Photovoltaics

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Photovoltaics research challenge
David Infield CREST (Centre for Renewable Energy
Systems Technology) Department of Electronic and
Electrical Engineering Loughborough
University Address to Finnish Symposium Energy
Issues A Challenge for Physics Helsinki, August
31st 2007
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Structure of Talk

• Background PV technology and markets
• Research priorities
• Research examples
• New hybrid thin film photovoltaic cell
• Assessment of thin film quality and performance
• Conclusions

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Solar Home Systems
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Domestic Grid Connected
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Building Integrated PV (BIPV)
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Other BIPV Systems
West Oxfordshire District Council Offices, UK
The Welsh Optics Centre
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Large Field Arrays
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Market Growth
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Manufacturers Worldwide
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Falling PV Costs
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Improving Reliability
Source IEA-PVPS Task 2 PV-Systems Performance
Database
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Improving Performance
Source IEA-PVPS Task 2 PV-Systems Performance
Database
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Record Efficiencies
Cell and module efficiencies under Standard Test
Conditions The modules are from the material
CIGSS( Cu(InGa)SSe) This is a triple junction
a-Si /a-Si/a-SiGe 6.5 efficiency is
reported for the organic tandem solar cells
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Progress with Thin Film PV
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Record 14 Efficiency for Flexible CIGS Solar
Cells on Plastic
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Record 11.4 Efficiency for Monolithic CdTe Solar
Cells on Plastic
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Overall Research Challenge
To improve PV device performance and durability
and to substantially reduce the cost of
electricity from PV. This requires better
devices and new low cost bulk manufacturing
techniques.
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PV Research Topics Considered

• crystalline wafer silicon PV
• thin film PV
• Common thin film PV research issues
• CadmiumTelluride solar cells
• Copper Indium Gallium Diselenide solar cells
• Thin film Silicon
• advanced PV concepts
• Excitonic devices
• Quantum wells and dots
• Concentrator PV systems
• balance of systems issues to include all other
  relevant aspects including building integration

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Research Priorities Crystalline wafer silicon


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Thin film cells



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Excitonic devices




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Quantum wells and dots





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PV system aspects






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New CIGS-Dye Cell Hybrid
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New Device Structure
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Measured Performance
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Individual Cell I-V Curves
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I-V Curve for Tandem
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Large Scale LBIC for Quality Control
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Cell Performance Variation
.

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Different Defect Types
.

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Conclusions

• PV technology and markets are developing fast
• But costs remain high and there is a need for
  focussed RD on
• Improvements to existing devices with emphasis on
  new low cost manufacturing techniques and
  production quality control
• New devices based on polymers and quantum dots