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Mojrova B.,Brno University of Technology | Buck T.,International Solar Energy Research Center Konstanz
NANOCON 2015 - 7th International Conference on Nanomaterials - Research and Application, Conference Proceedings | Year: 2015

Contact formation is one of the significant steps, which have to be optimized in the production of silicon solar cells with high efficiency based on N-type substrates. In this work a comparison of the effect of various sintering conditions on the contact formation process was done. Contacts were screen printed on passivated boron doped P+ emitters using two pastes for front-side metallization from different producers. Two different temperature profiles were compared at an atmospheric concentration of O2. The influence of the O2 concentration on resistance was investigated for one profile. Resistance changes during firing were measured simultaneously with the temperature using Rapid Thermal Processes (RTP) modified to in-situ resistance measurement.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2013.6.4 | Award Amount: 4.27M | Year: 2013

When considering renewable energy sources, like solar electricity, people often do not directly see the benefit of their investment. While the sun is shining and might be producing electricity in their homes, they are at their work and cannot use that energy directly, while when they need the energy at night (for laundry, lighting, computers) the solar panel is no longer producing. Indeed, research has shown that while in theory houses can be self-reliant on solar panels by the amount of electricity they produce, it would require considerable (and expensive) storage capacity to realize this.
With smart management and control systems, different types of buildings (for instance a mix of houses, companies and schools) could be connected in such a way that this neighbourhood would use more, or even most, of its renewable energy within the community. For example, if one neighbour does not use her electric car one day, its battery can be used to store excess energy produced from the solar panels on another neighbours roof.
The CoSSMic project aims to develop the ICT tools needed to facilitate this sharing of renewable energy within a neighbourhood, and will show the feasibility of its concept in two different areas: Konstanz in Germany and the Province of Caserta in Italy. At these trial locations, which are rather different in terms of population, sun, andavailable equipment, CoSSMic will investigate how to motivate people to participate in acquiring (more) renewable energy and the sharing of renewable energy in the neighbourhood, and test methods for making money with these schemes.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2009.3.8 | Award Amount: 3.19M | Year: 2010

The LIMA project exploits cutting edge photonic technologies to enhance silicon solar cell efficiencies with new concepts in nanostructured materials. It proposes nano-structured surface layers designed to increase light absorption in the solar cell while decreasing surface and interface recombination loss. Integration in a back contact design further reduces these interface losses and avoids shading.\nThe project improves light-matter interaction by the use a surface plasmonic nanoparticle layer. This reduces reflection and efficiently couples incident radiation into the solar cell where it is trapped by internal reflection.\nSurface and interface recombination are minimised by using silicon quantum dot superlattices in a passivating matrix. The distance between quantum dots ensures wave-function overlap and good conductivity. An effective field at the superlattice - crystalline silicon interface ensures that the cell is insensitive to the recombination velocity at this heterojunction, and further increases the collection probability in the quantum dot layer.\nThe dots allow a fundamental efficiency enhancement due to experimentally confirmed multiple exciton generation. This mechanism increases photocurrent and can in theory raise the theoretical single junction efficiency limit from 33% to 44%.\nThese surface plasmonic and quantum dot layers are integrated in a high efficiency crystalline silicon back contact cell. This is designed such that the space charge region is separated from the superlattice crystalline silicon heterojunction minimising non radiative space-charge recombination. The back contacts and dielectric electrical insulator are designed to maximise back surface reflection and enhance the light trapping of incident radiation without shading losses.\nThe project combines expertise between academic and industrial partners. The goal is a high efficiency cell using novel concepts to enhance proven cell designs.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ENERGY.2013.2.1.1 | Award Amount: 10.26M | Year: 2013

The European photovoltaics PV market still represents the predominant share of worldwide installations and electricity generated from PV is becoming increasingly competitive, with an average levelized cost of energy (LCOE) estimated to be between 0.100.16 /kWh in 2011 . This constant reduction of LCOE means that the European industry can only regain its competitiveness with (i) a concomitant reduction of production and investment costs (current net price level ~0.81.0 /Wp today) in Europe in order to face the strong price competition of emerging countries (China and Taiwan), (ii) investment in novel advanced industrial processes allowing for high efficiencies and low-cost device production (iii) the development of high-end tools and processes which are more difficult to master and duplicate, securing a technology leadership. These conditions are necessary to ensure sustainable PV technology production in Europe and the construction of a robust European PV industry able to beat international competition. However, ultra-high-efficiency PV devices require manufacturing processes that are increasingly complex, which results in an increase in the related investment and fabrication costs. Given that the market still requires a reduction of the technology price, we are left with a paradox, and we must find ways to produce high-efficiency devices with competitive industrial processes. The concept proposed by the HERCULES project is to develop innovative n-type monocrystalline c-Si device structures based on back-contact solar cells with alternative junction formation, as well as related structures including hybrid concepts (homo-heterojunction). These concepts are the most promising technologies to reach ultra-high efficiencies with industrially relevant processes. The HERCULES strategy is to transfer the developed processes to the industrial scale by considering all major cost drivers of the entire manufacturing process chain of modules.

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: NMP-2008-2.5-2 | Award Amount: 4.55M | Year: 2009

The resistance at the metal contact-semiconductor interface and recombination at the passivating layer-semiconductor interface are two important bottlenecks for improving the performance of current solar cells. These processes are quantum mechanical by nature, but so far most studies and attempts to improve the properties of solar cells have been at the device scale. A main reason for this is the great challenges faced by theoretical modelling. Accurate descriptions of the geometric and electronic structures are required, which necessitate the use of highly sophisticated methodologies based on first principles. At the same time, the interfaces extend in many cases well beyond the size limit of first principles methods, creating the need for more efficient methods, which can operate at larger time and size scales. HiperSol aims to fill this knowledge gap by developing and implementing a multi-scale modelling environment. The physics at the various scales will be treated by a multitude of techniques, and the boundaries between these techniques are of utmost importance for the success of this project. Hence, considerable emphasis will be laid on integrating different methods seamlessly and consistently, with many possibilities to update and improve the different tools. An important development will be the implementation of semi-empirical pseudo-potentials, which can calculate the accurate electronic structure of large structures with up to millions of non-equivalent atoms as well as methods for calculating the lifetime of charge carriers. The multi-scale environment will involve construction of reliable inter-atomic potentials for empirical molecular dynamics, providing input to first principles calculations that in a following stage will be integrated into finite element method (FEM) calculations, reaching the size and time scales of real devices. The modelling will focus on real interfaces and be used to investigate enhancements to present solar cell technology.

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