Objective
TOGETHER WITH THREE OTHER EUROPEAN TEAMS, WE AIM AT PROVING THE FEASIBILITY OF EFFICIENT (12%) SOLAR CELLS ON CHEAP (1$/WP) CRYSTALLINE SI SUBSTRATES.
The 3 main aspects of this work were the simulation and optimisation of epitaxial cells, the building and study of the cells, and the improvement of the initial upgraded metallurgical grade (UMG) silicon.
Using several kinds of UMG polycrystals as substrates, we succeeded in making epitaxial cells with an efficiency between 11.5 and 12 %. Including the expected improvement of the emitter, the efficiency should surpass 12 %. Apart from the intermediate steps involved in epilayer growth, which remains the weak stage of the process economically, this technology is a simple and cheap one, because impure raw materials are used to grow the ingots and because an integral screen printing technology is used to complete the cells.
THE TECHNICAL GOAL OF THE CONTRACT, WHICH WAS TO OBTAIN A CONVERSION EFFICIENCY OF 12% FOR EPITAXIAL CELLS GROWN ON UMG-SI SUBSTRATES, HAS BEEN REACHED. IN COOPERATION WITH M.CAYMAX (IMEC-LEUVEN), WE HAVE IN A FIRST STEP BUILT EPITAXIAL CELLS ON WAFERS CUT FROM DIFFERENT INGOTS FROM CNRS-VITRY, CGE, ITALSOLAR AND PHOTOWATT, AND OBTAINED THE FOLLOWING EFFICIENCIES: MAXIMUM EFFICIENCY WAS 11.7% AND 12.5% FOR A REFERENCE MONOCRYSTALLINE EPITAXIAL CELL. THESE RESULTS WERE OBTAINED USING THE SOLPRO CELL TECHNOLOGY, WHICH LEADS TO A RATHER DEEP P-N JUNCTION: AS A RESULT THE BLUE EFFICIENCY IS LOW AND MIGHT BE USING THE TECHNOLOGY DECELOPED LAST YEAR AT IMEC. THE COMPARISON WITH THE SIMULATED CURVES CALCULATED LAST YEAR SHOWS THAT THE EPILAYER DIFFUSION LENGTH LN IS LARGER THAN 100 MICRO M, A VERY GOOD VALUE WHICH EXPLAINS THE HIGH EFFICIENCY REACHED. THIS WORK CONFIRMS THAT FOR THIS TYPE OF CELLS THE SUBSTRATE SHOULD BE HIGHLY DOPED (0.02 - 0.06 OHMCM), AS EXPECTED THEORETICALLY. THE STUDY OF THE OPEN CIRCUIT VOLTAGE ALSO CONFIRMS THE BENEFICIAL INFLUENCE OF THE BACK SURFACE FIELD AT THE SUBSTRATE/EPILAYER INTERFACE. IN A SECOND STEP, THESE RESULTS HAVE BEEN STILL IMPROVED BY TEXTURIZING THE BACK AND FRONT SURFACE OF THE WAFER IN A NAOH-KOH MIXTURE: AN EFFICIENCY OF 12% WAS REACHED. THIS WORK WAS MAINLY THE TASK OF LE HOANG THI TO AND LE QUANG NAM. ANOTHER PIECE OF WORK HAS BEEN THE TASK OF B. KAYALI AND R. SURYANARAYANAN; IT CONSISTS OF PREPARING ALTERNATIVE SUBSTRATES BY A PLASMA TORCH TECHNIQUE. THIS TECHNIQUE HAS BEEN MODELLIZED. ALSO, FROM A WACKER POWDER, WE HAVE BEEN ABLE TO OBTAIN A NUMBER OF WAFERS REACHING 5X5CM2 IN DIMENSIONS. THESE WAFERS ARE FAGILE (MICROCRACKS, HOLES) BUT THEIR ELECTRICAL QUALITY IS GOOD AND MAY STILL BE INCREASED BY AN EPILAYER DEPOSITION (LN > 60 MICRO M). AT THIS STAGE, NO SOLAR CELL COULD BE MADE ON SUCH WAFERS, DUE TO THE MICRO-HOLES THAT BRING SHORT CIRCUITS.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
- natural sciences chemical sciences inorganic chemistry metalloids
- medical and health sciences medical biotechnology cells technologies
You need to log in or register to use this function
Programme(s)
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Topic(s)
Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Data not available
Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Call for proposal
Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
Data not available
Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
Funding Scheme
Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Coordinator
92195 Meudon
France
The total costs incurred by this organisation to participate in the project, including direct and indirect costs. This amount is a subset of the overall project budget.