MPO Energy

Averton, France

MPO Energy

Averton, France
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Landis S.,CEA Grenoble | Pirot M.,French National Solar Energy Institute | Monna R.,French National Solar Energy Institute | Lee Y.,CEA Grenoble | And 4 more authors.
Microelectronic Engineering | Year: 2013

A large scale patterning processes to produce patterned silicon surfaces with low reflectivity were developed for silicon solar cells. Optical design, sample manufacturing, optical characterizations and cell efficiency measurements were conducted. Optical simulations were carried out to compute the reflectivity of the patterned surface to target the optimum shape to be manufactured in the silicon substrate. Patterned surfaces were manufactured using thermal Nano Imprint Lithography over 125 125 mm2 Si-c and Simc wafer and proportional dry etching. A high aspect ratio inverted pyramid shapes were achieved in both Si-c &Si-mc substrates. An effective reflectivity (Rw) of about 3% was achieved on multi-crystalline silicon with the inverted pyramid pattern. The patterning process uniformity over the substrate was better than 97%. I(V) measurements of standard Si-mc KOH textured and Si-mc inverted pyramidal textured using Nano imprint and dry etching revealed that a drop of about 3% were induced in the open-circuit voltage, a drop of about 3.4% for the fill factor, however with an increase of about 8.3% for the short-circuit current. A gain of 0.33% absolute efficiency is obtained on the Si-mc Nano-imprinted cell compared to the KOH textured Si-mc cell. The gain of the short-circuit current is directly connected to the gain of reflectivity (8%) obtained on the finished solar cell. © 2013 Elsevier B.V. All rights reserved.

Thibert S.,MPO Energy | Thibert S.,University Grenoble Alpes | Thibert S.,French National Center for Scientific Research | Jourdan J.,MPO Energy | And 4 more authors.
IEEE Journal of Photovoltaics | Year: 2015

A cooptimization procedure has been developed for industrial solar cells metalized using a nickel seed layer thickened by a plated silver layer. A theoretical contact resistivity model for NiSi nickel silicide contacts was first computed and inserted into classical power loss equations. Optical, resistive, and recombination losses were then simulated with a standard set of parameters used in production. This procedure allows the generation of efficiency and silver consumption contour plots for homogeneous and selective emitters. For both, general guidelines are given for the optimization of the doping profile, the finger spacing, and the finger thickness. © 2011-2012 IEEE.

Thibert S.,MPO Energy | Thibert S.,University Grenoble Alpes | Thibert S.,Grenoble Institute of Technology | Jourdan J.,MPO Energy | And 8 more authors.
Progress in Photovoltaics: Research and Applications | Year: 2016

A commercially available silver paste was modified to match the flexographic process requirements. Rotational and oscillatory rheological tests were carried out to assess the printability and spreading behaviour of the resulting inks. Then, a multifactorial approach was used on a laboratory-scale printing press to adapt the flexographic process for the front side metallisation of Cz-Si solar cells, especially for the seed layer deposit of two layer contacts. To quickly identify the significant process parameters, a fractional design of experiment based on a screening approach at two levels was performed. Afterwards, two full factorial designs of experiments were implemented. While the first one allows a better understanding of the effect of the main factors and interactions, the second allows a fine tuning and a confirmation of the first results. Additionally, this methodology allows corroborating the influence of the ink rheological properties on the printing results. Following the process study and optimisation, a seed layer with an average width of 25 μm was printed at a high 0.3 m/s throughput. Additional results suggest that the line width and the throughput can be further improved, which underlines the potential of flexography for photovoltaic applications. Finally, the light-induced process was used to thicken the seed layer after a standard firing-through step, leading to an encouraging 17.9% efficiency on Cz-Si solar cells. © Copyright 2015 John Wiley & Sons, Ltd.

Bounaas L.,French National Solar Energy Institute | Auriac N.,French National Solar Energy Institute | Grange B.,French National Solar Energy Institute | Monna R.,French National Solar Energy Institute | And 6 more authors.
Energy Procedia | Year: 2013

Dielectric back passivated solar cells with local Al-BSF (Back Surface Field) are investigated to lead the way on achieving higher efficiencies. However the formation of efficient and uniform local BSF needs a proper opening of the dielectric passivation layers. In this paper the laser ablation mechanisms with green and ultraviolet laser sources are studied to locally remove dielectric stacks such as SiO2/SiNx. Green laser process parameters are found to lower silicon surface damages but highlight the importance of using a post-laser cleaning step based on an alkaline etching solution. The impact of this additional step on BSF formation is studied by extracting the local internal quantum efficiency from LBIC mappings of a fabricated PERC solar cell. © 2013 The Authors.

