1938-2 workshop on nanoscience for solar energy conversion · workshop on nanoscience for solar...

1938-2

Workshop on Nanoscience for Solar Energy Conversion

Prashant KAMAT

27 - 29 October 2008

University of Notre DameDepartment of Chemistry

235 Radiation LaboratoryNotre Dame IN 46556-0579

USA

Quantum Dot Solar Cells: Semiconductor Nanocrystals As Light Harvesters

14 TW Challenge

Meeting the Energy Demand

PrashantPrashant V. V. KamatKamatDept Of Chemistry and Biochemistry and Dept Of Chemistry and Biochemistry and

Radiation LaboratoryRadiation LaboratoryDept. of Chemical & Dept. of Chemical & BiomolecularBiomolecular EngineeringEngineering

University of Notre Dame, Notre Dame, Indiana 46556University of Notre Dame, Notre Dame, Indiana 46556--05790579

Farming SolarBeyond Fossil Fuels

After OilAfter Oil

Support: US DOE (BES)Support: US DOE (BES)

Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters

http://www.nd.edu/~pkamat

www.solarsales.com.au

Meeting the Energy Demand

World Oil Production vs. Discovery Source: Dr. C.J. Campbell

“DRILL BABY DRILL”

Source:Wikipedia

Can we address the clean

energy challenge with

Nanotechnology?

PtAcceptor TiO2

e

Our Research Focus

Molecular linker

Donor

Photoinduced electron transfer in light harvesting systemsDonor- AcceptorSemiconductor-SensitizerSemiconductor-SemiconductorSemiconductor-Metal

CdSeTiO2

hν

e

ethanol products

hνe e

e

h hh

Ag

TiO2

ethanol products

hνe e

e

h hh

Ag

TiO2

ethanol products

hνe e

e

h hh

ethanol products

hνee ee

ee

hh hhhh

Ag

TiO2

hνhν

eeh

eeh

eeh

eeh

eeh

eeh

C60C60

C60

Quantum Dot Solar Cells

Tunable band edge Offers the possibility to harvest light energy over a wide range of visible-ir light with selectivity

Hot carrier injection from higher excited state (minimizing energy loss during thermalization of excited state)

Multiple carrier generation solar cells.Utilization of high energy photon to multiple electron-hole pairs

GlassITO

Aluminum

Redox or Hole Transport Layer

Metal

SemiconductorNanocrystals

GlassITO

Aluminum


Metal


GlassITO

Aluminum


Metal


Glass

ITOPEDOTAluminum

Active Polymer/Semiconductor Layer

Glass

ITOPEDOTAluminum


Glass

ITOPEDOTAluminum


CdSe

TiO2

OTE

hν

e

e h

h

hCdSe

TiO2

OTE

hν

e

e h

h

h

PtElectrolyte

Polymer Solar CellPolymer Polymer Solar CellSolar Cell

Quantum Dot Sensitized Solar CellQuantum Dot Quantum Dot Sensitized Solar CellSensitized Solar Cell

Metal Junction Solar Cell

Metal Metal Junction Junction Solar CellSolar Cell

ECB

EVB

EF

e

h

1. Semiconductor/metal Interface

Red

Ox

et

ht

VB

–

+

+

–CB

hν

Because of smaller dimensions charge separation and transport issues in nanostructure films need to be tackled

Metal/PbSeNC/Metal Sandwich Photovoltaic Cell

Luther et al Nano Lett., Vol 8, 2008, 3488

PbSe NC film, deposited vialayer-by-layer dip coating

Short-circuit photocurrent (>21 mA cm-2) by way of a Schottky junction

EQE of 55-65% in the visible and up to 25% in the infrared region

Power conversion efficiency of 2.1%.

