Luminescence of Individual Porous Si Chromophores

Mason, Michael D.; Credo, Grace M.; Weston, Kenneth D.; Buratto, Steven K.

doi:10.1103/physrevlett.80.5405

Cited by 130 publications

(107 citation statements)

References 21 publications

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“…One of the possible mechanisms by which charging can quench luminescence in alkyl-passivated Si nanocrystallites is described by the "blinking behavior" model advanced by Mason et al, 42 to interpret the luminescence of individual porous Si chromophores. A similar model was also previously used to model the PL of CdSe nanocrystallite quantum dots.…”

Section: Fig 5 ͑A͒mentioning

confidence: 99%

Reactions and luminescence in passivated Si nanocrystallites induced by vacuum ultraviolet and soft-x-ray photons

Chao

Krishnamurthy

Montalti

et al. 2005

Journal of Applied Physics

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Alkyl-modified silicon nanocrystallites are efficient fluorophores which are of interest for fundamental spectroscopic studies and as luminescent probes in biology because of their stability in aqueous media. In this work we have investigated these particles using scanning tunneling microscopy, synchrotron-radiation excited photoemission, and x-ray excited optical luminescence (XEOL). During the course of illumination with 145-eV photons we have monitored the evolution of the Si2p core level and, in samples which have suffered prolonged atmospheric exposure, observed in real time the growth of an extra Si2p component attributed to in situ photoinduced oxidation of the Si nanocrystallites. XEOL reveals that two emission bands are active upon soft-x-ray photon excitation and that photoluminescence intensity decreases with photon exposure, which is attributed to charge trapping within the film. (c) 2005 American Institute of Physics

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Section: Fig 5 ͑A͒mentioning

confidence: 99%

Reactions and luminescence in passivated Si nanocrystallites induced by vacuum ultraviolet and soft-x-ray photons

Chao

Krishnamurthy

Montalti

et al. 2005

Journal of Applied Physics

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“…These two states are identified as 'on' and 'off' 19 . Quantum dots 20 , single molecules 21 , silicon nanocrystals in a porous silicon matrix 22 and others 23 are well-known systems that show blinking. The validity of the two-state on/off model is intensely debated 24 , especially in the context of quantum-dot studies, where, for example, three states 25 and a continuous distribution of states 26 have been reported.…”

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confidence: 99%

Observation and control of blinking nitrogen-vacancy centres in discrete nanodiamonds

et al. 2010

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Nitrogen-vacancy colour centres in diamond can undergo strong, spin-sensitive optical transitions under ambient conditions, which makes them attractive for applications in quantum optics 1 , nanoscale magnetometry 2,3 and biolabelling 4 . Although nitrogen-vacancy centres have been observed in aggregated detonation nanodiamonds 5 and milled nanodiamonds 6 , they have not been observed in very small isolated nanodiamonds 7 . Here, we report the first direct observation of nitrogen-vacancy centres in discrete 5-nm nanodiamonds at room temperature, including evidence for intermittency in the luminescence (blinking) from the nanodiamonds. We also show that it is possible to control this blinking by modifying the surface of the nanodiamonds.Detonation nanodiamond is routinely produced on an industrial scale, and the raw material can be disintegrated into a stable 5-nm monodisperse colloid 8 . The combination of inert core and chemically reactive surface, which can host a variety of moieties, is appealing for chemists, biologists and material scientists 9,10 . Quantum magnetometry 2,3 is an example of an emerging technology that will directly benefit from the availability of nanocrystals with welldefined sizes in the 5-nm range, because the sensitivity to single spins is inversely proportional to the cube of the distance between the sensor (that is, the nitrogen-vacancy (NV) centre) and the spin being detected.Producing and detecting NV colour centres in isolated 5-nm detonation nanodiamond has been controversial, and there has been some scepticism regarding their stability as a useful emitter in a discrete crystal. For example, theoretical calculations of the crystal energy budget favour the location of nitrogen on the surface rather than in the core, which seems to explain the limited observation of NV centres in chemical vapour deposition and high-pressure high-temperature grains of less than 40 nm in size 11,12 , and favours the prediction that nanodiamonds smaller than 10 nm in size do not contain NV centres 7,13 . Although sub-10-nm nanodiamonds with NV centres have been produced using a top-down approach (milling luminescent high-pressure hightemperature microdiamonds into 7-nm particles 6,14 ), the question of NV stability in isolated detonation nanodiamonds persists.In aggregated detonation nanodiamonds (agglomerates and agglutinates 8 ), high-sensitivity, time-gated luminescence and electronic paramagnetic resonance spectroscopy have been used to extract a weak NV signal from a strong luminescence background 5 . The experiments highlight the eclipsing nature of the graphitic surface layers in nanodiamond aggregates-NV centres were simply not visible through the broadband luminescence from the surface and grain boundary material. To distinguish the NV spectral signature from the large grain boundary luminescence overhead, diamond synthesis yielding discrete sub-10-nm detonation nanodiamonds is vital. Here, we use a robust deaggregation and dispersion method, which diminishes the crystal-crystal interaction to...

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“…Another important implication is the assessment of a QD's internal quantum efficiency. 10 When geometric factors are considered they should include the corresponding optical properties of the surrounding materials rather than assume isotropic luminescence.…”

Section: ͑7͒mentioning

confidence: 99%

Effect of substrate proximity on luminescence yield from Si nanocrystals

Sychugov

Galeckas

Elfström

et al. 2006

Applied Physics Letters

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The influence of the proximity of a high refractive index substrate on the luminescence of Si nanocrystals was investigated by time-integrated and time-resolved photoluminescence. The luminescence yield was found to be ϳ2.5 times larger for emitters distanced from the substrate compared to those in proximity with the substrate, while luminescence decay measurements revealed only a slight increase in the luminescence lifetime ͑ϳ15% ͒. Results are discussed in terms of local density of optical modes surrounding a pointlike light emitter with important implications for the collection efficiency of luminescence and the estimation of internal quantum efficiency for a quantum dot.

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Luminescence of Individual Porous Si Chromophores

Cited by 130 publications

References 21 publications

Reactions and luminescence in passivated Si nanocrystallites induced by vacuum ultraviolet and soft-x-ray photons

Reactions and luminescence in passivated Si nanocrystallites induced by vacuum ultraviolet and soft-x-ray photons

Observation and control of blinking nitrogen-vacancy centres in discrete nanodiamonds

Effect of substrate proximity on luminescence yield from Si nanocrystals

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