Photo-oxidation-enhanced coupling in densely packed CdSe quantum-dot films

We model the blueshift of the photoluminescence spectra of CdSe‐ZnS nanocrystals under ultraviolet irradiation. The model is based on photo‐assisted oxygen diffusion into the CdSe nanocrystal structure, which is believed to have a primary role in the observed blueshift of the photoluminescence peak wavelength by reducing the confinement core radius of the exciton wavefunction inside the CdSe nanocrystal core. We compare the predictions of this model with experimental data (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…where λ 0 is the initial wavelength and B is the decay parameter [3]. As shown below, a similar dependence is observed in the present study.…”

Section: Introductionsupporting

confidence: 85%

Modelling photooxidation of CdSe‐ZnS nanocrystals

Koháry

Gibson

2011

Phys. Status Solidi C

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“…In addition, NCs exhibit a range of intriguing photophysical properties. In particular, there have been a number of recent reports that the fluorescence intensity of NCs can actually be enhanced in the presence of air, [2][3][4] in marked contrast to, for example, organic semiconductors, which generally photo-oxidize and bleach irreversibly in air. Surprisingly, no corresponding fluorescence increase has previously been observed from single particles upon exposure to air.…”

Section: V Talapin and H Wellermentioning

confidence: 96%

Air-induced fluorescence bursts from single semiconductor nanocrystals

Müller

Lupton

Rogach

et al. 2004

Applied Physics Letters

120

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We observe a dramatic enhancement of the fluorescence intensity from single core∕shell CdSe∕ZnS nanocrystals upon sudden exposure to air from an evacuated surrounding. Both the number of particles contributing to emission increases as well as the average emission intensity from a single particle, leading to an overall fluorescence rise by a factor of 60. A common power-law distribution of both on- and off times of single nanocrystals is observed independent of shell thickness and environment. We propose that electron transfer to oxygen, which is facilitated by the presence of water, leads to a neutralization of charged, nonemissive nanocrystals.

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“…Several research groups claimed that the incorporation of QDs into a solid matrix can lead to a blue-shift in both their absorption and emission, caused by surface oxidation of the QD during the manufacturing process. [89,136,139] In addition to a blue-shift in emission wavelength, the emission intensity in QD solar concentrators also is dependent on the nature of the host matrix. For example, CdSe/ZnS QDs in a solid matrix lose 22.5-96% of the emission intensity they exhibited in solution.…”

Section: Quantum Dotsmentioning

confidence: 99%

Thirty Years of Luminescent Solar Concentrator Research: Solar Energy for the Built Environment

Debije

Verbunt

2011

Advanced Energy Materials

804

689

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Research on the luminescent solar concentrator (LSC) over the past thirty‐odd years is reviewed. The LSC is a simple device at its heart, employing a polymeric or glass waveguide and luminescent molecules to generate electricity from sunlight when attached to a photovoltaic cell. The LSC has the potential to find extended use in an area traditionally difficult for effective use of regular photovoltaic panels: the built environment. The LSC is a device very flexible in its design, with a variety of possible shapes and colors. The primary challenge faced by the devices is increasing their photon‐to‐electron conversion efficiencies. A number of laboratories are working to improve the efficiency and lifetime of the LSC device, with the ultimate goal of commercializing the devices within a few years. The topics covered here relate to the efforts for reducing losses in these devices. These include studies of novel luminophores, including organic fluorescent dyes, inorganic phosphors, and quantum dots. Ways to limit the surface and internal losses are also discussed, including using organic and inorganic‐based selective mirrors which allow sunlight in but reflect luminophore‐emitted light, plasmonic structures to enhance emissions, novel photovoltaics, alignment of the luminophores to manipulate the path of the emitted light, and patterning of the dye layer to improve emission efficiency. Finally, some possible ‘glimpses of the future’ are offered, with additional research paths that could result in a device that makes solar energy a ubiquitous part of the urban setting, finding use as sound barriers, bus‐stop roofs, awnings, windows, paving, or siding tiles.

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Photo-oxidation-enhanced coupling in densely packed CdSe quantum-dot films

Cited by 49 publications

References 23 publications

Modelling photooxidation of CdSe‐ZnS nanocrystals

Modelling photooxidation of CdSe‐ZnS nanocrystals

Air-induced fluorescence bursts from single semiconductor nanocrystals

Thirty Years of Luminescent Solar Concentrator Research: Solar Energy for the Built Environment

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