applications related to dosimetry systems based on QDs as nanostructured sensing elements.

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“…The optical band gaps (E g ) of all compounds were determined by their corresponding absorption in thin lms, using a method reported in the literature. 23 The optical band gaps of these compounds (E g ) varied from 3.6 to 3.7 eV.…”

Section: Photophysical Propertiesmentioning

confidence: 99%

H-bonded complexes containing 1,3,4-oxadiazole derivatives: mesomorphic behaviour, photophysical properties and chiral photoinduction

et al. 2014

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Two series of new V-shaped acids derived from 1,3,4-oxadiazoles are described. These acids were used to prepare supramolecular complexes through hydrogen bonding with 2,4-diamino-6-dodecylamino-1,3,5triazine in a 3 : 1 ratio, respectively. The formation of the complexes was studied by infrared and NMR techniques. The thermal behaviour and mesomorphic properties of all the complexes were investigated by polarized light optical microscopy, differential scanning calorimetry and X-ray diffraction. Hexagonal and rectangular columnar mesophases were observed for all complexes at room temperature, without evidence of crystallization. The results of circular dichroism studies allowed us to propose that in the liquid crystalline state these materials adopt a helical columnar organization and this chirality can be controlled by irradiation with CPL. Furthermore, the complexes display strong blue luminescence in solution and in the mesophase.

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Optical properties of colloidal InGaP∕ZnS core/shell nanocrystals

Abstract: Articles you may be interested inAlInP-based rolled-up microtube resonators with colloidal nanocrystals operating in the visible spectral range Appl.

Cited by 13 publications

References 16 publications

Fluorescence Confocal Polarizing Microscopy of a Fluorescent Bent‐Core Liquid Crystal Exhibiting Polarization Splay Modulated (B7) Structures and Defects

Fluorescence Confocal Polarizing Microscopy of a Fluorescent Bent‐Core Liquid Crystal Exhibiting Polarization Splay Modulated (B7) Structures and Defects

Proton Irradiation Effects on Colloidal InGaP/ZnS Core–Shell Quantum Dots Embedded in Polydimethylsiloxane: Discriminating Core from Shell Radiation-Induced Defects through Time-Resolved Photoluminescence Analysis

H-bonded complexes containing 1,3,4-oxadiazole derivatives: mesomorphic behaviour, photophysical properties and chiral photoinduction

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