Alla B. Chebotareva - Academia.edu (original) (raw)

Papers by Alla B. Chebotareva

Research paper thumbnail of The Effect of Local Doping of the Polymer–Polymer Interface Using Cu2O Particles

Applied Sciences

Electrically conductive polymer materials are increasingly being used as electronic materials, fo... more Electrically conductive polymer materials are increasingly being used as electronic materials, for example, in thin-film transistors. However, the low mobility of charge carriers limits their use. One of the ways to increase the mobility of charge carriers can be the use of interface conductivity along the regions separating the two polymer films. It is important that it could be realized with non-conjugated polymers. There is no direct experimental evidence that the transport of charge carriers occurs along such an interface. It is impossible to deny the possibility of transport on the surfaces of polymer films. The purpose of this work is to study the current flow path in a multilayer sample by marking the polymer–polymer interface with a doping nanolayer of a Cu2O island film. Spectral methods in the field of electronic absorption of copper oxide were used to control the island film. The electronic parameters of the polymer–polymer interface were studied using injection methods a...

Research paper thumbnail of Non-Conjugated Copoly(Arylene Ether Ketone) for the Current-Collecting System of a Solar Cell with Indium Tin Oxide Electrode

Polymers, Feb 13, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Formation of low-reflection multicrystalline silicon surface by laser-induced structuring for application on silicon solar cells

SPIE Proceedings, 2010

The formation of laser-induced structures on the multicrystalline silicon surface has been invest... more The formation of laser-induced structures on the multicrystalline silicon surface has been investigated. Optimum performances of the surface structurization have been explored. A cardinal decrease in reflectance from modified surface has been discovered in a wide spectral range in comparison with the samples of chemically texturized monocrystalline silicon. The influence of subsequent chemical etching on the reflection spectra of the

Research paper thumbnail of Contact resistance of indium tin oxide and fluorine-doped indium oxide films grown by ultrasonic spray pyrolysis to diffusion layers in silicon solar cells

Solar Energy Materials and Solar Cells, 2015

A simple method is described for estimating the contact resistance between a transparent conducti... more A simple method is described for estimating the contact resistance between a transparent conducting oxide film and a diffusion layer in a silicon solar cell. We have investigated the effect of film growth temperature on the contact resistance between n þ þ-Si and p þ þ-Si layers and In 2 O 3 :Sn (ITO) and In 2 O 3 : F (IFO) films grown by ultrasonic spray pyrolysis. The effect of growth temperature on the properties of the SiO x layer in IFO/SiO x /n þ þ-Si structures has been studied by Fourier transform infrared absorption spectroscopy. The process for IFO deposition on n þ þ-Si layers has been modified in order to reduce the IFO/SiO x /n þ þ-Si contact resistance. The use of modified IFO has reduced the series resistance of an ITO/ (p þ þ nn þ þ)Cz-Si/IFO bifacial solar cell for low-concentration applications by 0.13 Ω cm 2 , from 0.39 to 0.26 Ω cm 2 ; extended its operating range of concentration ratios by a factor of 1.5, from 1-3.5 Â to 1-5.3 Â ; and improved its efficiency in the operating range from 17.6-17.9 to 17.7-18.2%.

Research paper thumbnail of Crystalline silicon solar cells with laser ablated penetrating V-grooves: Modeling and experiment

physica status solidi (a), 2012

Different approaches are under elaboration aimed at the cost reduction of solar electricity. 3D p... more Different approaches are under elaboration aimed at the cost reduction of solar electricity. 3D penetrating emitter solar cells are expected to offer performance enhancement at lower costs, using low carrier lifetime cheaper silicon. Using laser ablation, we have prepared indium-fluorine-oxide/(n þ pp þ)Cz-Si/ indium-tin-oxide bifacial silicon solar cells with deep (110-120 mm) penetrating V-shaped emitter with aspect ratio of 3-4 (height to half-width of the V-grooves). Compared with the reference cell textured with conventional random pyramids and thus not damaged by laser action, which showed front/rear active area photocurrents of 41.1/33.3 mA cm À2 , V-grooved solar cells showed only slightly less front photocurrent of 40.1-40.7 mA cm À2 , whereas the superior rear photocurrent of 34.2 mA cm À2. The latter indicates that deep penetrating emitter is especially useful in the case of bifacial solar cells. The best pseudo-efficiency for V-grooved cell of 19.5% with estimated bifaciality of $80% was obtained for the cell that has been subjected to the smallest laser action during Vgrooving. In addition, ray-tracing model was applied to calculate efficiency of light absorption by a V-grooved silicon solar cell for wavelengths in the range from 400 to 1200 nm. The depth of the grooves was varied from 0.05t to wafer's thickness t. The obtained experimental and computational results confirm that the design of crystalline silicon solar cell based on deep penetrating V-shaped emitter makes possible to obtain high-efficiency solar cells even in the case of low-quality silicon wafers. Silicon wafer with deep penetrating V-grooved emitter.

Research paper thumbnail of Bifacial low concentrator argentum free crystalline silicon solar cells based on ARC of TCO and current collecting grid of copper wire

AIP Conference Proceedings, 2013

Results obtained in frame of an innovative approach for fabrication of the bifacial low concentra... more Results obtained in frame of an innovative approach for fabrication of the bifacial low concentrator Ag free Cz silicon solar cells based on Indium-Tin-Oxide(ITO)/(p + nn +)Cz-Si/Indium-Fluorine-Oxide (IFO) structure (n-type cell) as well as on IFO/(n + pp +)Cz-Si/ITO structure (p-type cell) are presented in this work. The (p + nn +)Cz-Si and (n + pp +)Cz-Si structures were produced by diffusion of boron and phosphorus from deposited Band P-containing glasses followed by an etch-back step. The n + surface of the structures was textured, whereas the p + surface remained planar. Transparent conducting oxide (TCO) films, which act as passivating and antireflection electrodes, were deposited by ultrasonic spray pyrolysis method on both sides. The contact pattern of copper wire was attached by the lowtemperature (160 °C) lamination method simultaneously to the front and rear TCO layers as well as to the interconnecting ribbons arranged outside the structure. The shadowing from the contacts is in the range of ~4%. The resulting solar cells showed front/rear efficiencies of 18.6-19.0%/14.9-15.3% (p-type cell) and 17.5-17.9%/16.5-17.0% (n-type cell) respectively at 1-5 suns. Even for 1 sun illumination at 20-50% albedo, similar energy production corresponds to 21.6-26.1% (p-type cell) and 20.8-25.8% (n-type cell) efficiency of a monofacial cell.