Glass

ITO

Aluminum


Metal


Glass

ITO

Aluminum


Metal


Glass

ITO

Aluminum


Metal


2. Polymer –Semiconductor Nanocrystal Hybrids

Glass

ITOPEDOTAluminum


Glass

ITOPEDOTAluminum


Glass

ITOPEDOTAluminum


Adv. Mater, 2004, 16, 1009-1013

SCIENCE VOL 295, 2002 2425

Hybrid Nanorod-Polymer Solar CellsGlass

ITO

PEDOTAluminum


Glass

ITO

PEDOTAluminum


Glass

ITO

PEDOTAluminum


eh

eh

eh

eh

eh

e

h

e e ee e

ee

e

e

eh

h

eh

Red

OxTiO2

CdSe hν

eh

eh

eh

eh

eh

e

h

e e ee e

ee

e

e

eh

h

eh

Red

Oxeehh

eehh

eehh

eehh

eehh

ee

hh

ee ee eeee ee

eeee

ee

ee

eehh

hh

eehh

Red

OxTiO2

CdSe hν

CdSeTiO2

VB

CB

VB

CB

hν

hν

e

TiO2CdSe

CdSeTiO2

VB

CB

VB

CB

hν

CdSeTiO2

VB

CB

VB

CB

hν

hν

e

TiO2CdSehν

ee

TiO2CdSe

eh

eh

eh

eh

eh

e

h

e e ee e

ee

e

e

eh

h

eh

Red

OxTiO2

CdSe hν

eh

eh

eh

eh

eh

e

h

e e ee e

ee

e

e

eh

h

eh

Red

Oxeehh

eehh

eehh

eehh

eehh

ee

hh

ee ee eeee ee

eeee

ee

ee

eehh

hh

eehh

Red

OxTiO2

CdSe hν

CdSeTiO2

VB

CB

VB

CB

hν

hν

e

TiO2CdSe

CdSeTiO2

VB

CB

VB

CB

hν

CdSeTiO2

VB

CB

VB

CB

hν

hν

e

TiO2CdSehν

ee

TiO2CdSe

3. Quantum Dot Sensitized Solar Cell (QDSSC)

VB

CB

Ox

Redhν

et ht

VB

–

+

+

–CB

TiO2

CdSe

hν

e

OR

Photoelectrochemistry

pump probe

detector

Spectroscopy

GERISCHER H, LUBKE MA PARTICLE-SIZE EFFECT IN THE SENSITIZATION OF TIO2 ELECTRODES BY A CDS DEPOSITJOURNAL OF ELECTROANALYTICAL CHEMISTRY 204 (1-2): 225-227 1986

400 450 500 550 600 650

-0.04

0.5 1.0

3xΔOD

Time, ps

440 nm 530 nm

0

0.5

0

-0.08

e

d

a

c

b

1P(e)-1P3/2(h) 1S(e)-1S3/2(h)

Abso

rban

ce

ΔO

D

Wavelength, nm

a 0.2 psb 0.3 psc 0.4 psd 0.5 pse 1.1 ps

CdSe

VB

CBPhotoexcitation of CdSe Quantum Dots

Time, ps

0.5 1.0

3x

ΔO

D

440 nm

530 nm

pump probe

detector

450 500 550 600 650

-0.08

-0.04

0.00B

CdSe-MPA

ΔA

Wavelength, nm

1 ps 35 ps 400 ps 1500 ps

450 500 550 600 650

-0.08

-0.04

0.00C

CdSe-MPA-TiO2

ΔAWavelength, nm

1 ps 35 ps 400 ps 1500 ps

Charge Separation in TiO2/CdSe

Transient Bleaching Recovery of 3 nm CdSe Quantum DotsEx. 387 nm

Modulation of the charge injection process by controlling the particle size?

Eg=1.9 eV

e

CdSe TiO2

Eg=2.4 eV

CdSe TiO2

ee

h h

Slow Fast

Eg=1.9 eV

ee

CdSe TiO2

Eg=2.4 eV

CdSe TiO2

ee

h h

Slow Fast

CdSe2.4 nmCdSe

7.5 nmTiOTiO22

e e

400 500 600 700-0.06

-0.04

-0.02

0.00

ed

c

a

b

ΔA

Wavelength, nm

CdSea 7.5 nm (Eg 1.92 eV)b 4.6 nm (Eg 1.99 eV)c 3.5 nm (Eg 2.18 eV)d 2.7 nm (Eg 2.35 eV)e 2.4 nm (Eg 2.44 eV)

0.0

0.2

0.4

400 500 600 700

e dc b

a

Wavelength, nm

Abs

orba

nce

(A)

(B)

CdSe quantum dots of size 2.4 nm to 7,5 nm were excited with 387 nm laser pulse (130 fs)

As the particle size decreases from 7.5 nm to 2.4 nm, the first (1S3/2

1Se) excitonic peak shifts from 645 nm (1.92 eV) to 509 nm (2.44 eV).

