Transmissible Laser Energy for Light Integrated Energy Storage Systems

NSF TNSCORE REU NSF EPS-1004083

Ashton Davis, Thomas Metke, Andrew Westover, Adam Cohn, Cary L. Pint

Testing of Laser

Future Work

Objective

This poster is based upon work to be published: T. Metke, A. Westover, R. Carter, S. Chatterjee, L. Oakes, W. Erwin, R. Bardhan, J. Mares, S. Weiss, and C.L. Pint, “Efficient water desalination using surface engineered porous silicon,” (in preparation for submission).

Results/Conclusion

References and Acknowledgements • Kawashima, Nobuki, and Kazuya Takeda. "Laser Energy Transmission for a Wireless Energy

Supply to Robots." : 10. InTech. Web. 3 July 2014.

• Raible, Daniel, Dinca Dragos, and Taysir Nayfeh. "Optical Frequency Optimization of a High

Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells." : 15. Web. 12 June

2014.

• Direct integration of a supercapacitor into the backside of a silicon photovoltaic

deviceWestover, Andrew S. and Share, Keith and Carter, Rachel and Cohn, Adam P. and

Oakes, Landon and Pint, Cary L., Applied Physics Letters, 104, 213905 (2014),

DOI:http://dx.doi.org/10.1063/1.4880211

I would like to thank the National Science Foundation, the Pint laboratory and the Vanderbilt

Institute of Nanoscale Science and Engineering for the opportunity to do this research.

Introduction and Background

Methods

Testing of Supercapacitor

Cyclic Voltammetry Charge-Discharge

Each and everyday people need more and more sources of energy. Imagine being able to charge your phone within seconds and not being anywhere near an outlet. This project combines solar cells and pseudocapacitors, to make efficient energy storage that can be used quickly and remotely charged. By using a laser to charge this device, wireless remote energy transfers are going to soon be the new method of charging.

First we tested commercially available polycrystalline silicon solar cells with different lasers. Below we show the data obtained using the 532nm 28mW Handheld Laser.

Solar Cell

Profile of Porous

Silicon (Side View)

Back Electrode

Starting with a cheap commercially available polycrystalline silicon solar cell 1. Etched nanopores onto the back of the solar cell

to create a high surface area electrode for energy storage, and paired this with a porous silicon back electrode.

2. Deposited polyanalline on porous silicon to provide pseudocapacitance.

3. We used a 1M H2SO4 electrolyte and a polymer separator between the electrodes.

• Buy higher performing solar cells such as GaAs. • Develop a solid state electrolyte • Buy lasers that are better suited for our solar cells.

PANI on porous back of solar cell

This project demonstrated initial proof of concept that an energy storage can be created on a solar cell. Furthermore this device can be coupled with a laser for remote charging. This is the data that was able to be collected from the testing. : • The device could store energy up to 560 μWh/m2

• Design and test a solar cell/pseudocapacitor combination device that can be remotely charged using a laser.

200 nm

Top View of Porous

Silicon

PANI

Porous Silicon

1M H₂SO₄

0.0 0.1 0.2 0.3 0.4 0.5 0.6

0

1

2

3

4

5

6

Cu

rre

nt

(mA

)

Voltage (V)

0.0 0.1 0.2 0.3 0.4 0.5 0.6

0.0

0.5

1.0

1.5

2.0

2.5

Po

wer

(mW

)

Voltage (V)

Voc:

0.55V

Jsc:

5.2 mA

Max Power:

2.1 mW

• Power Efficiency: 7.7% • Quantum Efficiency: 44%

-2 0 2 4 6 8 10 12 14 16 18

0.1

0.2

0.3

0.4

0.5

0.6

Vo

lta

ge

(V

)

Time (s)

0.0 0.2 0.4 0.6 0.8 1.0

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Oxidation

Cu

rre

nt

(mA

)

Voltage (V)

Reduction100mV/s Current Density:

.1mA/cm2