Research paper thumbnail of Fluorine doped indium oxide films for silicon solar cells

Thin Solid Films, 2009

The effect of conditions of preparation of the In 2 O 3 :F(IFO)/(pp +)Si solar cell (SC) by pyros... more The effect of conditions of preparation of the In 2 O 3 :F(IFO)/(pp +)Si solar cell (SC) by pyrosol method was systematically studied with the goal to maximize its photovoltage. Heterojunction IFO/(pp +)Si SC was obtained with the efficiency of 16.6% and photovoltage of 617 mV as well as the IFO/(n + pp +)Si SC with the efficiency of 19.2% using the following obtained optimal conditions: film-forming solution: 0.2 M InCl 3 +0.05 M NH 4 F+0.1 M H 2 O in methanol; carrier gas-Ar+ 5% O 2 ; deposition temperature-480°C; duration of deposition-2 min; two-minute annealing in argon with sprayed methanol at a temperature of 380°C.

Research paper thumbnail of Concentrator bifacial Ag-free LGCells

Solar Energy, 2014

ABSTRACT Results obtained for the bifacial low concentrator Ag free Cz silicon solar cells based ... more ABSTRACT Results obtained for the bifacial low concentrator Ag free Cz silicon solar cells based on Indium–Tin–Oxide(ITO)/(p+nn+)Cz–Si/Indium–Fluorine–Oxide (IFO) structure (“n-type” cell) as well as on IFO/(n+pp+)Cz–Si/ITO structure (“p-type” cell) are presented in this work. The (p+nn+)Cz–Si and (n+pp+)Cz–Si structures were produced by diffusion of boron and phosphorus from deposited B- and P-containing glasses followed by an etch-back step. The n+ surface of the structures was textured, whereas the p+ surface remained planar. Transparent Conducting Oxide (TCO) films, which act as antireflection electrodes, were deposited by ultrasonic spray pyrolysis method on both sides. The contact pattern of copper wire was attached by the low-temperature (160 °C) lamination method simultaneously to the front and rear TCO layers as well as to the interconnecting ribbons arranged outside the structure. The shadowing from the contacts is in the range of ∼4%. The resulting solar cells showed front/rear efficiencies of 18.6–19.0%/14.9–15.3% (“p-type” cell) and 17.3–17.7%/18.1–18.5% (“n-type” cell) respectively at 1–5 suns. At 20–50% albedo of 1-sun illumination, similar energy production corresponds to 21.6–26.8% (n-type cell) and 21.6–26.1% (“p-type” cell) efficiency of a monofacial cell.

Research paper thumbnail of Passivation of boron-doped р+-Si emitters in the (p+nn+)Si solar cell structure with AlOx grown by ultrasonic spray pyrolysis

Solar Energy, 2013

ABSTRACT AlOx/(p+nn+)Cz–Si/IFO and ITO/AlOx/(p+nn+)Cz–Si/IFO solar cell structures have been fabr... more ABSTRACT AlOx/(p+nn+)Cz–Si/IFO and ITO/AlOx/(p+nn+)Cz–Si/IFO solar cell structures have been fabricated from n-type Czochralski (Cz) silicon wafers through boron and phosphorus diffusion for producing the p+-Si emitter and n+-Si layer, respectively. The In2O3:F (IFO), AlOx, and In2O3:Sn (ITO) films have been grown by ultrasonic spray pyrolysis at 475 �C, 330 �C, and 375 �C, respectively. The AlOx film thickness was varied in the range 27–108 nm, the annealing time at 330 �C in an Ar + 5% O2 atmosphere containing vapor of a 2M H2O solution in methanol – in the range 0–18 min, and the sheet resistance of the p+-Si emitter – in the range 28–133 X/h (varied through layer-by-layer chemical etching). We have studied the internal quantum efficiency (IQE) spectrum, photocurrent JIQE of the structures (evaluated from the IQE spectrum), as well as their photovoltage and pseudo-fill factor evaluated from Suns–Voc measurements. The results demonstrate that the level of p+-Si surface passivation increases with increasing AlOx film thickness and as a result of annealing. The optimal sheet resistance of the emitter is �65 X/h. The pseudo-efficiency of the optimized ITO/AlOx/(p+nn+)Cz–Si/IFO structures was 20.2% under front illumination.

Research paper thumbnail of Effect of conditions of deposition and annealing of indium oxide films doped with fluorine (IFO) on the photovoltaic properties of the IFO/p-Si heterojunction

Semiconductors, 2008

ABSTRACT In2O3:F (IFO) films were deposited onto crystalline silicon and glass by the pyrosol met... more ABSTRACT In2O3:F (IFO) films were deposited onto crystalline silicon and glass by the pyrosol method. The effect of temperature and oxygen in the course of deposition and also of subsequent annealings in various media on the photovoltaic properties of the IFO/Si structure was measured. It is found that IFO forms a rectifying contact to p-Si, makes it possible to obtain a high photovoltage U p = 586 mV and an internal quantum yield higher than 97% for the IFO/(pp +)Si structure, and features a low (0.3–0.4 Ω cm) resistivity. An increase in U p is stimulated by an increase in the temperature of the IFO deposition, a low content of oxygen in the carrier gas, and annealing in argon with methanol vapors. It is concluded that oxygen profoundly affects the surface of the IFO grains and that the transition layer greatly affects the photovoltaic properties of the IFO/(pp +)Si structures.

