Wyniki wyszukiwania - BazTech

1

Wide-angle infrared plasmonic perfect absorber based on graphene-silica grating

Chen Fang

Optica Applicata

|

2021

|

Vol. 51, nr 1

87--95

EN

In this paper, wide-angle infrared perfect absorption has been demonstrated by using a double-layer graphene strip grating coupled with a silicon dioxide grating. Numerical simulation of the finite-difference time-domain method indicates that the perfect absorption can be achieved due to the effective impedance matching, and all the incident electromagnetic energy is confined in the Al2O3 layer between the silver substrate and the graphene strip grating. Dual-band perfect absorption is achieved with the change of strip width or chemical potential of the bi-layer graphene strip grating. It is found that the spectral position of the absorption peak can be tuned by the chemical potential or the width of the graphene strip, and additionally by the size of the proposed absorber. Moreover, the proposed perfect absorber shows excellent absorption stability for a wide range of the incident angle up to ±65°. The proposed absorber may find potential application in tunable double band perfect absorbers in the mid-infrared range.

2

Synthesis and characterization of small size fluorescent LEEH caped blue emission ZnTe quantum dots

Patnaik S. K., Triapthy S. K., Sahu S. N.

Materials Science Poland

|

2017

|

Vol. 35, No. 1

1--5

EN

We report here for the first time the synthesis of LEEH caped very small size (2 nm) ZnTe quantum dots at low temperature (less than 100 °C) using a simple chemical route. The effects of aging and stirring time on the absorption spectra of the quantum dots were investigated. The synthesized nanocrystal (NC) was characterized by PL, TEM, XRD and the formation of very small size quantum dots having FCC structure was confirmed. Further, blue emission from the prepared sample was observed during exposure to monochromatic UV radiation. ZnTe NCs obtained in this study were found to be more stable compared to those presented in literature reports. ZnTe NCs may be considered as a new material in place of CdTe for optoelectronics devices.

3

Structural and luminescent properties of Fe3+ doped PVA capped CdTe nanoparticles

Ravindranadh K., Rao M. C.

Materials Science Poland

|

2017

|

Vol. 35, No. 2

390--397

EN

During recent decades, magnetic and semiconductor nanoparticles have attracted significant attention of scientists in various fields of engineering, physics, chemistry, biology and medicine. Fe3+ doped PVA capped CdTe nanoparticles were prepared by co-precipitation method and characterized by powder X-ray diffraction, SEM, TEM, FT-IR, optical, EPR and PL techniques to collect the information about the crystal structure, coordination/local site symmetry of doped Fe3+ ions in the host lattice and the luminescent properties of prepared sample. Powder XRD data revealed that the crystal structure belongs to a cubic system and its lattice cell parameters were evaluated. The average crystallite size was estimated to be 8 nm. The morphology of prepared samples was analyzed by using SEM and TEM investigations. Functional groups of the prepared sample were observed in FT-IR spectra. Optical absorption and EPR studies have shown that on doping, Fe3+ ions enter the host lattice in octahedral site symmetry. PL studies of Fe3+ doped PVA capped CdTe nanoparticles revealed UV and blue emission bands. CIE chromaticity coordinates were also calculated from the emission spectrum of Fe3+ doped PVA capped CdTe nanoparticles.

4

Characteristics of nanostructure dye-sensitized solar cells using food dyes

Hosseinnezhad M., Rouhani S.

Opto-Electronics Review

|

2016

|

Vol. 24, No. 1

34--39

EN

Dye-sensitized solar cells (DSSCs) were prepared using various food dyes. Food dyes are economically superior to organometallic dyes since they are nontoxic and inexpensive. The spectrophotometric evaluation of chosen food dyes in solution and on a TiO2 substrate show that the dyes form J-aggregation on the photoelectrode substrate. Oxidation of potential measurements for used food dyes ensured an energetically permissible and thermodynamically favorable charge transfer throughout the continuous cycle of a photo-electric conversion. The performance of dye-sensitized solar cells based on food dyes was studied. The results illustrate that the dye containing carboxylic acid and sulfonic acid as the acceptor group gave the maximum conversion efficiency 4.20%.

5

Stable phase CdS nanoparticles for optoelectronics: a study on surface morphology, structural and optical characterization

Kumar S., Sharma J. K.

