THE EFFECTS OF HARSH ENVIRONMENTS

ON SOLAR CELLS

Laura Bruce, Brian Dawes, James Horner, Krupa Patel, Ronak Patel, Nicholas Porto,

Steven Scarfone, Olivia Shabash, Priyanka Shah, Daphne Sun, Jisoo Yoon

 Advisor: Dr. Paul V. Quinn Sr.

Teaching Assistant: Sally J. Warner

NASA Strives for Efficient Solar Cells

NASA interested in decay of cells

Solar Cells in Space

Variables tested include: Light intensity Wavelength Environmental factors such as radiation, heat, and freezing

Conditions in Space

Average temp: 2.725 Kelvin (-455˚F)

Sunlight temp: 393 Kelvin (248˚F)

Radiation affects cells

The Photoelectric Effect Generates current

Increasing light

frequency increases electron energy

Increasing electron energy increases current

h = Planck’s constantf = frequency Eph = photon energyK = electron energyφ = work function

Doping Silicon

Primary material

Diamond FCC crystalline structure

Doped with boron and

phosphorous atoms

Doping Silicon

N-Type P-Type

How Solar Cells Work

Apparatus

BaselineSix light bulbs used to create baseline:

65 Watts

Comparing Wavelengths of Light

0

0.5

1

1.5

2

2.5

3

3.5

0 0.2 0.4 0.6 0.8 1

Volt

age

(mV)

Percent Intensity

Voltage vs. Intensity

Blue Bulb 50 W

White Bulb 25 W

Clear Bulb 75 W

Yellow Bulb 25 W

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 1 2 3 4

Curr

ent (

mA

)

Voltage (mV)

IV Curve

Blue Bulb 50 W

White Bulb 25 W

Clear Bulb 75 W

Yellow Bulb 25 W

Comparing Different Intensities

00.5

11.5

22.5

33.5

44.5

0 0.2 0.4 0.6 0.8 1

Volta

ge (m

V)

Percent Intensity

Voltage vs. Intensity

Blue Bulb 50 W

Blue Bulb 65 W

Blue Bulb 150 W

0

0.5

1

1.5

2

2.5

0 1 2 3 4 5

Curr

ent (

mA)

Voltage (mV)

IV Curve

Blue Bulb 50 W

Blue Bulb 65 W

Blue Bulb 150 W

Liquid nitrogen exists at

77.2 Kelvin (-320.7°F)

Freezing Solar Cells

Effects of Freezing

0

1

2

3

4

5

6

7

8

9

0 0.2 0.4 0.6 0.8 1

Volt

age

(mV)

Percent Intensity

Voltage vs. Intensity (Cell A)

Baseline

1st freezing

2nd freezing

3rd freezing

4th freezing

Effects of Freezing

0

1

2

3

4

5

6

7

0 0.2 0.4 0.6 0.8 1

Volt

age

(mV)

Percent Intensity

Voltage vs. Intensity (Cell B)

Baseline

1st Freezing

2nd Freezing

3rd Freezing

Heating Solar Cells

Avg. temp. of object in sunlight: 248°F

Highest temp. metals reach in space: 500°F

Effects of Heating

Testing Radiation

100 microcurie strontium-90 placed on

solar cell

Cells exposed to beta decay (electrons)

Effects of Radiation

0

2

4

6

8

10

12

0 0.2 0.4 0.6 0.8 1

Volt

age

(mV)

Percent Intensity

Voltage vs. Intensity

Baseline Blue Bulb 150 WAfter Radiation

0

1

2

3

4

5

6

7

8

0 2 4 6 8 10 12

Curr

ent (

mA)

Voltage (mV)

IV Curve

Baseline Blue Bulb 150 WAfter Radiation

Normal solar cell

SEM Imaging

Frozen solar cell

Heated solar cell

SEM Imaging

Normal solar cell

Factors that Affect Outcome

Resistance of voltmeters

Extraneous light sources

Overheating Other damage

Conclusion

Blue Light optimum source 150 W optimum intensity Heating destroys cells Freezing may improve

performance Radiation alters cell

performance Framework for future

experimentation

Acknowledgments

Advisors Dr. Paul Quinn Sally Warner

Liquid Nitrogen Supplier Dr. Ryan Z. Hinrichs

Directors Dr. Miyamoto Dr. Surace

AcknowledgmentsThank you to all of our sponsors!

John and Laura OverdeckThe Ena Zucchi Trust Johnson and Johnson Jewish Communal Fund Bristol-Myers Squibb Bayer HealthCare The Crimmins Family Charitable Foundation Novartis The Edward W. and Stella C. Van Houten Memorial Fund Roche Independent College Fund of New Jersey Corporate Matching Gifts: Alliance Bernstein, AT&T Foundation,

Direct Edge, Goldman, Sachs, and Company, Met Life, Microsoft Corporation, Network for Good

NJGSS Alumnae and Parents 1984 - 2009

Questions?