Research paper thumbnail of n-Si bifacial concentrator solar cell

Semiconductors, 2012

Various approaches have been developed for reducing the cost of the photoelectricity produced by ... more Various approaches have been developed for reducing the cost of the photoelectricity produced by silicon solar cells (SCs). Of highest priority among these approaches are improvement of the efficiency of the SCs, transition from p Si to n Si, light concentration, and use of bifacial SCs. In the present study, an SC combining all these approaches has been developed. In this SC, transparent conducting oxides serve as anti reflection and passivating electrodes in an indium-tin-oxide/(p + nn +) Si/indium-fluorine-oxide structure fabricated from Cz Si with wire contacts (Laminated Grid Cell design). The SC has front/rear efficiencies of 16.5-16.7/15.1-15.3% X (under 1-3 suns). This result is unique because the combination of bifaciality and concentrator operation has no analogs and the SC compares well with the world standard among both bifacial and concentrator SCs.

Research paper thumbnail of Simulation of optical properties of silicon solar cells textured with penetrating V-shaped grooves

Semiconductors, 2011

The coefficients of reflection (R), transmission (T), and absorption (A) of light for two wave le... more The coefficients of reflection (R), transmission (T), and absorption (A) of light for two wave lengths λ = 1000 and 1100 nm for silicon wafers that have thicknesses t = 50, 100, and 200 μm and are textured with penetrating V shaped grooves with various geometries have been calculated; the half width of groove's base w (10, 20, and 30 μm) and the depth of the groove d (0 ≤ d ≤ t) have been varied. In the case of an increase in the aspect ratio d/w (in the case of λ = 1100 nm), the absorption curve A(d/w) monotonically ascends from 6.6 to 67.6%, whereas, for λ = 1000 nm, a nontrivial dependence A(d/w) is observed: the absorption coeffi cient first increases to 54%, attains then a maximum of 97% at d/w = 3, and then decreases at d > t/2 for all values of w. This effect of a decrease in absorption with an increase in d/w distinguishes texturing with pene trating grooves from conventional surface texturing. Distributions of angles of deviations of photons in the plane of bottoms of grooves are obtained; these distributions are represented by a set of δ type functions.

Research paper thumbnail of Optimization of the deposition and annealing conditions of fluorine-doped indium oxide films for silicon solar cells

Semiconductors, 2013

ABSTRACT Fluorine-doped indium oxide (IFO) films are deposited onto (pp +)Si and (n +nn +)Si stru... more ABSTRACT Fluorine-doped indium oxide (IFO) films are deposited onto (pp +)Si and (n +nn +)Si structures made of single-crystal silicon by ultrasonic spray pyrolysis. The effect of the IFO deposition time and annealing time in an argon atmosphere with methanol vapor on the IFO chemical composition, the photovoltage and fill factor of the Illumination-U oc curves of IFO/(pp +)Si structures, and the sheet resistance of IFO/(n +nn +)Si structures, correlating with the IFO/(n +)Si contact resistance, is studied. The obtained features are explained by modification of the properties of the SiOx transition layer at the IFO/Si interface during deposition and annealing. Analysis of the results made it possible to optimize the fabrication conditions of solar cells based on IFO/(pp +)Si heterostructures and to increase their efficiency from 17% to a record 17.8%.

Research paper thumbnail of A New Type of High-Efficiency Bifacial Silicon Solar Cell with External Busbars and a Current-Collecting Wire Grid

Semiconductors, 2005

ABSTRACT Results regarding bifacial silicon solar cells with external busbars are presented. The ... more ABSTRACT Results regarding bifacial silicon solar cells with external busbars are presented. The cells consist of [n + p(n)p +] Cz-Si structures with a current-collecting system of new design: a laminated grid of wire external busbars (LGWEB). A LGWEB consists of a transparent conducting oxide film deposited onto a Si structure, busbars adjacent to the Si structure, and a contact wire grid attached simultaneously to the oxide and busbars using the low-temperature lamination method. Bifacial LGWEB solar cells demonstrate record high efficiency for similar devices: 17.7%(n-Si)/17.3%(p-Si) with 74–82% bifaciality for the smooth back surface and 16.3%(n-Si)/16.4%(p-Si) with 89% bifaciality for the textured back surface. It is shown that the LGWEB technology can provide an efficiency exceeding 21%.

Research paper thumbnail of Effect of the temperature during deposition of AlO x films by spray pyrolysis on their passivating properties in a silicon solar cell

Semiconductors, 2012

The effect of the deposition temperature of AlO x in the range 330-530°C by spray pyrolysis on th... more The effect of the deposition temperature of AlO x in the range 330-530°C by spray pyrolysis on the rear surface parameters of silicon (n + pp +)Cz Si/AlO x solar cells has been studied. It is found that, as the tem perature of AlO x deposition is increased, all parameters of the rear surfaces decrease; e.g., the photocurrent density decreases from 25.4 to 24.1 mA/cm 2 ; the photovoltage decreases from 611 to 598 mV; and the effi ciency decreases from 12.2 to 10.9%. This indicates that passivation of the p + type surface with AlO x films becomes less effective. It is concluded that, as the temperature of AlO x deposition is increased, the value of the positive charge incorporated into the nonstoichiometric interphase SiO x layer formed between c Si and AlO x in the course of AlO x deposition, which brings about screening of the negative charge localized at the AlO x-SiO x interface and, respectively, a decrease in the field induced passivation, increases.