Materials Science Poland

|

2016

|

Vol. 34, No. 2

368--373

EN

This work presents a study on the surface morphology, structure and optical behavior of stable phase cadmium sulphide (CdS) nanoparticles synthesized via co-precipitation technique. Scanning electron microscopy (SEM) analysis has been employed to study a cluster formation in the aggregated nanoparticles. An image analysis approach using ImageJ has been used to measure the size of nanoparticles from the SEM micrographs. Fourier transform infrared spectroscopic (FT-IR) analysis identified absorption peaks of Cd–S stretching along with moisture content. X-ray diffraction (XRD) analysis showed that CdS nanoparticles crystallized in wurtzite structure with a preferential orientation along (0 0 2) plane. The particle size, microstrain and lattice constants have been evaluated using XRD data. The lattice parameters of these nanoparticles were found to be shorter than the bulk value which led to lattice contraction. The optical absorption study showed a blue shift in the fundamental absorption edge indicating a quantum size effect.

6

Green to blue-green quartz from Rakowice Wielkie (Sudetes, south-western Poland) – a re-examination of prasiolite-related colour varieties of quartz

Platonov A. N., Szuszkiewicz A.

Mineralogia

|

2015

|

Vol. 46, iss. 1/2

1--12

EN

The green colour of prasiolite, defined as naturally occurring transparent macrocrystalline α-quartz with primary colouration, results from the optical absorption centred at ∼13,660 cm-1 and attributed to the FeVI2+→FeVI3+ intervalence charge transfer (Platonov et al. 1992). However, optical absorption spectroscopy of blue-green to green quartz from Rakowice Wielkie, Sudetes, south-western Poland, shows that its primary colouration results from the combination of this band and absorptions at ∼18,500 cm-1 and ∼16,250 cm-1. The first is assigned to a hole centre Fe4+s(Fe3+s-e- ) combined with an electron centre Fe2+I6(Fe3+I6+e- ), while the second from AlO4 4- defects. The quartz is blue-green if the 18,500 cm-1 prevails and becomes pale green if the 16,250 cm-1 band predominates. These colours seem to represent intermediate colour varieties between amethyst and prasiolite. We also suggest that spectral features of coloured quartz varieties might be useful indicators of changes in the physical- and chemical characteristics of the mineral-forming fluids.

7

Studies on Inx(As2Se3)1-x thin films using variable angle spectroscopic ellipsometry (VASE)

Amin G. A. M.

Materials Science Poland

|

2015

|

Vol. 33, No. 3

501--507

EN

The results of multi-angle ellipsometrical measurements of thermally evaporated In_x(AsSe₃)_1-x (x = 0, 0.01, 0.05) films are presented. Optical parameters n and Eg of thin In_x(AsSe₃)_1-x films show that indium atoms were incorporated into the host matrix of AsSe₃ forming distinct features depending on the indium concentration. Refractive index, n, was found to decrease with the addition of In to the binaryAsSe₃. The real and imaginary parts of the dielectric function, ε' and ε" were also calculated from the obtained data and correlated with In concentration. It was found that ε' decreases with the increaseof In content while ε" increases with the increase of In content. Absorption edge is shifted towards lower photon energy with the increase of In content. As a result, the optical energy gap decreases with increasing In content. This has been correlated with the chemical character of the additive as well as with the structural and bonding aspects of the amorphous composition. Nonlinear optical constants (Χ⁽³⁾ and n₂) were determined from linear optical parameters using semi-empirical relations in the long wavelength limit.

8

Optical spectroscopy of polyazomethine-PCBM nanostructures

Korona K. P., Grankowska S., Iwan A., Korona T., Rutkowska-Zbik D., Kamińska M.

Elektronika : konstrukcje, technologie, zastosowania

|

2014

|

Vol. 55, nr 9

92-94

EN

We report optical properties of a recently synthesized 25Th-cardo polyazomethine (PAZ) and of its mixture with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The polymer film had significant absorption for wavelengths shorter than 480 nm (2.6 eV). The external quantum efficiency of 25Thcardo: PCBM solar cell was the highest (about 0.3%) in the near UV range. Theoretical calculations show that HOMO energy levels are equal to –5.99 eV and –5.95 eV for PAZ and PCBM, respectively. Such a small energy difference enables hole leaking from PAZ to PCBM, what can explain low photo-current yield and presence of PCBM absorption bands in the photocurrent spectrum. Time-resolved photoluminescence revealed the emission band at 2.10 eV with a fast decay time of 7 ps, and the more stable band at 1.88 eV. It was observed that PCBM caused quenching of the PAZ emission, what indicates the energy transfer from PAZ to PCBM.