Bounaas L.,French National Solar Energy Institute | Auriac N.,French National Solar Energy Institute | Grange B.,French National Solar Energy Institute | Jourdan J.,MPO Energy | And 5 more authors.
Energy Procedia | Year: 2012

This paper presents a detailed analysis of point-contacted aluminium rear side for silicon solar cells. An industrial feasible process for these solar cells based on screen-printed aluminium layer and thermal oxide/silicon nitride passivation is described. The local removal of the passivation stack by the mean of laser ablation is studied. Laser conditions are found to selectively and locally ablate the layers and reduce the laser-induced damages in the Si and the passivation layer. Results of these studies are applied on large area back passivated solar cells and electrical parameters highlight the importance of parasitic shunting on this type of structure.

Thibert S.,MPO Energy | Thibert S.,French National Center for Scientific Research | Jourdan J.,MPO Energy | Bechevet B.,MPO Energy | And 3 more authors.
Materials Science in Semiconductor Processing | Year: 2014

Four commercially available silver pastes for silicon solar cells front side metallization were examined and compared. Both rheological and printing experiments were used to correlate pastes properties and screens characteristics with printing results. Theoretical printability and spreading behavior were first characterized by means of rotational and oscillatory rheological experiments. Further on, the pastes were printed, dried, and fired in a standard solar cell process on an industrial line using a full factorial design of experiments. This methodology allows to study the effect of the paste, the screen, the aperture, and their interactions on the printing results. Especially, the finger aspect ratio, the finger cross section and its relative standard deviation, which are respectively linked to solar cell efficiency, silver consumption, and process stability, were systematically measured. This work allows finding general guidelines for process optimization. Finally, a confirmation test was carried out, leading to 19% efficiency on monocrystalline silicon solar cells in an industrial environment. © 2014 Elsevier Ltd. All rights reserved.

Thibert S.,MPO Energy | Thibert S.,Grenoble Institute of Technology | Jourdan J.,MPO Energy | Bechevet B.,MPO Energy | And 3 more authors.
Conference Record of the IEEE Photovoltaic Specialists Conference | Year: 2013

With the recent introduction of ion implantation in the photovoltaic industry, it is now easier to carefully tailor the emitter doping profile. However the metallization layout should be optimized in the same time, as they are closely linked via the metal/silicon contact resistivity. In this work, an advanced co-optimization procedure allows finding out the influence of the Schottky barrier height on the metal grid design and the optimal doping profile. The theoretical electrical properties of a 2 × 2 cm2 ideal silicon solar cell are also computed for each optimal combination. According to this work, the maximal achievable efficiency decreases from 26.2 % to 25.3 % if the Schottky barrier height increases from 0.5 eV to 0.9 e V. © 2013 IEEE.

Thibert S.,Grenoble Institute of Technology | Chaussy D.,Grenoble Institute of Technology | Beneventi D.,Grenoble Institute of Technology | Reverdy-Bruas N.,Grenoble Institute of Technology | And 3 more authors.
Conference Record of the IEEE Photovoltaic Specialists Conference | Year: 2012

The metallization of silicon solar cells becomes more and more critical due to the recent soaring prices of silver. Flexographic printing can be used to deposit the seed layer in a "seed and plate" scheme to replace screen printing, classically employed in production lines but limited by its resolution. To develop the process, several inks prepared from standard screen printing paste were tested. First, different rheological experiments were performed. Then the different inks were printed on silicon solar cells and a correlation was pointed out between rheological properties and printing results. The present work demonstrates that flexography is a potential candidate to deposit silver seed layer with a width as low as 30 μm with a printing speed of 0.5 m/s. Moreover the importance of rheological experiments during a printing process development is underlined. © 2012 IEEE.

Thibert S.,MPO Energy | Thibert S.,Grenoble Institute of Technology | Jourdan J.,MPO Energy | Bechevet B.,MPO Energy | And 3 more authors.
Energy Procedia | Year: 2013

A unified model for the nickel-silicon theoretical contact resistivity was computed, using a 0.6 eV Schottky barrier height, and compared to recent experimental data. This model was subsequently inserted in a classical co-optimization procedure. Numerical simulations were combined with analytical power losses equations to find out the effect of homogeneous emitter doping profile on an ideal lab-scale silicon solar cell. According to this work, an optimized emitter for plated contacts on a 10 μm wide nickel seed layer should have a junction depth ranging from 0.5 to 4 μm and a surface doping from 4 × 1018 to 2 × 1019 cm-3. This broad range allows getting more than 25.5% and up to 25.9% theoretical efficiency on a 2 × 2 cm2 silicon solar cell metallized with 10 μm thick fingers. Finally, contour plots were also simulated using a larger Schottky barrier height in order to figure out the effect of the nickel silicide contact interface on solar cell properties. © 2013 The Authors.

Mpo Energy | Date: 2012-07-05

A method for texturing an active surface of a photovoltaic cell in single-crystal silicon or poly-crystal silicon includes depositing a resin on the active surface of the cell, texturing the resin on the active surface with geometric patterns, and texturing the active surface of the cell by eliminating the deposited resin. The depositing of the resin is preceded by pre-texturing the resin on a depositing tool. The texturing step of the resin on the active surface is simultaneous with the depositing of the resin on the active surface.

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