Research paper thumbnail of Effect of the tin content on the composition and optical and electrical properties of ITO films deposited onto silicon and glass by ultrasonic spray pyrolysis

Semiconductors, 2012

With the aim of optimizing the properties of tin doped indium oxide (ITO) films as applied to sil... more With the aim of optimizing the properties of tin doped indium oxide (ITO) films as applied to sil icon solar cells, ~100 nm thick ITO films were deposited onto (nn +) Cz-Si and glass substrates by ultrasonic spray pyrolysis in argon at a temperature of 380°C. The relative Sn and In content in the film forming solu tion was varied in the range of [Sn]/[In] = 0-12 at %. Optimal parameters are exhibited by the films produced at [Sn]/[In] = 2-3 at % in the solution ([Sn]/([In] + [Sn]) = 5.2-5.3 at % in the film). For such films depos ited onto glass substrates, the effective absorptance weighted over the solar spectrum in the wavelength range from 300 to 1100 nm is 1.6-2.1%. The sheet resistance R s of the films deposited onto silicon and glass is, cor respondingly, 45-55 and 165-175 Ω ᮀ-1. After eight months of storage in air, the resistance R s of the optimal films remained unchanged; for the other films, the resistance R s increased: for the films on silicon and glass, the resistance R s became up to 2 and 14 times higher, respectively.

Research paper thumbnail of Laminated grid solar cells (LGCells) on multicrystalline silicon. Application of atomic hydrogen treatment

Semiconductors, 2011

For the first time, solar cells of laminated grid cell (LGCell) design are fabricated on multicry... more For the first time, solar cells of laminated grid cell (LGCell) design are fabricated on multicrystal line nontextured silicon (mc Si). An efficiency of 15.9% is achieved. The effect of (n + pp +) mc Si structure treatment by atomic hydrogen generated by a hot filament and microwave plasma is studied. Hydrogenation improves the parameters describing the dependence of the open circuit voltage on the radiation intensity and the long wavelength (λ = 1000 nm) sensitivity of the solar cell by 10-20%, which indicates that defects in mc Si are passivated. Hydrogenation of the emitter side results in an increase in the series resistance of the solar cell, a decrease in the short wavelength (λ = 400 nm) sensitivity by 30-35%, and the appearance of an oxygen peak in the energy dispersive spectra (EDS). These effects are eliminated by fine etching of the emitter.

Research paper thumbnail of Bifacial concentrator Ag-free crystalline n-type Si solar cell

Progress in Photovoltaics: Research and Applications, 2014

We report results obtained using an innovative approach for the fabrication of bifacial low-conce... more We report results obtained using an innovative approach for the fabrication of bifacial low-concentrator thin Ag-free n-type Cz-Si (Czochralski silicon) solar cells based on an indium tin oxide/(p + nn +)Cz-Si/indium fluorine oxide structure. The (p + nn +)Cz-Si structure was produced by boron and phosphorus diffusion from Band P-containing glasses deposited on the opposite sides of n-type Cz-Si wafers, followed by an etch-back step. Transparent conducting oxide (TCO) films, acting as antireflection electrodes, were deposited by ultrasonic spray pyrolysis on both sides. A copper wire contact pattern was attached by low-temperature (160°C) lamination simultaneously to the front and rear transparent conducting oxide layers as well as to the interconnecting ribbons located outside the structure. The shadowing from the contacts was~4%. The resulting solar cells, 25 × 25 mm 2 in dimensions, showed front/rear efficiencies of 17.6-17.9%/16.7-17.0%, respectively, at one to three suns (bifaciality of~95%). Even at one-sun front illumination and 20-50% one-sun rear illumination, such a cell will generate energy approaching that produced by a monofacial solar cell of 21-26% efficiency.

Research paper thumbnail of Inhibition of enzymatic indole-3-acetic acid oxidation by phenols

Phytochemistry, 1994

The influence of natural and unnatural phenolic inhibitors on peroxidase-catalyzed oxidation of i... more The influence of natural and unnatural phenolic inhibitors on peroxidase-catalyzed oxidation of indole-3-acetic acid (IAA) was investigated using chemiluminescent and spectrophotometric methods. The threshold effect under inhibition was observed for all studied phenolic compounds. The IAA oxidation stopped only if the concentration of inhibitor was more than some threshold value. The spontaneous reinitiation of the stopped reaction was also investigated. The system of chemical reactions, required for the description of threshold effect under inhibition and spontaneous reinitiation of stopped reaction, was proposed. Moreover, the effect of Hz02 on the inhibited IAA oxidation was studied. It was found that addition of HzOz caused a reinitiation of stopped reaction. Threshold effect was observed for the reinitiation. The reinitiation took place only when the concentration of Hz02 was more than a threshold value which depended on the inhibitor concentration. The total quantity of Hz02 required for the reaction reinitiation on the addition of H,02 a little at a time was more than that on addition by a single large portion. The results obtained are discussed in terms of free-radical chain reaction of enzymatic IAA oxidation.

Research paper thumbnail of Peroxidase‐catalyzed co‐oxidation of indole‐3‐acetic acid and xanthene dyes in the absence of hydrogen peroxide

FEBS Letters, 1993

The effect of xanthene dyes on the chemiluminescence from the aerobic indole‐3‐acetic acid (IAA) ... more The effect of xanthene dyes on the chemiluminescence from the aerobic indole‐3‐acetic acid (IAA) oxidation, catalyzed by horseradish peroxidase (HRP), was studied. The rate of IAA oxidation and dye destruction were controlled. It was found that the addition of dyes to the IAA/HRP/O2 system resulted in: (i) the appearance of emission in the region of dye fluorescence, (ii) an increase of the total chemiluminescence intensity, (iii) a decrease of the emission duration, (iv) the acceleration of IAA oxidation, and (v) slow bleaching of the dyes. The experimental results lead to the conclusion that all spectral and kinetic variations of the chemiluminescence from the IAA/HRP/O2 system which are caused by the addition of xanthene dyes, are the result of IAA‐dye co‐oxidation. Earlier published reports regarding energy transfer from electronically excited species, generated in the IAA/HRP/O2 system, to the xanthene dyes seem to be erroneous.