PL

W niniejszej pracy przedstawiamy właściwości optyczne otrzymanej poliazometiny 25Th-cardo i jej mieszaniny z estrem [6,6]-fenylo-metylowym-C61 kwasu masłowego (PCBM). Dla polimeru obserwujemy znaczącą absorpcję dla długości fal krótszych niż 480 nm (2,6 eV). Zewnętrzna wydajność kwantowa ogniw słonecznych na bazie 25Th-cardo:PCBM była najwyższa (około 0,3%) w zakresie bliskiego UV. Obliczenia teoretyczne pokazują, że energie poziomów HOMO są równe -6,0 eV i -5,99 eV, odpowiednio dla 25Th-cardo i PCBM. Tak mała różnica energii umożliwia wyciekanie dziur z 25Th-cardo do PCBM, co może tłumaczyć niską wydajność ogniw oraz obecność pasm absorpcyjnych PCBM w widmie fotoprądu. Fotoluminescencja czasowo-rozdzielcza daje pasmo emisji dla energii 2,10 Ev o szybkim czasie zaniku (7 ps) oraz bardziej stabilne pasmo przy 1,88 eV. Stwierdzono, że dodatek PCBM powoduje stłumienie emisji 25Th-cardo, co wskazuje na przenoszenie energii z 25Th-cardo do PCBM.

9

Synthesis and optical spectroscopy of the lithium tetraborate glasses, doped with terbium and dysprosium

Padlyak B., Ryba-Romanowski W., Lisiecki R., Pieprzyk B., Drzewiecki A., Adamiv V., Burak Y., Teslyuk I.

Optica Applicata

|

2012

|

Vol. 42, nr 2

365-379

EN

A series of the Tb- and Dy-doped glasses with Li2O-2B2O3 (or Li2B4O7:Tb and Li2B4O7:Dy) composition were synthesised and their spectroscopic properties were investigated. The Li2B4O7:Tb and Li2B4O7:Dy glasses of high chemical purity and optical quality were obtained from corresponding polycrystalline compounds in the air using standard glass technology. The Tb and Dy impurities were added to Li2B4O7 composition in the form of Tb2O3 and Dy2O3 oxide compounds in amounts of 0.5 and 1.0 mol%. The electron paramagnetic resonance (EPR), luminescence excitation and emission spectra of the Li2B4O7:Tb and Li2B4O7:Dy glasses were investigated. On the basis of EPR and photoluminescence spectra analysis it was shown that the Tb and Dy impurities are incorporated in the Li2B4O7 glass network as Tb3+ (4f8, 7F6) and Dy3+ (4f9, 6H15/2) ions, exclusively. All observed transitions of the Tb3+ and Dy3+ centres in the luminescence excitation and emission spectra were identified. The luminescence kinetics shows single exponential decay for Tb3+ and Dy3+ centres in Li2B4O7 glasses. The lifetime values for main emission transitions of the Tb3+ and Dy3+ centres in the Li2B4O7 glasses containing 0.5 and 1.0 mol% Tb2O3 and Dy2O3 are determined at T = 300 K. Peculiarities of optical properties and local structure of the Tb3+ and Dy3+ centres in the Li2B4O7:Tb and Li2B4O7:Dy glasses as well as their potential applications have been discussed.

10

Wpływ matrycy polimerowej na absorpcję optyczną i kinetykę fluorescencji kompozytów zawierających chromofory pochodnych pirazolochinoliny

Oźga K., Kuźnik W., Gondek E., Szota M., Dośpiał M., Nabiałek M., Czaja P.

Przetwórstwo Tworzyw

|

2011

|

[R.] 17, nr 6

479-482

PL

W pracy przedstawiono wyniki badań eksperymentalnych dla kompozytów, utworzonych w wyniku wbudowania nowych pochodnych chromoforów pirazolochinoliny (PQF) w matryce polimerowe różnego składu i różnej polarności. Ustalono wpływ polarności zastosowanych matryc polimerowych oraz stężenia chromoforów na zwiększenie wartości maksymalnego współczynnika absorpcji optycznej. Otrzymano zwężenie szerokości emisyjnej linii spektralnej o około 40 i 50 nm, w przypadku chromoforów pirazolochinoliny wbudowanych w bardziej polarne matryce polimerowe, takie jak polistyren (PS) czy poliwęglan (PC), w stosunku do matrycy poli(metakrylanu metylu) (PMMA). Fakt ten związany jest z oddziaływaniem dipol-dipol pomiędzy chromoforem PQF a zastosowaną matrycą polimerową. Dla chromoforów (o stężeniu optymalnym: 0,2 % w/w) wprowadzonych do matrycy PMMA z pomiarów zaniku fotoluminescencji wyznaczono czas relaksacji wynoszący 17,8 ns.