Transient bleach corresponds to the first excitonic bleach

CdSe +hν → CdSe (ep +hp) → CdSe (es + hs)

Photoexcitation of CdSe Quantum Dots

Robel, Kuno, Kamat, JACS 2007; 129, 4136

0.0

0.8

0.0

0.8

0.0

0.8

0.0

0.8

0 500 1000 15000.0

0.8

b

b

a

a

a

a

a

size 2.7 nmλ(1S)=527 nm




b

b

b


Time (ps)

Nor

mal

ized

ble

ach

0.0

0.8

0.0

0.8

0.0

0.8

0.0

0.8

0 500 1000 15000.0

0.8

b

b

a

a

a

a

a





b

b

b


Time (ps)

Nor

mal

ized

ble

ach

ΔA(t)=ΔA(0)×exp[-(t/τ)β]

- where τ is the peak value of the characteristic lifetime

Analysis of Bleaching Recovery

CdSe (es) + TiO2 → CdSe + TiO2(e)

Electron transfer between CdSe and TiO2

Robel, Kuno, Kamat, JACS 2007; 129(14) pp 4136 - 4137

Diameter

[nm]

Eg

[eV]

τCdSe

[ps]

βCdSe τCdSe-TiO2

[ps]

βCdSe-TiO2 ket

[s-1]

7.5 1.92 2332 0.697 2281 0.755 9.58×106

4.6 1.99 7224 0.474 4961 0.446 6.3×107

3.5 2.18 4420 0.417 1117 0.475 6.7×108

2.7 2.35 6739 0.457 357 0.505 2.65×109

2.3 2.44 23119 0.51 83 0.493 1.2×1010

ΔA(t)=ΔA(0)×exp[-(t/τ)β]- where τ is the peak value of the characteristic lifetime