Research paper thumbnail of The Effect of Local Doping of the Polymer–Polymer Interface Using Cu2O Particles

Applied Sciences

Electrically conductive polymer materials are increasingly being used as electronic materials, fo... more Electrically conductive polymer materials are increasingly being used as electronic materials, for example, in thin-film transistors. However, the low mobility of charge carriers limits their use. One of the ways to increase the mobility of charge carriers can be the use of interface conductivity along the regions separating the two polymer films. It is important that it could be realized with non-conjugated polymers. There is no direct experimental evidence that the transport of charge carriers occurs along such an interface. It is impossible to deny the possibility of transport on the surfaces of polymer films. The purpose of this work is to study the current flow path in a multilayer sample by marking the polymer–polymer interface with a doping nanolayer of a Cu2O island film. Spectral methods in the field of electronic absorption of copper oxide were used to control the island film. The electronic parameters of the polymer–polymer interface were studied using injection methods a...

Research paper thumbnail of Non-Conjugated Copoly(Arylene Ether Ketone) for the Current-Collecting System of a Solar Cell with Indium Tin Oxide Electrode

Polymers, Feb 13, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Formation of low-reflection multicrystalline silicon surface by laser-induced structuring for application on silicon solar cells

SPIE Proceedings, 2010

The formation of laser-induced structures on the multicrystalline silicon surface has been invest... more The formation of laser-induced structures on the multicrystalline silicon surface has been investigated. Optimum performances of the surface structurization have been explored. A cardinal decrease in reflectance from modified surface has been discovered in a wide spectral range in comparison with the samples of chemically texturized monocrystalline silicon. The influence of subsequent chemical etching on the reflection spectra of the

Research paper thumbnail of Contact resistance of indium tin oxide and fluorine-doped indium oxide films grown by ultrasonic spray pyrolysis to diffusion layers in silicon solar cells

Solar Energy Materials and Solar Cells, 2015

A simple method is described for estimating the contact resistance between a transparent conducti... more A simple method is described for estimating the contact resistance between a transparent conducting oxide film and a diffusion layer in a silicon solar cell. We have investigated the effect of film growth temperature on the contact resistance between n þ þ-Si and p þ þ-Si layers and In 2 O 3 :Sn (ITO) and In 2 O 3 : F (IFO) films grown by ultrasonic spray pyrolysis. The effect of growth temperature on the properties of the SiO x layer in IFO/SiO x /n þ þ-Si structures has been studied by Fourier transform infrared absorption spectroscopy. The process for IFO deposition on n þ þ-Si layers has been modified in order to reduce the IFO/SiO x /n þ þ-Si contact resistance. The use of modified IFO has reduced the series resistance of an ITO/ (p þ þ nn þ þ)Cz-Si/IFO bifacial solar cell for low-concentration applications by 0.13 Ω cm 2 , from 0.39 to 0.26 Ω cm 2 ; extended its operating range of concentration ratios by a factor of 1.5, from 1-3.5 Â to 1-5.3 Â ; and improved its efficiency in the operating range from 17.6-17.9 to 17.7-18.2%.

Research paper thumbnail of Crystalline silicon solar cells with laser ablated penetrating V-grooves: Modeling and experiment

physica status solidi (a), 2012

Different approaches are under elaboration aimed at the cost reduction of solar electricity. 3D p... more Different approaches are under elaboration aimed at the cost reduction of solar electricity. 3D penetrating emitter solar cells are expected to offer performance enhancement at lower costs, using low carrier lifetime cheaper silicon. Using laser ablation, we have prepared indium-fluorine-oxide/(n þ pp þ)Cz-Si/ indium-tin-oxide bifacial silicon solar cells with deep (110-120 mm) penetrating V-shaped emitter with aspect ratio of 3-4 (height to half-width of the V-grooves). Compared with the reference cell textured with conventional random pyramids and thus not damaged by laser action, which showed front/rear active area photocurrents of 41.1/33.3 mA cm À2 , V-grooved solar cells showed only slightly less front photocurrent of 40.1-40.7 mA cm À2 , whereas the superior rear photocurrent of 34.2 mA cm À2. The latter indicates that deep penetrating emitter is especially useful in the case of bifacial solar cells. The best pseudo-efficiency for V-grooved cell of 19.5% with estimated bifaciality of $80% was obtained for the cell that has been subjected to the smallest laser action during Vgrooving. In addition, ray-tracing model was applied to calculate efficiency of light absorption by a V-grooved silicon solar cell for wavelengths in the range from 400 to 1200 nm. The depth of the grooves was varied from 0.05t to wafer's thickness t. The obtained experimental and computational results confirm that the design of crystalline silicon solar cell based on deep penetrating V-shaped emitter makes possible to obtain high-efficiency solar cells even in the case of low-quality silicon wafers. Silicon wafer with deep penetrating V-grooved emitter.

Research paper thumbnail of Bifacial low concentrator argentum free crystalline silicon solar cells based on ARC of TCO and current collecting grid of copper wire

AIP Conference Proceedings, 2013

Results obtained in frame of an innovative approach for fabrication of the bifacial low concentra... more Results obtained in frame of an innovative approach for fabrication of the bifacial low concentrator Ag free Cz silicon solar cells based on Indium-Tin-Oxide(ITO)/(p + nn +)Cz-Si/Indium-Fluorine-Oxide (IFO) structure (n-type cell) as well as on IFO/(n + pp +)Cz-Si/ITO structure (p-type cell) are presented in this work. The (p + nn +)Cz-Si and (n + pp +)Cz-Si structures were produced by diffusion of boron and phosphorus from deposited Band P-containing glasses followed by an etch-back step. The n + surface of the structures was textured, whereas the p + surface remained planar. Transparent conducting oxide (TCO) films, which act as passivating and antireflection electrodes, were deposited by ultrasonic spray pyrolysis method on both sides. The contact pattern of copper wire was attached by the lowtemperature (160 °C) lamination method simultaneously to the front and rear TCO layers as well as to the interconnecting ribbons arranged outside the structure. The shadowing from the contacts is in the range of ~4%. The resulting solar cells showed front/rear efficiencies of 18.6-19.0%/14.9-15.3% (p-type cell) and 17.5-17.9%/16.5-17.0% (n-type cell) respectively at 1-5 suns. Even for 1 sun illumination at 20-50% albedo, similar energy production corresponds to 21.6-26.1% (p-type cell) and 20.8-25.8% (n-type cell) efficiency of a monofacial cell.