EN

This work covers experimental research on composites formed by incorporation of new chromophores - pyrazoloquinoline derivatives- into polymer matrices differing in composition and polarity. Influence of matrix polarity and chromophore concentration on maximum optical absorption coefficient was established. Emission spectral line narrowing by 40 to 50 nm was observed in the case of polystyrene (PS) and polycarbonate (PC) matrices with respect to poly(methyl methacrylate) (PMMA). This difference is attributed to dipole-dipole interactions between the PQF chromophore and the polymer matrix. Relaxation time of 17,8 ns was estimated from luminescence decay experiment for a composite containing 0,2 % w/w of chromophore in PMMA matrix.

11

Synthesis and optical spectroscopy of the Eu- and Pr-doped glasses with SrO–2B2O3 composition

Padlyak B., Grinberg M., Kuklinski B., Oseledchik Y., Smyrnov O., Kudryavtcev D., Prosvirnin A.

Optica Applicata

|

2010

|

Vol. 40, nr 2

413--426

EN

A series of Eu- and Pr-doped glasses with SrO–2B2O3 (or SrB4O7) composition were obtained and their spectroscopic properties were investigated. The SrB4O7 polycrystalline compounds were synthesised at T = 1300 K using high purity strontium carbonate (SrCO3) and boric acid (H3BO3). The Eu and Pr impurities were added to SrB4O7 compounds as Eu2O3 (amount: 0.167 at.%) and Pr2O3 (amounts: 0.05 and 0.25 at.%) oxides. The glass samples of high chemical purity and optical quality were obtained from corresponding polycrystalline compounds in the air atmosphere in platinum crucibles according to standard glass technology. Optical absorption, luminescence excitation and emission spectra of the Eu- and Pr-doped glasses with SrO–2B2O3 composition were investigated in the spectral range 300–800 nm at temperatures of 293 and 85 K. On the basis of optical spectra obtained and electron paramagnetic resonance (EPR) data analysis it is shown that Eu and Pr impurities are incorporated into the SrO–2B2O3 glass network as Eu3+ (4f6, 7F0) and Pr3+ (4f2, 3H4) ions, exclusively. All the observed transitions of the Eu3+ and Pr3+ centres in absorption and luminescence spectra were identified. The luminescence kinetics of Eu3+ and Pr3+ centres were investigated and analysed. The decay constants for main emission transitions in all samples investigated were obtained at room temperature. Peculiarities of incorporating the Eu3+ and Pr3+ activator ions in the glass with SrO–2B2O3 composition and their optical spectra are discussed in comparison with rare-earth doped polycrystalline compounds and single crystals with the same (SrB4O7) composition and other borate glasses.

12

Optical spectra and luminescence kinetics of the Sm3+ and Yb3+ centres in the lithium tetraborate glasses

Padlyak B., Ryba-Romanowski W., Lisiecki R., Adamiv V., Burak Y., Teslyuk I., Banaszak-Piechowska A.

Optica Applicata

|

2010

|

Vol. 40, nr 2

427--438

EN

Optical absorption, luminescence excitation, and emission spectra as well as luminescence kinetics of the Sm- and Yb-doped glasses with lithium tetraborate (Li2B4O7) composition were investigated and analysed. The Sm- and Yb-doped lithium tetraborate glasses of high optical quality were obtained in air from corresponding polycrystalline compounds according to standard glass synthesis technology. The Sm and Yb impurities were added to the Li2B4O7 compound in the form of Sm2O3 and Yb2O3 oxides in amount of 0.4 mol%. Using optical and electron paramagnetic resonance spectroscopy it was shown that the Sm and Yb impurities are incorporated into the lithium tetraborate glass network as Sm3+ (4f5, 6H5/2) and Yb3+ (4f13, 2F7/2) ions, exclusively. All of the observed transitions in the absorption and luminescence spectra of Sm3+ and Yb3+ centres were identified. The luminescence kinetics of the Sm3+ and Yb3+ centres in the Li2B4O7 glass are characterised by a single exponential decay. Decay constants for the main emission transitions of the Sm3+ and Yb3+ centres in the lithium tetraborate glass were obtained at T = 300 K. Incorporation peculiarities and optical spectra of Sm3+ and Yb3+ ions in the lithium tetraborate glass have been discussed in comparison with other borate glasses and crystals.