Size Dependent Quenching Phenomenon

1/τ’ – 1/τ = ket

0.4 0.6 0.8106

107

108

109

1010

k et, s

-1

-ΔG ,eV

7.5 nm

3.5 nm2.7 nm

4.6 nm

2.4 nm-0.9 -1.1 -1.3

ECB, V vs. NHE

0.4 0.6 0.8106

107

108

109

1010

k et, s

-1

-ΔG ,eV

7.5 nm

3.5 nm2.7 nm

4.6 nm

2.4 nm-0.9 -1.1 -1.3

ECB, V vs. NHE

Eg=1.92 eV

e

h TiO2

e

Eg=2.4 eV

h

CdSe2.4 nm

CdSe7.5 nm

ket= 107 s-1 ket= 1.2x1010 s-1

CdSe2.4 nm

CdSe7.5 nm

TiOTiO22

ee

Size Dependent Electron transfer between CdSe and TiO2

Robel, Kuno, Kamat, JACS 2007; 129 pp 4136 - 4137

Linking Q-CdSe to TiO2 particles

CdSeTiO2

Electrode

hν

e

OTE/TiO2/CdSeElectrode

Chemically Modified TiO2 film

CdSe

TiO2OTE

HOOCSH

HOOCSH

HOOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCS-

OOCS-

OOCS-

Bifunctional linker molecule

OTE/TiO2/CdSeElectrode

Chemically Modified TiO2 film

CdSe

TiO2OTE

HOOCSH

HOOCSH

HOOCSH

HOOCSH

HOOCSH

HOOCSH

HOOCSH

HOOCSH

HOOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCSH

OOCS-

OOCS-

OOCS-

OOCS-

OOCS-

OOCS-

OOCS-

OOCS-

OOCS-

Bifunctional linker molecule

a b c d e

-0.75

-0.75

0nm

0 2 μm

2 μm

0

150 nm

J. Am. Chem. Soc. 2006,128, 2385-2393

0.2 0.0 -0.2 -0.4 -0.6 -0.8 -1.0

200

100

0

TiO2/CdSe

TiO2

Phot

ocur

rent

, μA

Voltage vs. SCE, V

a

b

0.2 0.0 -0.2 -0.4 -0.6 -0.8 -1.0

200

100

0

TiO2/CdSe

TiO2

Phot

ocur

rent

, μA

Voltage vs. SCE, V

a

b

Photoelectrochemical behavior of Q-CdSe-TiO2 films

I-V characteristics of (a) OTE/TiO2 and (b) OTE/TiO2/MPA/CdSe films. Electrolyte 0.1 M Na2S. The filtered lights allowed excitation of TiO2 and CdSe films at wavelengths greater than 300 and 400 nm respectively

TiO2 hν

e

O

R

PotentiostatWE CE

RE

300 400 500 600 700

0.0

0.2

0.4

0.6 3.7 nm 3.0 nm 2.6 nm 2.3 nm

Abs

orba

nce

Wavelength, nm

Modification of TiO2 Films with Different Size CdSe Particles

2.3nm2.6nm

3.0nm3.7nm

450 500 550 600 650 7000.0

0.3

0.6

0.9

3.7 nm 3.0 nm 2.6 nm 2.3 nm

Abs

orba

nce

Wavelength, nm

2.3nm2.6nm

3.0nm3.7nm

350 400 450 500 550 600 650 700

0

10

20

30

40

50 (A) 3.7 nm 3.0 nm 2.6 nm 2.3 nm

Wavelength (nm)

IPC

E (%

)

Tuning the Photoresponse of Quantum Dot Solar Cells

hν

e

O

R

CdSeTiO2

VB

CB

ee

e

hh h

O

e

h

R

E

J. Am. Chem. Soc., 130 (12), 4007 -4015, 2008

IPCE or Ext. Quantum Eff.

= (1240/λ) x (Isc/Iinc) x 100

hν

e

O

R

0 50 100 150

0

1

2

3(A) 3.7 nm

3.0 nm 2.6 nm 2.3 nm

Time, sec

Cur

rent

den

sity

, mA

/cm

2

Sol

ar F

lux

Photocurrent Response

Efficiency of Charge Injection vs. Light absorption

Can we employ the nanowire/nanorodarchitecture to improve the performance of

quantum dot solar cells?

Ti/TiO2 nanotubes

(b)

CdSee e e

OTE/TiO2 nanoparticles

(a)

CdSe

e

TiO2

Recent advances

Nanowire dye-sensitized solar cellsLAW, GREENE, JOHNSON, SAYKALLY,YANG Nature Materials 4 , 455, 2005

Fast Electron Transport in Metal Organic Vapor Deposition Grown Dye-sensitized ZnO Nanorod Solar CellsGaloppini, Rochford, Chen, Saraf, Lu, Hagfeldt, and Boschloo J. Phys. Chem. B; 2006; 110 16159

Electron transport in solar cells with ZnO-nanorod electrodes was about 2 orders of magnitude faster (30μs) than ZnO-colloid electrodes

Leschkies, K. S et al Photosensitization of ZnO nanowires with CdSe quantum dots for photovoltaic devices.

Nano Lett., 2007. 7, 1793-1798.

Mor, G. K. et al Use of highly-ordered TiO2 nanotube arrays in dye-sensitized solar cells.

Nano Lett., 2006. 6, 215-218.

Martinson, A. B. F. et al., ZnO nanotubebased dye-sensitized solar cells ZnOnanotube based dye-sensitized solar cells.

Nano Lett., 2007. 7, 2183-2187.

5μm

2μm 500nm

200nm

A B

C D

2.3nm2.6nm

3.0nm3.7nm

(B)

2.3nm2.6nm

3.0nm3.7nm

(A)

2.3nm2.6nm

3.0nm3.7nm

(C)

Photoemission ofCdSe/glass and CdSe/TNP

Emission spectra of CdSe QDs (a, c) on glass and (b, d) chemically bound to TiO2 nanoparticle films at 2 different sizes of QDs (2.7 and 3.7 nm). Excitation was at 480 nm.