Research paper thumbnail of Fluorine doped indium oxide films for silicon solar cells

Thin Solid Films, 2009

The effect of conditions of preparation of the In 2 O 3 :F(IFO)/(pp +)Si solar cell (SC) by pyros... more The effect of conditions of preparation of the In 2 O 3 :F(IFO)/(pp +)Si solar cell (SC) by pyrosol method was systematically studied with the goal to maximize its photovoltage. Heterojunction IFO/(pp +)Si SC was obtained with the efficiency of 16.6% and photovoltage of 617 mV as well as the IFO/(n + pp +)Si SC with the efficiency of 19.2% using the following obtained optimal conditions: film-forming solution: 0.2 M InCl 3 +0.05 M NH 4 F+0.1 M H 2 O in methanol; carrier gas-Ar+ 5% O 2 ; deposition temperature-480°C; duration of deposition-2 min; two-minute annealing in argon with sprayed methanol at a temperature of 380°C.

Research paper thumbnail of Concentrator bifacial Ag-free LGCells

Solar Energy, 2014

ABSTRACT Results obtained for the bifacial low concentrator Ag free Cz silicon solar cells based ... more ABSTRACT Results obtained for the bifacial low concentrator Ag free Cz silicon solar cells based on Indium–Tin–Oxide(ITO)/(p+nn+)Cz–Si/Indium–Fluorine–Oxide (IFO) structure (“n-type” cell) as well as on IFO/(n+pp+)Cz–Si/ITO structure (“p-type” cell) are presented in this work. The (p+nn+)Cz–Si and (n+pp+)Cz–Si structures were produced by diffusion of boron and phosphorus from deposited B- and P-containing glasses followed by an etch-back step. The n+ surface of the structures was textured, whereas the p+ surface remained planar. Transparent Conducting Oxide (TCO) films, which act as antireflection electrodes, were deposited by ultrasonic spray pyrolysis method on both sides. The contact pattern of copper wire was attached by the low-temperature (160 °C) lamination method simultaneously to the front and rear TCO layers as well as to the interconnecting ribbons arranged outside the structure. The shadowing from the contacts is in the range of ∼4%. The resulting solar cells showed front/rear efficiencies of 18.6–19.0%/14.9–15.3% (“p-type” cell) and 17.3–17.7%/18.1–18.5% (“n-type” cell) respectively at 1–5 suns. At 20–50% albedo of 1-sun illumination, similar energy production corresponds to 21.6–26.8% (n-type cell) and 21.6–26.1% (“p-type” cell) efficiency of a monofacial cell.

Research paper thumbnail of Passivation of boron-doped р+-Si emitters in the (p+nn+)Si solar cell structure with AlOx grown by ultrasonic spray pyrolysis

Solar Energy, 2013

ABSTRACT AlOx/(p+nn+)Cz–Si/IFO and ITO/AlOx/(p+nn+)Cz–Si/IFO solar cell structures have been fabr... more ABSTRACT AlOx/(p+nn+)Cz–Si/IFO and ITO/AlOx/(p+nn+)Cz–Si/IFO solar cell structures have been fabricated from n-type Czochralski (Cz) silicon wafers through boron and phosphorus diffusion for producing the p+-Si emitter and n+-Si layer, respectively. The In2O3:F (IFO), AlOx, and In2O3:Sn (ITO) films have been grown by ultrasonic spray pyrolysis at 475 �C, 330 �C, and 375 �C, respectively. The AlOx film thickness was varied in the range 27–108 nm, the annealing time at 330 �C in an Ar + 5% O2 atmosphere containing vapor of a 2M H2O solution in methanol – in the range 0–18 min, and the sheet resistance of the p+-Si emitter – in the range 28–133 X/h (varied through layer-by-layer chemical etching). We have studied the internal quantum efficiency (IQE) spectrum, photocurrent JIQE of the structures (evaluated from the IQE spectrum), as well as their photovoltage and pseudo-fill factor evaluated from Suns–Voc measurements. The results demonstrate that the level of p+-Si surface passivation increases with increasing AlOx film thickness and as a result of annealing. The optimal sheet resistance of the emitter is �65 X/h. The pseudo-efficiency of the optimized ITO/AlOx/(p+nn+)Cz–Si/IFO structures was 20.2% under front illumination.

Research paper thumbnail of Effect of conditions of deposition and annealing of indium oxide films doped with fluorine (IFO) on the photovoltaic properties of the IFO/p-Si heterojunction

Semiconductors, 2008

ABSTRACT In2O3:F (IFO) films were deposited onto crystalline silicon and glass by the pyrosol met... more ABSTRACT In2O3:F (IFO) films were deposited onto crystalline silicon and glass by the pyrosol method. The effect of temperature and oxygen in the course of deposition and also of subsequent annealings in various media on the photovoltaic properties of the IFO/Si structure was measured. It is found that IFO forms a rectifying contact to p-Si, makes it possible to obtain a high photovoltage U p = 586 mV and an internal quantum yield higher than 97% for the IFO/(pp +)Si structure, and features a low (0.3–0.4 Ω cm) resistivity. An increase in U p is stimulated by an increase in the temperature of the IFO deposition, a low content of oxygen in the carrier gas, and annealing in argon with methanol vapors. It is concluded that oxygen profoundly affects the surface of the IFO grains and that the transition layer greatly affects the photovoltaic properties of the IFO/(pp +)Si structures.

