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Nanostructured Photovoltaic Cells Fabricated with PAO (Porous Aluminum Oxide) Templates

Lin Li(Mechanical Engineering)

Santa Barbara City CollegeLab Mentor: Martin SchierhornFaculty Advisors: Galen D. Stucky

Martin Moskovits

Department of Chemistry & Biochemistry, UCSBFunding: The Institute for Collaborative

Biotechnologies (ICB)

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Application of Nanostructured Photovoltaic Cells Fabricated with PAO Templates

1. Energy Source: solar power (free and renewable)

2. Development of Materials: flexible, cost-effective, easily processable (such as polymers)

(Interface of two different materials)

•The diagram of the nanostructured photovoltaic cells

Photons

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Procedure of Making CdSe Cells

1

5

2 3

64

VV

PAO

Metal layer

CdSe Nanorods

Copper Strip

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Goals

Find optimal thickness of TiO2

Try out different metal layers instead of gold(Ti or Ni)

Play around with different dimensions of nanorodes

Increase the absorption of photons

decreased recombination kinetics

limit the Schottky barrierissues

1

5

2 3

64

VV

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Preparation of PAO Templates

• First Anodization

1. Condition:--- 0.3 M oxalic acid --- 15 degree C --- 40 Volts for 3 hours

2. Removed with H3PO4 / H2CrO4 at 65 degree C for 2 hours (in the oven)

• Second Anodization

1. Same conditions for 12 hours --- results: pores of ~80

micrometers long by ~40 nm in diameter

Template after 2nd Anodization

1 2

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CdSe Nanorods under the SEM

CdSe nanorods

TiO2 layer

Metal layer(ITO layer)

1

5

2 3

64

VV

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Electrochemical Photovoltaic Characteristics of CdSe

CdSe samples

Efficiency = ( Voc * Isc * FF )( 100mW/cm2 )

• Voc – open circuit voltage• Isc – short circuit current• FF – fill factor

KeithleySMU

Equipment for testing

-0.3 -0.2 -0.1 0.0-15.0µ

-10.0µ

-5.0µ

0.0

5.0µ

10.0µ

15.0µ

Cur

rent

(A)

Potential (V) vs. Pt

with TiO2 + Au Au with TiO2 + ITO

IV characteristics

Voc

Isc

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Summary

• Conclusions

1. IV Curve shows that TiO2 layer leads to better efficiency than the one without it

2. TiO2 layer decreases recombination kinetics

• Future Plans

1. Combine P3HT polymer with CdSe half solar cells

2. Substitute with new polymers• Picture comes from:www.bee.qut.edu.au/.../projects/photovoltaics

P3HTpolymer

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Acknowledgements

• Mentor: Martin Schierhorn

• Adviser: Galen D. StuckyMartin Moskovits

• Professors: Nick Arnold & Dr. Young

• Funding Source: The Institute for Collaborative Biotechnologies (ICB)

• Summer research program: INSET

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THANK YOU !

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Diagrams of Anodization

Equipment for Anodization

0 2 4 6 8 10 120

2

4

6

8

10

12

14

16

18

0.10

0.11

0.12

0.13

Cur

rent

(A)

Tem

pera

ture

(C)

time (h)

Temp

2nd Anodization 5_16

current

Time vs. Temperature & Time vs. Current

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PAO Templates

(With gold layer)(With ITO layer)

• PAO Templates