×3×3

500 550 600 650 7000.0

0.4

0.8

1.2

3.7 nm diameterc. CdSe/glassd. CdSe/TiO

2

db

ca

Inte

nsity

(a.u

.)

Wavelength, nm

2.6 nm diametera. CdSe/glassb. CdSe/TiO

2 0 5 10 15 20 25

1

10

100

1000

10000

prompt

CdSe/TiO2(NP)

CdSe/TiO2(NT)

CdSe/glass

(B) 3.7 nm CdSe

Time, ns

Inte

nsity

(a.u

.)

<t>, ns

ket, sec-1

4.1

7.9

0.4 2.5E+09

1.3 6.3E+08

0.4 2.2E+09

1.5 5.5E+08

CdSe/glass

2.6nm

3.7nm

CdSe/tnp

2.6nm

3.7nm

CdSe/tnt

2.6nm

3.7nm

ISC

mA/cm2

VOC

VPmax

mW/cm2

FF

CdSe-TNP 1.64 0.591 0.25 0.26

CdSe-TNT 1.95 0.582 0.29 0.26

Quantum Dot Solar Cells – Particle versus Tube Architecture

200nm

500nm

350 400 450 500 550 600 650 700

0

10

20

30

40

50

dc

b

a

(A) TiO2(NP) CdSe Diametera. 3.7 nmb. 3.0 nmc. 2.6 nmd. 2.3 nm

Wavelength (nm)

IPC

E (%

)

350 400 450 500 550 600 650 700

0

10

20

30

40

50

b

cd

a

(B) TiO2 (NT) CdSe Diametera. 3.7 nmb. 3.0 nmc. 2.6 nmd. 2.3 nm

Wavelength (nm)

IPC

E (%

)

J. Am. Chem. Soc., 130 (12), 4007 -4015, 2008 Power conversion efficiency ~1%

Scale bars: Top 500nm, bottom 50nm

Unsonicated TiO2 NT 0 dip 5 dip 10 dip 20 dip

100kX

500kX

Depositing CdS quantum dots on TiO2 nanotubes

(TiO2) (TiO2)CdS(TiO2)Cd2+ Wash WashCd2+ S2-

1 dip cycle

IPCE: CdS on Single TiO2 electrode

0

10

20

30

40

50

60

350 400 450 500 550 600

Wavelngth (nm)

IPCE

(%) Tubes

5 dip10 dip20 dip

Reflectence Absorbtion Spectra: CdS/P25/OTE

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

350 400 450 500 550 600

Wavelength (nm)

Abs

orba

nce

TiO2

5dip

10dip

15dip

20dip

Photocurrent Response of TiO2(nanotube)CdS Films

hνOR

AdvantagesHigh surface area

Good electronic conductivity, excellent chemical and electrochemical stabilityGood mechanical strength

Carbon nanostructures as conduits to transport Carbon nanostructures as conduits to transport charge carrierscharge carriers

c

GoalEffective utilization of carbon nanostructures for improving theperformance of energy conversion devices- To develop electrode assembly with CNT supports- Improve the performance of light harvesting assemblies- Facilitate charge collection and transport in nanostructured

assemblies

Pt

…..towards achieving ordered assemblies on electrode surface

SWCNT- TiO2 composite films

• Mesoscopic TiO2 films are extensively used in Dye-Sensitized Solar Cells

• A carbon nanotube support architecture can disperse the TiO2 particles and facilitate charge collection and charge transport within the film.

• The first step is to design the SWCNT-TiO2 network and test the feasibility of the composite system in solar cells

et

ht

VB

–

+

+

–CB

et

ht

VB

–

+

+

–CB

hνhν

eee

Kongkanand, A.; Domínguez, R.M.; Kamat, P.V., Single Wall Carbon Nanotube Scaffolds for Photoelectrochemical Solar Cells. Capture and Transport of Photogenerated Electrons.Nano Lett., 2007. 7, 676-680.

