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Article
Publication date: 11 January 2018

Piotr Sobik, Radoslaw Pawlowski, Bartlomiej Pawlowski, Boguslaw Drabczyk and Kazimierz Drabczyk

The purpose of this paper is to present results of the studies on modification of ethylene-vinyl acetate (EVA) encapsulation foil to be used as thermal interface material (TIM)…

Abstract

Purpose

The purpose of this paper is to present results of the studies on modification of ethylene-vinyl acetate (EVA) encapsulation foil to be used as thermal interface material (TIM). It is estimated that poor thermal management in electronic devices can cause over 50 per cent of failures. As the junction temperature rises, the failure rate for electronics increases exponentially. To ensure sufficient heat transfer from its source, TIMs are used in various circuits. On the other hand, it is important to ensure high electric resistivity of the designed TIM.

Design/methodology/approach

The focus of the investigation was twofold: modification of EVA with both graphene oxide (GO) and silver nanopowder (nAg); and TIM applicability through lamination of photovoltaic cells with standard and modified EVA foil. The main problem of a new type of encapsulant is proper gas evacuation during the lamination process. For this reason, reference and modified samples were compared taking into account the percentage of gas bubbles in visible volume of laminated TIM. Finally, reference and modified TIM samples were compared using differential scanning calorimetry (DSC) and laser flash analysis (LFA) measurements.

Findings

The proper parameters of the lamination process for the modified EVA foil - with both GO and organometallic nAg particles - were selected. The nAg addition results in an increase in thermal conductivity of the proposed compositions with respect to unmodified EVA foil, which was confirmed by DSC and LFA measurements.

Originality/value

The experiments confirmed the potential application of both EVA foil as a matrix for TIM material and nAg with GO as an active agent. Proposed composition can bring additional support to a solar cell or other electronic components through effective heat removal, which increases its performance.

Details

Circuit World, vol. 44 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 20 June 2019

Kazimierz Drabczyk, Piotr Sobik, Zbigniew Starowicz, Katarzyna Gawlińska, Anna Pluta and Bogusław Drabczyk

The photovoltaic modules with front glass as a protective layer are the most popular type in the industry, but for some applications it can be considered as too heavy. One of the…

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Abstract

Purpose

The photovoltaic modules with front glass as a protective layer are the most popular type in the industry, but for some applications it can be considered as too heavy. One of the approaches is to laminate the cells using PMMA [Poly(methyl methacrylate)] as the front layer. This polymer has good mechanical strength and optical properties but exhibits low adhesion to lamination foil. To increase adhesion between these two materials, PMMA surface treatment may be required.

Design/methodology/approach

To examine the PMMA treatment influence on the sample, adhesion samples’ surfaces were modified by grinding and laser cutting. Also two types of PMMA available in the market were tested, namely, smooth and satin types. The quality of lamination was determined using two methods, namely, tear test with recorded maximal tear force achieved for the samples, and environment chamber tests, in which the system resistance against the cyclic temperature variation was evaluated.

Findings

Additional treatment of the PMMA surface lead to increased adhesion of the lamination foil used. Ethylene-vinyl acetate foil in the PMMA system is sensitive to temperature variation, which can lead to system delamination, whereas polyvinyl butyral foil exhibits better environmental performance and even its adhesion to PMMA is lower.

Originality/value

This paper presents atypical surface modification methods that contributed to higher adhesion of lamination systems in glass-free solar modules. Glass front sheet and polymeric backsheet were replaced with PMMA. As the adhesion mechanism in the PMMA-lamination foil system differs from that in the traditional glass system, different PMMA surface treatments need to be evaluated.

Details

Microelectronics International, vol. 36 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 15 January 2018

Kazimierz Drabczyk

In this paper, results of the studies on the copper deposition on screen-printed fine-line front electrode of the solar cell were presented. The silver consumption is an important…

Abstract

Purpose

In this paper, results of the studies on the copper deposition on screen-printed fine-line front electrode of the solar cell were presented. The silver consumption is an important problem according to growing silver prices. The proposed solution of those problems might be printing of a very thin silver seed layer and subsequent copper plating. This process can be an alternative for typically used screen printing. The purpose of this study was the optimization of the finger path fabrication process to obtain required geometric of fingers for copper deposition.

Design/methodology/approach

In this paper, double-step metallization process was analyzed. The first step of an electrode formation is screen printing, the second one is copper electrodeposition. Presented investigations were focused on the optimization of the finger path fabrication process to obtain required geometric dimensions and sharp border of fingers. The morphology of the electrodes was characterized by scanning electron microscope before and after copper deposition. The X-ray analysis of elemental arrangement and cross-section profiles of fingers were made using energy-dispersive X-ray fluorescence spectrometer.

