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1
Content available remote Photoluminescence features of AgBr nanoparticles formed in porous glass matrices
Doycho I. K., Gevelyuk S. A., Ptashchenko O. O., Rysiakiewicz-Pasek E., Tolmachova T. M., Tyurin O. V., Zhukov S. O.
Optica Applicata
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2010
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Vol. 40, nr 2
323--332
EN
The photoluminescence of AgBr nanoparticles formed by a two stage liquid-gas microsynthesis technology in two types of porous glass with different sizes of pores was investigated. Polyvinyl alcohol (Polinol) was used as a binder. It has been found that AgBr nanoparticles in the glasses with smaller pores luminesce more intensively, and we attribute this phenomenon to the differ-ences in pore size distributions. The luminescence spectra were shown to have two maxima corresponding to AgBr nanoparticles formed within the nanopores of two different sizes characteristic of each of the matrices. In both cases, the spectra excited by xenon lamp irradiation are more intensive than those stimulated by a 337-nm nitrogen laser. Comparing the maxima shifts in the phosphorescence excitation spectra with ones in phosphorescence spectra we can conclude that the luminescence and phosphorescence centers in AgBr nanoparticles are of identical nature in the matrices of both types. The investigation results fit neatly into the inherently consistent quantum confinement model and are well correlated with the poroscopic spectra of both types of glass.
2
Content available remote Aggregation of dyes in porous glass
Tyurin O. V., Bercov Y. M., Zhukov S. O., Levitskaya T. F., Gevelyuk S. A., Doycho I. K., Rysiakiewicz-Pasek E.
Optica Applicata
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2010
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Vol. 40, nr 2
311--321
EN
The research examines the interaction of dye molecules with their dimers (H aggregates) and the more complex formations (J aggregates) developing in porous glass. The use of porous glass when dealing with dye aggregation has resulted in obtaining photoluminescence dimers of the J aggregating dye, the formation of which is difficult under normal conditions. In addition, the porous glass matrix contributes to a substantial reduction in the interaction of photoexcited states of both a molecular and an aggregated dye, thus helping maximize the luminescence efficiency of porous glass-distributed dyes.
3
Content available remote The photoluminescent properties of CdS clusters of different size in porous glasses
Rysiakiewicz-Pasek E., Polańska J., Gevelyuk S.A., Doycho I.K., Mak V.T., Zhukov S.A.
Optica Applicata
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2008
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Vol. 38, nr 1
93-100
EN
CdS nanoclusters were formed in the porous glass matrix by sequential chemical deposition from liquid-vapor phase and their chemical content was investigated. The room temperature photoluminescence spectra of specimens excited with a 235 nm wavelength had typical narrow peaks at 400 nm. The peaks can be explained by quantum effects for charge carriers confined inside the small-size (radius of the order of several nanometers) clusters. At the same time the luminescence spectra of the same specimens, but excited with a xenon lamp at 77 K, had peaks at ~700 nm that approximately corresponded to the band gap of the crystalline CdS. The possibility of the crystallites existence follows from the size distribution of voids in the porous glass matrix and is confirmed by the X-ray spectra typical of the wurtzite structure. The peculiarities of the observed luminescence spectra are explained by the energetic diagram of CdS in the configurational space.
4
Content available remote Small doses γ-irradiation effect on the photoluminescence properties of porous glasses
Doycho I. K., Gevelyuk S. A., Kovalenko M. P., Prokopovich L. P., Rysiakiewicz-Pasek E.
Optica Applicata
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2003
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Vol. 33, nr 1
55-65
EN
The g-irradiation effect on the photoluminescence of various types of porous silica glasses and on its change during a half-year storage has been studied. It has been revealed that the photoluminescence intensity of glasses with fine matrix and almost complete absence of silica gel does not change when irradiated at applied doses, but a long-wave shift of its maximum position is observed. The increase in photoluminescence intensity appeared to be the most stable in glasses with the thick-wall matrix. The model which explains apparent changes in photo-luminescent properties and also allows us to draw conclusions about some features of various types of porous silicate glasses structure has been presented.
5
Content available remote Effect of antibiotic insertion on photoluminescent properties of silicate porous glasses used in ophthalmologic prostheses
Rysiakiewicz-Pasek E., Gevelyuk S. A., Doycho I. K., Prokopovich L. P., Safronsky E. D.
Optica Applicata
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2003
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Vol. 33, nr 1
33-39
EN
The selection of silica porous glass being the most suitable material for manufacturing of the actuated scleral part of the eye prosthesis has been justified. The model explaining the photoluminescence intensity oscillations of porous glass during the effusion of the antibiotic out of the glass has been proposed. Multiple usage of the antibiotic has been found to lead to the etching effect of the porous glass and a method of minimization of the effect has been presented.
6
Content available remote Linear extension of porous glasses with modified internal surface in humid environment.
Gevelyuk S. A., Doycho I. K., Lishchuk D. E., Prokopovich L. P., Safronsky E. D., Rysiakiewicz-Pasek E., Roizin Y. O.
Optica Applicata
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2000
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Vol. 30, nr 4
605-611
EN
An original interferometric technique for investigating the influence of humidity on change in the linear dimensions of porous silica glasses is developed. The linear dimensions of a specimen are shown to change as a result of competition in the system of compressive capillary forces and expansion forces arising from the swelling of the residual silica gel present in pores. The possibility of selective inhibition of the capillary squeezing forces or the silica gel expansion forces by the pre-treatment of a porous material by a hydrophobized composition (hexamethyldisilazan - HMDS) or by annealing of carbon impregnated inside of the pores is shown experimentally.
7
Content available remote Influence of gamma -irradiation on the photoluminescent properties of porous glasses.
Gevelyuk S.A., Lishchuk D.E., Mak V.T., Rysiakiewicz-Pasek E., Marczuk K.
Optica Applicata
|
2000
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Vol. 30, nr 4
595-603
EN
The influence of small doses of gamma -irradiation on the features of the photoluminescence spectra of porous silica glass during long-time (several months) storage after the irradiation is investigated. The non-monotonic dependence of photoluminescence change on the dose of the glasses with a different composition and different additional pre-treatment is observed. The analysis of intensity changes and shifts of the maxims of the photoluminescence spectra shows long-time oscillations. This indicates that the composite catalytic processes take place on the surface of the pores. Perhaps the small gamma -radiation doses initiate the cyclic process of the surface state transformation on the inner side of the pores.
8
Content available remote Carbon treatment as a method of the surface development of porous glasses
Gevelyuk S.A., Doycho I.K., Kovalenko M.P., Safronsky E.D., Rysiakiewicz-Pasek E., Roizin Y.O.
Optica Applicata
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2000
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Vol. 30, nr 4
635-640
EN
A method to develop the structure of the internal pore surface is proposed. The surface of porous silicate glasses is modified by impregnating carbon into the pores and subsequent annealing. The procedure is repeated several times. A technique to control the properties of the pore surface is proposed as well. Analysing the change in the features of the photoluminescence spectrum as a result of such treatment in comparison with the pore-size distribution spectra allows us to assume formation of silicon nanoclusters in porous glass and to estimate their sizes. The nonmonotonic change of the surface development with simultaneous stationary increase of photoluminescence intensity is explained by the composite pattern of the silicon clusters change during multiple carbon treatments.
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