13

Optical properties of small silver particles embedded in soda-lime silica glasses

Suszyńska M., Morawska-Kowal T., Krajczyk L.

Optica Applicata

|

2010

|

Vol. 40, nr 2

397--401

EN

The optical characteristics of silver nanoparticles embedded in a surface layer of commercial soda lime silica glass have been analysed. Additional results were obtained by the transmission electron microscopy observations and the selective area electron diffraction patterns. In this report, we have shown the effect of deviation from the spherical shape and non-homogeneous distribution on the optical characteristics of the Ag nanocrystals embedded in the dielectric matrix under study.

14

Laser induced phenomena in .gamma.-glycine crystals

Wojciechowski A., Alzayed N., Kityk I., Berdowski J., Tylczyński Z.

Optica Applicata

|

2010

|

Vol. 40, nr 4

1007--1012

EN

The photoinduced changes of absorption within the spectral range 200-800 nm and optical second harmonic generation caused by illumination by the cw second harmonic generation of the Nd:YAG laser (? = 532 nm) and power about 400 mW were investigated. We have established that increasing the time of illumination by the second harmonic generation of the Nd:YAG laser leads to the occurrence of one strong spectral minimum at 319 nm and another less strong at 420 nm. Increasing the time of illumination leads to a slight red spectral shift of the photoinduced minima. The absence of a substantial increase in temperature indicates that the principal role is played here by the photooccupation of the trapping levels. The effect is observed in a wide spectral range of the incident photoinduced angles, however, the beam should possess a good Gaussian-like form and to be space homogenous. The results were reproduced with precision up to 3-4% which was achieved due to additional stabilization of the photoinduced laser power by double control of the power.

15

Dosimetric properties of gammaand electron-irradiated commercial window glasses

Fuochi P., Corda U., Lavalle M., Kovács A., Baranyai M., Mejri A., Farah K.

Nukleonika

|

2009

|

Vol. 54, No. 1

39-43

EN

Two different types of window glasses have been investigated as possible routine dosimeters in the range of 1-50 kGy. Glass samples were irradiated with 3.4 MeV and 8.4 MeV electron beams and the results compared with those obtained by 60Co gamma irradiation. Due to the strong optical absorption at wavelengths ess than 310 nm, even at low doses, optical measurements were limited to the range 320-700 nm. In both types of glasses, irradiation induced two absorption bands around 410 and 600 nm the intensities of which are proportional to dose; the 600 nm band being less sensitive to radiation. These bands have been attributed to non bridging oxygen hole centres existing in two different configurations. Because of the rapid fading of the optical absorbance observed at room temperature immediately after irradiation (greater than 15% in two days), the samples underwent a post-irradiation thermal treatment (150 graduate C for 20 min) to improve the stability of absorbance. The fading characteristics of the irradiated and thermally treated glasses, kept in the dark at room temperature, were studied for several weeks. A fast decay, whose intensity depends on the type and energy of the ionizing radiation, was observed for few days after irradiation and thermal treatment, followed by a much slower decay. The results show that this kind of material could be used as routine dosimeters within a certain dose range, as long as proper calibrations are made for each batch of glass and the appropriate precautions are taken when doing calibration and performing routine dosimetry.

16

Optical spectroscopy and local structure of the Nd3+ luminescence centres in glasses of the CaO-Ga2O3-GeO2 system

Padlyak B., Ryba-Romanowski W., Lisiecki R.