Findings

Presented investigations were focused on the optimization of the finger path fabrication process to obtain required geometric dimensions and sharp border of fingers without any silver particles. The main problem of non-uniform silver paste distribution close to the border of printed finger paths was eliminated by selection of appropriate paste and printing parameters. The obtained coatings were soft, ductile and bright.

Originality/value

The novelty of the presented approach is modification of the printing parameters, especially for copper deposition. In this paper, the reasons of the widening of electrodes during the copper deposition process is analyzed.

Details

Soldering & Surface Mount Technology, vol. 30 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 18 June 2019

Piotr Sobik, Radosław Pawłowski, Anna Pluta, Olgierd Jeremiasz, Kazimierz Drabczyk, Grażyna Kulesza-Matlak and Paweł Antoni Zięba

The purpose of this paper is to investigate the behavior of interconnections between solar cells in a glass-free solar modules. As glass weight can be a limitation, it is still…

Abstract

Purpose

The purpose of this paper is to investigate the behavior of interconnections between solar cells in a glass-free solar modules. As glass weight can be a limitation, it is still interesting to investigate other types of systems, especially when the glass was replaced with a polymeric front sheet. Such systems can be more sensitive for the solar cell interconnection ribbon fatigue.

Design/methodology/approach

To examine this effect, the set of glass-based and glass-free modules were prepared using various ribbon thickness and treatment concerning its stretching or curving before lamination. Furthermore, additional reinforcement of the connection between the ribbon and the solar cell was proposed. The prepared modules were exposed to the cyclic temperature variation in the environment chamber. The number of cycles after which the interconnection maintains its conductivity was noted.

Findings

Changing the outer layers into more elastic ones requires additional care for the ribbon treatment because interconnections become more sensitive for a system relative displacement. To secure interconnection before fatigue an additional curving of ribbon between solar cells can be introduced whereas the best results were obtained for a system with aluminum plate laminated as an interlayer.

Originality/value

The paper presents a new system of a glass-free solar module based on epoxy-glass fiber composite as a backsheet. The glass front sheet was replaced with an elastic, transparent polymer. Such construction can be used in a system where the glass weight is a limitation. As glass has a structural function in traditional modules and limits fatigues of interconnections the proposed system requires additional ribbon treatment to preserve long module life-span.

Details

Microelectronics International, vol. 36 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 7 August 2017

Wojciech Filipowski, Edyta Wrobel, Kazimierz Drabczyk, Krzysztof Waczynski, Grazyna Kulesza-Matlak and Marek Lipinski

The main aim of this study was a preparation development of dopant solution (DS) which can be deposited by a spray-on method and subsequently allows obtaining the n+ emitter layer…

Abstract

Purpose

The main aim of this study was a preparation development of dopant solution (DS) which can be deposited by a spray-on method and subsequently allows obtaining the n+ emitter layer with surface resistance in the range of 65-80 Ω−1. The intention of chosen spray-on method was to gain a cheaper way of dopant source deposition, compared to the commonly used methods, which is of particular importance for the new low-cost production processes.

Design/methodology/approach

This paper presents the sequence in producing a spray-on glass solution (DS) with very high concentration of phosphorus, which allows to perform diffusion doping at relatively low temperatures. DS contained deionized water, ethyl alcohol, tetraethoxysilane and othophosphoric acid.

Findings

The sequence in producing a DS was performed with respect to enabling the application to silicon wafers by spray-on method. Furthermore, the equations defined density and viscosity of DS in term of storage time were referred to determine the possibility of applying this solution by spray-on method. Besides, the dependence of the emitter surface resistance on the doping (diffusion) time was determined. Accordingly, optimal process conditions were specified.

Originality/value

The paper presents a new, so far unpublished composition of DS with very high concentration of phosphorus, which can be applied using a spray-on method. Moreover, original are also investigations respecting some properties of obtained DS relative to storage time.

Details

Microelectronics International, vol. 34 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 2 July 2018

Wojciech Filipowski, Kazimierz Drabczyk, Edyta Wróbel, Piotr Sobik, Krzysztof Waczynski and Natalia Waczynska-Niemiec

The purpose of this paper is to develop a method of preparing spray-on dopant solutions that enable obtaining a p+ region forming a back-surface field (BSF) during the diffusion…

Abstract

Purpose

The purpose of this paper is to develop a method of preparing spray-on dopant solutions that enable obtaining a p+ region forming a back-surface field (BSF) during the diffusion doping process. The spray-on method used allows to decrease the costs of dopant solution application, which is particularly significant for new low-cost production processes.