Research paper thumbnail of n-Si bifacial concentrator solar cell

Semiconductors, 2012

Various approaches have been developed for reducing the cost of the photoelectricity produced by ... more Various approaches have been developed for reducing the cost of the photoelectricity produced by silicon solar cells (SCs). Of highest priority among these approaches are improvement of the efficiency of the SCs, transition from p Si to n Si, light concentration, and use of bifacial SCs. In the present study, an SC combining all these approaches has been developed. In this SC, transparent conducting oxides serve as anti reflection and passivating electrodes in an indium-tin-oxide/(p + nn +) Si/indium-fluorine-oxide structure fabricated from Cz Si with wire contacts (Laminated Grid Cell design). The SC has front/rear efficiencies of 16.5-16.7/15.1-15.3% X (under 1-3 suns). This result is unique because the combination of bifaciality and concentrator operation has no analogs and the SC compares well with the world standard among both bifacial and concentrator SCs.

Research paper thumbnail of Simulation of optical properties of silicon solar cells textured with penetrating V-shaped grooves

Semiconductors, 2011

The coefficients of reflection (R), transmission (T), and absorption (A) of light for two wave le... more The coefficients of reflection (R), transmission (T), and absorption (A) of light for two wave lengths λ = 1000 and 1100 nm for silicon wafers that have thicknesses t = 50, 100, and 200 μm and are textured with penetrating V shaped grooves with various geometries have been calculated; the half width of groove's base w (10, 20, and 30 μm) and the depth of the groove d (0 ≤ d ≤ t) have been varied. In the case of an increase in the aspect ratio d/w (in the case of λ = 1100 nm), the absorption curve A(d/w) monotonically ascends from 6.6 to 67.6%, whereas, for λ = 1000 nm, a nontrivial dependence A(d/w) is observed: the absorption coeffi cient first increases to 54%, attains then a maximum of 97% at d/w = 3, and then decreases at d > t/2 for all values of w. This effect of a decrease in absorption with an increase in d/w distinguishes texturing with pene trating grooves from conventional surface texturing. Distributions of angles of deviations of photons in the plane of bottoms of grooves are obtained; these distributions are represented by a set of δ type functions.

Research paper thumbnail of Optimization of the deposition and annealing conditions of fluorine-doped indium oxide films for silicon solar cells

Semiconductors, 2013

ABSTRACT Fluorine-doped indium oxide (IFO) films are deposited onto (pp +)Si and (n +nn +)Si stru... more ABSTRACT Fluorine-doped indium oxide (IFO) films are deposited onto (pp +)Si and (n +nn +)Si structures made of single-crystal silicon by ultrasonic spray pyrolysis. The effect of the IFO deposition time and annealing time in an argon atmosphere with methanol vapor on the IFO chemical composition, the photovoltage and fill factor of the Illumination-U oc curves of IFO/(pp +)Si structures, and the sheet resistance of IFO/(n +nn +)Si structures, correlating with the IFO/(n +)Si contact resistance, is studied. The obtained features are explained by modification of the properties of the SiOx transition layer at the IFO/Si interface during deposition and annealing. Analysis of the results made it possible to optimize the fabrication conditions of solar cells based on IFO/(pp +)Si heterostructures and to increase their efficiency from 17% to a record 17.8%.

Research paper thumbnail of A New Type of High-Efficiency Bifacial Silicon Solar Cell with External Busbars and a Current-Collecting Wire Grid

Semiconductors, 2005

ABSTRACT Results regarding bifacial silicon solar cells with external busbars are presented. The ... more ABSTRACT Results regarding bifacial silicon solar cells with external busbars are presented. The cells consist of [n + p(n)p +] Cz-Si structures with a current-collecting system of new design: a laminated grid of wire external busbars (LGWEB). A LGWEB consists of a transparent conducting oxide film deposited onto a Si structure, busbars adjacent to the Si structure, and a contact wire grid attached simultaneously to the oxide and busbars using the low-temperature lamination method. Bifacial LGWEB solar cells demonstrate record high efficiency for similar devices: 17.7%(n-Si)/17.3%(p-Si) with 74–82% bifaciality for the smooth back surface and 16.3%(n-Si)/16.4%(p-Si) with 89% bifaciality for the textured back surface. It is shown that the LGWEB technology can provide an efficiency exceeding 21%.

Research paper thumbnail of Effect of the temperature during deposition of AlO x films by spray pyrolysis on their passivating properties in a silicon solar cell

Semiconductors, 2012

The effect of the deposition temperature of AlO x in the range 330-530°C by spray pyrolysis on th... more The effect of the deposition temperature of AlO x in the range 330-530°C by spray pyrolysis on the rear surface parameters of silicon (n + pp +)Cz Si/AlO x solar cells has been studied. It is found that, as the tem perature of AlO x deposition is increased, all parameters of the rear surfaces decrease; e.g., the photocurrent density decreases from 25.4 to 24.1 mA/cm 2 ; the photovoltage decreases from 611 to 598 mV; and the effi ciency decreases from 12.2 to 10.9%. This indicates that passivation of the p + type surface with AlO x films becomes less effective. It is concluded that, as the temperature of AlO x deposition is increased, the value of the positive charge incorporated into the nonstoichiometric interphase SiO x layer formed between c Si and AlO x in the course of AlO x deposition, which brings about screening of the negative charge localized at the AlO x-SiO x interface and, respectively, a decrease in the field induced passivation, increases.