Optica Applicata

|

2008

|

Vol. 38, nr 1

189-202

EN

Optical absorption and luminescence spectra as well as luminescence kinetics of the Nd3+ centres in glasses with Ca3Ga2Ge3O12:Nd composition, containing 0.2 and 1.0 wt% of the Nd2O3 were presented and analysed. The oscillator strengths and phenomenological intensity parameters omega t (omega 2, omega 4, and omega 6) were obtained using standard Judd-Ofelt theory. Calculated omega t parameters, radiative transitions rates, branching ratios and radiative lifetime for Nd3+ centres in the glass with Ca3Ga2Ge3O12 composition were analysed and compared with corresponding Nd3+ parameters in their crystalline analogue with garnet structure. Experimental lifetimes are compared with those calculated, and quantum efficiency of Nd3+ centres from 4F3/2 emitting level in the glass with Ca3Ga2Ge3O12 composition is estimated. Incorporation peculiarities and local structure of Nd3+ luminescence centres in the glass with Ca3Ga2Ge3O12 composition and corresponding Ca3Ga2Ge3O12:Nd3+ garnet laser crystals are considered. On the basis of extended X-ray absorption fine structure (EXAFS) spectra (L3-edge) of rare-earth elements analysis it has been shown that Nd3+ luminescence centres in the CaO-Ga2O3-GeO2 glass network occupy structural sites with the coordination number to oxygen N = 6.

17

Influence of nickel ions on dielectric and other physical properties of PbO-MoO3-B2O3 glass system

Prasad P.S., Kumar V.R., Raju G.N., Veeraiah N.

Materials Science Poland

|

2008

|

Vol. 26, No. 3

527--545

EN

PbO–MoO3–B2O3 glasses containing various proportions of NiO (ranging from 0 to 1.0 mol %) have been prepared. A number of methods viz., differential thermal analysis, spectroscopic (IR and UV-Vis optical absorption, and ESR spectra) and dielectric properties (ĺ', tanä, a.c. conductivity óac over a range of frequencies and temperatures) of these glasses has been employed in studies. The results of differential thermal analysis suggest a high glass forming ability for the glass containing 0.6 mol % of NiO. The studies of UV-Vis and IR spectra show that nickel ions occupy both tetrahedral and octahedral positions in the glass network with the dominance of the tetrahedral positions when the concentration of NiO is below 0.6 mol % in the glass matrix. The analysis of the results of studies of dielectric properties reveals that there is an increase in the rigidity and the dielectric breakdown strength of the glass when the concentration of NiO is around 0.6 mol %.

18

Photochromic effects in sillenite single crystals

Żmija J., Małachowski M.

Archives of Materials Science and Engineering

|

2008

|

Vol. 33, nr 2

101-106

EN

Purpose: The aim of this work was to fabricate the doped with transition or rare earth metals the single crystals such as Bi12GeO20 (BGO) and Bi12SiO20 (BSO), showing the photochromic effect and to study this effect. Findings: To the study results we can count the development of the mentioned single crystal technology and the measurement set as well as the interpretation of the obtained absorption spectra. Research limitations/implications: Among others we have found that the photochromic effect in these materials is connected with the change in doped atom charge state by one electron ie. Mn+4 → Mn+5 and Cr+3 → Cr+4. We also propose the schematic presentation of the energetic levels obtained on the basis of the above remarks. Originality/value: The authors show, for the first time, the photochromic effect in doped with transition or rare earth metals the BGO and BSO single crystals and developed the model explaining this effect. The similar studies were performed on the BTMO (T=Ti, M=Pb) mixed crystals. The applications are connected with the areas of scientific studies of some single crystals as well as using them in particular devices.

19

Spectroscopic studies of the copper-cadmium halide photochromic glasses

Marczuk K., Mirowska N.

Optica Applicata

|

2005

|

Vol. 35, nr 4

859-867

EN

The spectra of optical absorption, luminescence excitation and photoluminescence in the range of 200-750 nm in the Cu-Cd-photochromic glasses were measured. As a matrix of photochromic glass the sodium-borosilicate glass was used. The absorption within the UV wavelength range (200-300 nm) is connected to various structural defects of the matrix glass. The changes of the optical absorption and photoluminescence excitations resulting from the UV radiation in the Cu-Cd-photochromic glasses have been analysed. It was noticed the share of the matrix glass structure components in creation of the colour centers stable of room temperature.

20

Spectroscopic and dielectric characteristics of nickel-doped porous silica glasses

Macalik B., Suszyńska M., Rysiakiewicz-Pasek E., Krawczyk L., Morawska-Kowal T., Okal J.

Optica Applicata

|

2005

|

Vol. 35, nr 4

761-767

EN

The direct current conduction and electrical relaxation currents in nickel-doped porous silica glasses were investigated by using the thermally stimulated polarisation and depolarisation current techniques in a wide temperature range. Optical absorption measurements and transmission electron microscopy observations accompanied these studies. All characteristics were found to be affected by the porous matrix and the material filling the pores.