Proton gated emission from porous silicon

Chun, Jonathan K.M.; Bocarsly, Andrew Bruce; Cottrell, T. R.; Benziger, J.; Yee, J. C.

doi:10.1021/ja00060a080

Cited by 56 publications

(64 citation statements)

References 3 publications

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“…15 Bocarsly and co-workers found that Brønsted bases such as Na 2 CO 3 and NaOH reversibly quench the PL from p-Si and that the PL is restored by subsequent exposure to Brønsted acids. [16][17][18] They explained the quenching process in terms of a proton-transfer abstraction mechanism. Coffer and co-workers investigated both steric and electronic effects in the PL quenching of p-Si by Lewis bases such as alkylamines and compared the PL quenching from p-Si and Si nanocrystals.…”

Section: Introductionmentioning

confidence: 99%

Decay Dynamics and Quenching of Photoluminescence from Silicon Nanocrystals by Aromatic Nitro Compounds

Germanenko

El‐Shall

2000

J. Phys. Chem. B

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The decay dynamics and the quenching of the photoluminescence (PL) from Si nanocrystals are investigated. Electron acceptors whose reduction potentials lie below the conduction band (CB) edge of the Si nanocrystals quench the red emission from the Si nanocrystals. The quenching rate constants obtained from Stern-Volmer analyses for 3,5-dinitrobenzonitrile, 4-nitrophthalonitrile, 1,4-dinitrobenzene, 4-nitrobenzonitrile, 2,3-dinitrotoluene, 3,4-dinitrotoluene, 2,4-dinitrotoluene, and 2,6-dinitrotoluene are in the range of 10 6 -10 7 M -1 s -1 . The quenching mechanism occurs via an electron transfer from the CB band of the Si nanocrystals to the vacant orbitals of the quenchers. The PL decay profiles of the Si nanocrystals, in the presence and absence of the quencher, are well described by the stretched exponential decay law. The band gap of the Si nanocrystals estimated from the present study is larger than the PL peak energy. The results are consistent with a quantumconfinement model, where recombination of electrons and holes occurs in a surface state. The ability of nitrotoluenes to quench the PL from Si nanocrystals could be used to develop a sensor based on Si nanostructures for the detection of explosives. IntroductionSilicon nanostructures have stimulated much interest because of their unique properties such as single-electron tunneling, nonlinear optical properties, and visible photoluminescence (PL). 1-7 Studies of Si nanostructures have grown extensively since the discovery of efficient PL from porous Si (p-Si) with the ultimate goals of achieving a complete fundamental understanding of the phenomenon as well as developing potential display devices and chemical-sensor applications. 1-10 Si nanocrystals have optical and PL properties very similar to those of p-Si, and it is generally accepted that they are the emitting chromophores in p-Si. Kinetic quantum confinement appears to be the most reliable model to explain the origin and properties of the PL from Si nanocrystals. The higher energy shift in the PL of Si nanocrystals is attributed to the three-dimensional quantum size effect. The nonradiative recombination process is decreased significantly in the nanocrystal as the electronhole pairs in separate nanocrystals are electrically isolated. However, in both p-Si and Si nanocrystals, the PL properties are related not only to the respective nanocrystalline size but also to the structure and properties of the surrounding medium. The study of these effects is essential for utilizing Si nanostructures in potential device applications.Many organic and inorganic molecules have been shown to efficiently quench the PL from p-Si, and both energy-and electron-transfer mechanisms have been proposed to explain this PL quenching. 11-30 Sailor and co-workers found a number of polar solvent molecules that reversibly quenched the PL from p-Si. 11-15 They also studied the quenching by aromatic molecules and concluded that energy transfer from the p-Si excited state to the triplet levels of the quencher molecules predomi...