Research paper thumbnail of Effect of the tin content on the composition and optical and electrical properties of ITO films deposited onto silicon and glass by ultrasonic spray pyrolysis

Semiconductors, 2012

With the aim of optimizing the properties of tin doped indium oxide (ITO) films as applied to sil... more With the aim of optimizing the properties of tin doped indium oxide (ITO) films as applied to sil icon solar cells, ~100 nm thick ITO films were deposited onto (nn +) Cz-Si and glass substrates by ultrasonic spray pyrolysis in argon at a temperature of 380°C. The relative Sn and In content in the film forming solu tion was varied in the range of [Sn]/[In] = 0-12 at %. Optimal parameters are exhibited by the films produced at [Sn]/[In] = 2-3 at % in the solution ([Sn]/([In] + [Sn]) = 5.2-5.3 at % in the film). For such films depos ited onto glass substrates, the effective absorptance weighted over the solar spectrum in the wavelength range from 300 to 1100 nm is 1.6-2.1%. The sheet resistance R s of the films deposited onto silicon and glass is, cor respondingly, 45-55 and 165-175 Ω ᮀ-1. After eight months of storage in air, the resistance R s of the optimal films remained unchanged; for the other films, the resistance R s increased: for the films on silicon and glass, the resistance R s became up to 2 and 14 times higher, respectively.

Research paper thumbnail of Laminated grid solar cells (LGCells) on multicrystalline silicon. Application of atomic hydrogen treatment

Semiconductors, 2011

For the first time, solar cells of laminated grid cell (LGCell) design are fabricated on multicry... more For the first time, solar cells of laminated grid cell (LGCell) design are fabricated on multicrystal line nontextured silicon (mc Si). An efficiency of 15.9% is achieved. The effect of (n + pp +) mc Si structure treatment by atomic hydrogen generated by a hot filament and microwave plasma is studied. Hydrogenation improves the parameters describing the dependence of the open circuit voltage on the radiation intensity and the long wavelength (λ = 1000 nm) sensitivity of the solar cell by 10-20%, which indicates that defects in mc Si are passivated. Hydrogenation of the emitter side results in an increase in the series resistance of the solar cell, a decrease in the short wavelength (λ = 400 nm) sensitivity by 30-35%, and the appearance of an oxygen peak in the energy dispersive spectra (EDS). These effects are eliminated by fine etching of the emitter.

Research paper thumbnail of Bifacial concentrator Ag-free crystalline n-type Si solar cell

Progress in Photovoltaics: Research and Applications, 2014

We report results obtained using an innovative approach for the fabrication of bifacial low-conce... more We report results obtained using an innovative approach for the fabrication of bifacial low-concentrator thin Ag-free n-type Cz-Si (Czochralski silicon) solar cells based on an indium tin oxide/(p + nn +)Cz-Si/indium fluorine oxide structure. The (p + nn +)Cz-Si structure was produced by boron and phosphorus diffusion from Band P-containing glasses deposited on the opposite sides of n-type Cz-Si wafers, followed by an etch-back step. Transparent conducting oxide (TCO) films, acting as antireflection electrodes, were deposited by ultrasonic spray pyrolysis on both sides. A copper wire contact pattern was attached by low-temperature (160°C) lamination simultaneously to the front and rear transparent conducting oxide layers as well as to the interconnecting ribbons located outside the structure. The shadowing from the contacts was~4%. The resulting solar cells, 25 × 25 mm 2 in dimensions, showed front/rear efficiencies of 17.6-17.9%/16.7-17.0%, respectively, at one to three suns (bifaciality of~95%). Even at one-sun front illumination and 20-50% one-sun rear illumination, such a cell will generate energy approaching that produced by a monofacial solar cell of 21-26% efficiency.

Research paper thumbnail of Inhibition of enzymatic indole-3-acetic acid oxidation by phenols

Phytochemistry, 1994

The influence of natural and unnatural phenolic inhibitors on peroxidase-catalyzed oxidation of i... more The influence of natural and unnatural phenolic inhibitors on peroxidase-catalyzed oxidation of indole-3-acetic acid (IAA) was investigated using chemiluminescent and spectrophotometric methods. The threshold effect under inhibition was observed for all studied phenolic compounds. The IAA oxidation stopped only if the concentration of inhibitor was more than some threshold value. The spontaneous reinitiation of the stopped reaction was also investigated. The system of chemical reactions, required for the description of threshold effect under inhibition and spontaneous reinitiation of stopped reaction, was proposed. Moreover, the effect of Hz02 on the inhibited IAA oxidation was studied. It was found that addition of HzOz caused a reinitiation of stopped reaction. Threshold effect was observed for the reinitiation. The reinitiation took place only when the concentration of Hz02 was more than a threshold value which depended on the inhibitor concentration. The total quantity of Hz02 required for the reaction reinitiation on the addition of H,02 a little at a time was more than that on addition by a single large portion. The results obtained are discussed in terms of free-radical chain reaction of enzymatic IAA oxidation.

Research paper thumbnail of Peroxidase‐catalyzed co‐oxidation of indole‐3‐acetic acid and xanthene dyes in the absence of hydrogen peroxide

FEBS Letters, 1993

The effect of xanthene dyes on the chemiluminescence from the aerobic indole‐3‐acetic acid (IAA) ... more The effect of xanthene dyes on the chemiluminescence from the aerobic indole‐3‐acetic acid (IAA) oxidation, catalyzed by horseradish peroxidase (HRP), was studied. The rate of IAA oxidation and dye destruction were controlled. It was found that the addition of dyes to the IAA/HRP/O2 system resulted in: (i) the appearance of emission in the region of dye fluorescence, (ii) an increase of the total chemiluminescence intensity, (iii) a decrease of the emission duration, (iv) the acceleration of IAA oxidation, and (v) slow bleaching of the dyes. The experimental results lead to the conclusion that all spectral and kinetic variations of the chemiluminescence from the IAA/HRP/O2 system which are caused by the addition of xanthene dyes, are the result of IAA‐dye co‐oxidation. Earlier published reports regarding energy transfer from electronically excited species, generated in the IAA/HRP/O2 system, to the xanthene dyes seem to be erroneous.