Possibilities for study of porous systems and some defective materials by positron annihilation spectroscopy

Prokop’ev, E. P.; Grafutin, V. I.; Тимошенков, С. П.; Funtikov, Yu. V.

doi:10.1134/s1061830908100070

Cited by 2 publications

(7 citation statements)

References 8 publications

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“…From this formula for a positron where m þ * % m 0 then v % 1.06 · 10 7 cm/s, and for a p À Ps where m þ * % 2m 0 then v % 7.52 · 10 6 cm/s. From this it appears that at z (R, T) % 1 then equation (5) gives N d ¼ k tr /s Ps % 1.27 · 10 14 cm À3 .…”

Section: Definition Of Radii Of Pores and Their Concentration In Poromentioning

confidence: 87%

“…In this formula t b % 0.22 ns [32] is meaningful for the lifetime of the positron or t b ¼ 0.5 ns -the average on the spin positronium lifetime in the environment volume (outside of pore or vacancy) [5,[18][19][20][21][22][23].…”

Section: The Sizes Of Free Volumes Pores and Holes In Porous Systemmentioning

confidence: 99%

“…Positron annihilation spectroscopy (PAS) [1][2][3][4][5][6][7], can be used to study the electronic structure of perfect crystals and imperfections, such as vacancies and free volumes in solids and porous systems respectively. The technique can be thought of in terms of three basic approaches: to study of the time distribution of annihilation photons (TDAP), the angular distribution of annihilation photons (ADAP), and the Doppler broadening of annihilation lines (DBAL) with an energy of 0.511 MeV [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…The following points can be drawn from a study of the literature on the application of PAS to nanocrystals of metals and alloys [2][3][4][5][6][7][8], semiconductors [9][10][11][12][13][14][15][16], and porous silicon and polymers [5,17,29].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Positronics and nanotechnologies: Possibilities of studying nano-objects in technically important materials and nanomaterials

Chaplygin

Гаврилов

Grafutin

et al. 2007

Proceedings of the Institution of Mechanical Engineers, Part N:

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This article shows that an effective method to define the size of nano-objects (vacancies, vacancy, clusters, free pore volumes, cavities, and holes), and their concentration and chemical composition, is positron annihilation spectroscopy (PAS). A review of the state of the art of the application of the PAS technique to probe nanostructures in porous silicon, silicon and single crystal quartz samples is presented.

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Section: Definition Of Radii Of Pores and Their Concentration In Poromentioning

confidence: 87%

Section: The Sizes Of Free Volumes Pores and Holes In Porous Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Positronics and nanotechnologies: Possibilities of studying nano-objects in technically important materials and nanomaterials

Chaplygin

Гаврилов

Grafutin

et al. 2007

Proceedings of the Institution of Mechanical Engineers, Part N:

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“…This technique based on positron annihilation lifetime (PAL) spectroscopy is a highly suitable method for thorough investigation of nanopores and mesopores. The PAL spectroscopy is a non-destructive technique, which uses the positronium (electron-positron bound state) as a probe for porosity investigation [2]. The lifetime of positronium allows us to evaluate the pore size and the positronium yield can be used to monitor changes in pore concentration.…”

Section: Introductionmentioning

confidence: 99%

Positron Lifetime Spectroscopy of Silicon Nanocontainers for Cancer Theranostic Applications

Akmalova¹,

Dubov²,

Степанов³

et al. 2018

KEn

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Biocompatibility and biodegradability of porous silicon (por-Si) nanoparticles (NPs), as well as the fact that they can selectively accumulate in tumor tissues, allow using them as containers for delivery of diagnostic markers or drugs for therapy of cancer tumors. Advantages of por-Si NPs as carriers of drugs are also favorable due to the high surface area and large pore volume. To apply por-Si NPs as nanocontainers it is necessary to have the comprehensive information about their porosity. In our work we use the positron annihilation lifetime (PAL) spectroscopy for porosity investigation. Samples of por-Si were prepared by electrochemical etching of heavily boron doped crystalline Si wafers in a hydrofluoric acid solution. The prepared por-Si films were dried and mechanically milled to obtain powder of NPs, which was pressed into tablets for PAL investigation. Ortho-positronium components of the measured positron lifetime spectra allowed us to evaluate the pore size distribution in por-Si NPs as continuous bimodal one with two peaks near 1 nm and 3 nm.

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Possibilities for study of porous systems and some defective materials by positron annihilation spectroscopy

Cited by 2 publications

References 8 publications

Positronics and nanotechnologies: Possibilities of studying nano-objects in technically important materials and nanomaterials

Positronics and nanotechnologies: Possibilities of studying nano-objects in technically important materials and nanomaterials

Positron Lifetime Spectroscopy of Silicon Nanocontainers for Cancer Theranostic Applications

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