Design/methodology/approach

This paper presents steps of production of high concentration boron dopant solutions enabling diffusion doping of crystalline p-type silicon surfaces. To check the fabricated dopant solutions for stability and suitability for spray-on application, their viscosity and density were measured in week-long intervals. The dopant solutions described in this paper were used in a series of diffusion doping processes to confirm their suitability for BSF production.

Findings

A method of preparing dopant solutions with parameters enabling depositing them on silicon wafers by the spray-on method has been established. Due to hygroscopic properties of the researched dopant solutions, a maximum surrounding atmosphere humidity has been established. The solutions should not be applied by the spray-on method, if this humidity value is exceeded. The conducted derivatographic examination enabled establishing optimal drying conditions.

Originality/value

The paper presents a new composition of a dopant solution which contains high concentration of boron and may be applied by the spray-on method. Derivatographic examination results, as well as equations describing the relation between dopant solution density and viscosity and storage time are also original for this research. The established dependencies between the sheet resistance of the fabricated BSF and the diffusion doping time are other new elements described in the paper.

Details

Microelectronics International, vol. 35 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 August 2016

Kazimierz Drabczyk, Jaroslaw Domaradzki, Grazyna Kulesza-Matlak, Marek Lipinski and Danuta Kaczmarek

The purpose of this paper was investigation and comparison of electrical and optical properties of crystalline silicon solar cells with ITO or TiO2 coating. The ITO, similar to TiO…

Abstract

Purpose

The purpose of this paper was investigation and comparison of electrical and optical properties of crystalline silicon solar cells with ITO or TiO2 coating. The ITO, similar to TiO2, is very well transparent in the visible part of optical radiation; however, its low resistivity (lower that 10-3 Ohm/cm) makes it possible to use simultaneously as a transparent electrode for collection of photo-generated electrical charge carriers. This might also invoke increasing the distance between screen-printed metal fingers at the front of the solar cell that would increase of the cell’s active area. Performed optical investigation showed that applied ITO thin film fulfill standard requirements according to antireflection properties when it was deposited on the surface of silicon solar cell.

Design/methodology/approach

Two sets of samples were prepared for comparison. In the first one, the ITO thin film was deposited directly on the crystalline silicon substrate with highly doped emitter region. In the second case, the TCO film was deposited on the same type of silicon substrate but with additional ultrathin SiO2 passivation. The fingers lines of 80 μm width were then screen-printed on the ITO layer with two different spaces between fingers for each set. The influence of application of the ITO electrode and the type of metal electrodes patterns on the electrical performance of the prepared solar cells was investigated through optical and electrical measurements.

Findings

The electrical parameters such as short-circuit current (Jsc), open circuit voltage (Voc), fill factor (FF) and conversion efficiency were determined on a basis of I-V characteristics. Short-circuit current density (Jsc) was equal to 32 mA/cm2 for a solar cell with a typical antireflection layer and 31.5 mA/cm2 for the cell with ITO layer, respectively. Additionally, electroluminescence of prepared cells was measured and analysed.

Originality/value

The influence of the properties of ITO electrode on the electrical performance of crystalline silicon solar cells was investigated through complex optical, electrical and electroluminescence measurements.

Details

Microelectronics International, vol. 33 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 August 2016

Kazimierz Drabczyk, Edyta Wróbel, Grazyna Kulesza-Matlak, Wojciech Filipowski, Krzysztof Waczynski and Marek Lipinski

The purpose of this study is comparison of the diffusion processes performed using the commercial available dopant paste made by Filmtronics and the original prepared liquid…

Abstract

Purpose

The purpose of this study is comparison of the diffusion processes performed using the commercial available dopant paste made by Filmtronics and the original prepared liquid dopant solution. To decrease prices of industrially produced silicon-based solar cells, the new low-cost production processes are necessary. The main components of most popular silicon solar cells are with diffused emitter layer, passivation, anti-reflective layers and metal electrodes. This type of cells is prepared usually using phosphorus oxychloride diffusion source and metal pastes for screen printing. The diffusion process in diffusion furnace with quartz tube is slow, complicated and requires expensive equipment. The alternative for this technology is very fast in-line processing using the belt furnaces as an equipment. This approach requires different dopant sources.