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Section: Introductionmentioning

confidence: 99%

Decay Dynamics and Quenching of Photoluminescence from Silicon Nanocrystals by Aromatic Nitro Compounds

Germanenko

El‐Shall

2000

J. Phys. Chem. B

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“…For instance, CdS and Cd 3 As 2 display dramatic increases in emission intensity, up to 4-fold, in the presence of alkylamines (14), and CdS particles are quenched by benzyl alcohol (15). The emission of porous silicon, thought to be partially composed of Si nanoparticles, can be quenched by oxygen-containing solvents and amines (16 -18), and porous silicon can display pH-dependent intensities (19). These properties are analogous to fluorescent sensors for which the emission intensity, wavelength, or lifetime is sensitive to the presence of analytes such as H ϩ , Ca 2ϩ , Cl Ϫ , or oxygen (20,21).…”

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confidence: 99%

Time-Resolved Spectral Observations of Cadmium-Enriched Cadmium Sulfide Nanoparticles and the Effects of DNA Oligomer Binding

Lakowicz

Gryczyński

et al. 2000

Analytical Biochemistry

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We measured the steady-state and time-resolved fluorescence spectral properties of cadmium-enriched nanoparticles (CdS-Cd2+). These particles displayed two emission maxima, at 460 and 580 nm. The emission spectra were independent of excitation wavelength. Surprisingly, the intensity decays were strongly dependent on the observation wavelength, with longer decay times being observed at longer wavelengths. The mean lifetime increased from 150 to 370 ns as the emission wavelength was increased from 460 to 650 nm. The wavelength-dependent lifetimes were used to construct the time-resolved emission spectra, which showed a growth of the long-wavelength emission at longer times, and decay-associated spectra, which showed the longer wavelength emission associated with the longer decay time. These nanoparticles displayed anisotropy values as high as 0.35, depending on the excitation and emission wavelengths. Such high anisotropies are unexpected for presumably spherical nanoparticles. The anisotropy decayed with two correlation times near 5 and 370 ns, with the larger value probably due to overall rotational diffusion of the nanoparticles. Addition of a 32-base pair oligomer selectively quenched the 460-nm emission, with less quenching being observed at longer wavelengths. The time-resolved intensity decays were minimally affected by the DNA, suggesting a static quenching mechanism. The wavelength-selected quenching shown by the nanoparticles may make them useful for DNA analysis.

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“…However, the as-produced nanoparticles do not disperse well in most common organic solvents, which is a necessary step in the processing of these polymer films. Further, the PL of unprotected nanocrystalline silicon has been shown by many authors to be severely quenched by the presence of various chemical species, including many amines [10][11][12]. We have observed such quenching due to the presence of the PVK polymer.…”

Section: Resultsmentioning

confidence: 51%

Optical Properties of Polymer-Embedded Silicon Nanoparticles

Kirkey

Cartwright

et al. 2003

MRS Proc.

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We seek to use electrically conducting polymers, such as those commonly utilized in polymeric LEDs, as hosts for silicon nanoparticles. The proper design of multilayered devices based on these materials will yield efficient light-emitters in which charge carriers localize and recombine within the nanoparticles. Furthermore, these may combine the flexibility and processability of polymeric LEDs with the reliability of inorganic materials. We have synthesized luminescent silicon nanoparticles and have characterized their photoluminescence (PL) using continuous-wave and time-resolved spectroscopy. These particles have been incorporated into a variety of transparent solid hosts. The photoluminescence obtained from particle-containing poly(methyl methacrylate) (PMMA) matrices is very similar to that of the particles in solution, both in spectral content and PL decay characteristics. However, when incorporated into a variety of conducting polymers, such as poly(N-vinylcarbazole) (PVK), the nanoparticles do not retain their photoluminescence properties. A variety of chemical species have been reported as effective PL quenchers for porous silicon. We believe that these polymers quench the luminescence through similar mechanisms. Protective passivation of the nanoparticle surface is suggested as a strategy for overcoming this quenching.

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Proton gated emission from porous silicon

Cited by 56 publications

References 3 publications

Decay Dynamics and Quenching of Photoluminescence from Silicon Nanocrystals by Aromatic Nitro Compounds

Decay Dynamics and Quenching of Photoluminescence from Silicon Nanocrystals by Aromatic Nitro Compounds

Time-Resolved Spectral Observations of Cadmium-Enriched Cadmium Sulfide Nanoparticles and the Effects of DNA Oligomer Binding

Optical Properties of Polymer-Embedded Silicon Nanoparticles

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