A Review of Photovoltaic Cells (David Toub)

A Review of Photovoltaic Cells

David Toub ECE42312/16/06

Agenda

• Introduction

• Functionality

• Semiconductor Properties

• VTC

• Efficiency and PV Design

• Auxiliary Design

• Applications

• Research

• Conclusions

Introduction

• Clean Energy

• PV System

– Cells

– Energy storage

– Charge Controller

– AC/DC converter

•Ventre, Gerard. Messenger, Roger A. Ventre, Jerry. Photovoltaic Systems Engineering. CRC Press Technology and Industrial. 2004

Functionality

• pn diode

• No illumination– Diode behavior– e, h separated

• Illumination– Incident photons create e-h pairs– E fielde-h pairs separate

•Photovoltaics.” Wikipeda, The Free Encyclopedia. Downloaded from www.wikipedia.org on 12/02/06.

Semiconductor

• Absolute 0 Perfect insulator

• Temp increases conduction increases

• External energy raises temperature

•Ventre, Gerard. Messenger, Roger A. Ventre, Jerry. Photovoltaic Systems Engineering. CRC Press Technology and Industrial. 2004

VTC

• Performance Limits

• Pm = Vmax x Imax

• Incorporate load

•Ventre, Gerard. Messenger, Roger A. Ventre, Jerry. Photovoltaic Systems Engineering. CRC Press Technology and Industrial. 2004

Energy Conversion Efficiency

• η =Pm/(E x Ac)• Primary Challenge• Incident photons

– Ep<Ebg Elost

– Ep>Ebg Ee- + Elost

– Ep=Ebg Ee-

• Silicon tradeoff– High bg loss– Low bg E, V reduced– Optimal at bg=1.4eV

Loss Tradeoffs

• Cell Top – Must be transparent– Too thin bad conduction

• Cell Interior grid– Large grid helps e-’s– Large grid blocks photons

Auxiliary Design

• Heavy modules– structural stress– Wind tension

• Pollution• Fan Example

– Speed– Acceleration– Without illumination

• E/V Ah

Applications

• Electric grid extensions not offered • Clean• Solar powered house• Water pumping systems• Garden lights• Automobiles• Source utility grid• Satellites, shuttles

•Ventre, Gerard. Messenger, Roger A. Ventre, Jerry. Photovoltaic Systems Engineering. CRC Press Technology and Industrial. 2004

Research

• Thin Film– Cheap– Increased unit loss– Multilayer Efficiency

• Nanocrystalline– Thin film + mesoporous MO– Increased internal reflection– Great efficiency expensive

Conclusions

• Environmentally benign

• Inefficient uncommon Still fuel

• Future Efficiency increasing Cheaper

References• Ventre, Gerard. Messenger, Roger A. Ventre, Jerry. Photovoltaic Systems Engineering. CRC Press

Technology and Industrial. 2004• F Lasnier. Photovoltaic Engineering Handbook TG Ang - 1990 - A. Hilger New York• “Two layer organic Photovoltaic Cell.” -- Volume 48, Issue 2, pp. 183-185 Research Laboratories,

Eastman Kodak Company, Rochester, New York. Applied Physics Letters -- January 13, 1986• Harmon, C. “Experience Curves of Photovoltaic Technology.” IIASA Publications. 2000.• “Photovoltaics.” Wikipeda, The Free Encyclopedia. Downloaded from www.wikipedia.org on

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