Design/methodology/approach

In this work, the diffusion processes were made for two different types of dopant sources. The first one was the commercial available dopant paste from Filmtronics and the second one was the original prepared liquid dopant solution. The investigation was focused on dopant sources fabrication and diffusion processes. The doping solution was made in two stages. In the first stage, a base solution (without dopants) was made: dropwise deionized (DI) water and ethyl alcohol were added to a solution consisting of tetraethoxysilane (TEOS) and 99.8 per cent ethyl alcohol. Next, to the base solution, orthophosphoric acid dissolved in ethyl alcohol was added.

Findings

Diffused emitter layers with sheet resistance around 60 Ω/sq were produced on solar grade monocrystalline silicon wafers using two types of dopant sources.

Originality/value

In this work, the diffusion processes were made for two different types of dopant sources. The first one was the commercial available dopant paste from Filmtronics and the second one was the original prepared liquid dopant solution.

Details

Microelectronics International, vol. 33 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 3 August 2015

Kazimierz Drabczyk, Robert P. Socha and Agata Skwarek

The aim of this paper is to present results of investigations carried out on the front electrode of solar cells. Nowadays, most worldwide solar cell production is dominated by…

Abstract

Purpose

The aim of this paper is to present results of investigations carried out on the front electrode of solar cells. Nowadays, most worldwide solar cell production is dominated by monocrystalline and polycrystalline silicon as a base material. In such cells, the electrical carriers are collected by the system of metallic paths fabricated on a silicon surface. One possible way to increase cell efficiency and reduce the production costs of solar modules is to replace the expensive silver by cheaper copper in front metallic electrodes.

Design/methodology/approach

The paper presents results of investigations performed on the front electrode of the solar cell. The investigations were focused on the modification of typical screen printing fabrication of the thin electrical finger paths of the front solar cell electrode. The resulting contacts were characterized morphologically (the dimensions and geometry of the front contacts) by scanning electron microscopy. The composition of finger path covered with copper was analyzed using energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

Findings

In this work, the front electrodes were screen printed with the use of conventional silver-paste on a p-type Cz–Si-textured wafer with a n+ emitter and with an antireflection coating. After that, the fired front electrode was electroless coated with copper. The electroless copper deposition was performed in two stages. First, the surface of the photovoltaic cell was dipped in an aqueous solution of CuSO4 and then dried in air at room temperature. When the surface dried, the cell was immersed in hydrogen fluoride solution (5 per cent) for 1 s followed by rinsing in deionization water.

Originality/value

The experiments confirmed the potential application of copper as an additional layer of the solar cell front metal electrode. On the one hand, this process is very simple and, on the other, the authors demonstrate a problem with the mechanical stability of the covered paths leading to electrode delamination.

Details

Circuit World, vol. 41 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 3 August 2015

Kazimierz Drabczyk, Jaroslaw Domaradzki, Piotr Panek and Danuta Kaczmarek

The purpose of this paper was the investigation of transparent conducting oxide (TCO) applied as an additional part of front metal electrode of crystalline silicon solar cell…

Abstract

Purpose

The purpose of this paper was the investigation of transparent conducting oxide (TCO) applied as an additional part of front metal electrode of crystalline silicon solar cell. Transparent conducting oxides are widely used as counter electrodes in a wide range of electronics and optoelectronics applications, e.g. flat panel displays. The most important optical and electrical requirements for TCOs are high optical transmittance and low resistivity. This low resistivity might invoke the possibility of increasing the distance between the fingers in the solar cell front electrode, thus decreasing the total area covered by metal and decreasing the shadowing loss.

Design/methodology/approach

In the present work, thin films of indium-tin-oxide (ITO) as a transparent counter electrodes, were evaporated on the surface of silicon n+-p junction structures used in solar cells. The influence of the properties of ITO electrode on the electrical performance of prepared solar cells was investigated through optical and electrical measurements. The discussion on the influence of deposition conditions of the TCO films on recombination of the photogenerated electrical charge carriers and solar cell series resistance was also included.

Findings

In this work, the fingers lines 100 μm width were screen-printed on the c-Si wafer with ITO layer. Monocrystalline silicon 25 cm 2,200-μm-thick wafers, were used for this testing. The usefulness of the ITO films as antireflection coating was discussed as well. It is commonly known that electrical performance of solar cells is limited by surface passivation. Despite this, the obtained results for ITO-Si structures showed relatively high value of short circuit current density (Jsc) up to 33 mA/cm2.

Originality/value

Our experiments confirmed the potential of application of ITO as anti-reflection coating (ARC) layer and according to their low resistivity possible use as a functional counter electrodes in photovoltaic structures.

Details

Microelectronics International, vol. 32 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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