Vietmeyer, F.; Seger, B.; Kamat, P.V., Anchoring ZnO Particles on Functionalized Single Wall Carbon Nanotubes. Excited State Interactions and Charge Collection. Adv. Mater., 2007, 19: 2935-2940

400 600 800 10000.0

0.2

0.4

0.6

0.8

c

a

bAbs

Wavelength, nm

SWCNT+TOABin THF

Sonicationfor 1 min

After Electro-deposition

on OTE

OTE/SWCNTSWCNT/TOABin THF

OTE/SnO2

OTE/SnO2/SWCNT

OTE/SWCNT

Electrophoretic Deposition of SWCNT on Electrode Surfaces

200 nm

B

200 nm

B

200 nm

J. Am. Chem. Soc., 2004. 126 10757-10762.

SWCNT-TiO2on CFE

5 μm

5 μm

1 μm

1 μm

50 μm50 μm50 μm

50 μm50 μm50 μm

50 μm

50 μm50 μm50 μm

B

CFE/TiO2

B

CFE/TiO2

A

CFE

A

CFE

C

CFE/SWCNT

C

CFE/SWCNT

D

CFE/SWCNT/TiO2

D

CFE/SWCNT/TiO2

SWCNT –DepositionOn CFE

TiO2 DepositionOn CFE

Carbon Fiber Paper(CFE)

0 20 40 60

0

20

40

60

b

a

a) SWCNT/TiO2 b) TiO

2

Time, sec

Phot

ocur

rent

, μA

/cm

2

Photocurrent GenerationCFE/TiO2 versus CFE/SWCNT –TiO2

UV light

Nano Lett., 2007. 7, 676-680

350 400 450 500

0

5

10

15

d

c

b

a

a) SWCNT/TiO2 at 0V b) SWCNT/TiO2 at SC c) TiO2 at 0V d) TiO2 at SC

Wavelength, nm

IPC

E, %

Higher IPCE (increase of factor ~2) was observed for mesoscopicCFE/SWCNT-TiO2 films

The results are indicative of better charge collection and transport provided by the SWCNT -Network

0 1 2 3 40

10

20

30

40

50

60

b

a

a) SWCNT/TiO2 b) TiO2

TiO2 loadings (mg/cm2)

Pho

tocu

rren

t (μA

/cm

2 )

1 μm

Dependence of TiO2/SWCNT Ratio on the Photocurrent Generation

Increasing the TiO2 concentration results in enhanced photocurrent as they are dispersed on SWCNT network.

At concentrations greater than 2 mg/cm2 the beneficial effect of SWCNT disappears. Under these conditions. TiO2 particles aggregate and the charge recombination dominates

Nano Lett., 2007. 7, 676-680

Where do we go from here?

350 400 450 500 550 600 650 7000

1

2

3

4

5

c

b

IPC

E (%

)

Wavelength (nm)

(a) nC60

(b) CdSe(c) CdSe/nC60

a

0 1 μm

1 μm

00

1.2 μm

Capping CdSe with an Electron Acceptor Shell

Electrophoreticdeposition of Cluster films

C60 CdSeC60

CdSe

J. Am. Chem. Soc., 2008, 130, 8890–8891

Organized light harvesting assembly using carbon nanostructureshνhν

eeh

eeh

eeh

eeh

eeh

eeh

0.6 μm

TiO2‐GO

TiO2-GR

hνhν

h

e

TiO2

hν

Gra

phen

eO

xide

Red

uced

G

raph

ene

Graphene-Semiconductor Nanocomposites ACS Nano, 2008, 2, 1487-1491

15 nm

0

0 1 μm

1 μm

0

• Unique properties of quantum dots offer new opportunities to develop low-cost and high efficiency solar cells

• 1-D architectures are useful for designing next generation solar cells.

• Opportunities exist for carbon nanostructures to facilitate capture and transport of electrons in nanostructure semiconductor based solar cells.

Summary

Kamat, P. V. Meeting the Clean Energy Demand: Nanostructure Architectures for Solar Energy Conversion (Review)J. Phys. Chem. C, 2007. 111 2834 - 2860.

Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters (CentennialFeature) J. Phys. Chem. C 2008, 112, in press

Researchers/CollaboratorsGraduate students Post-Docs/Visiting ScientistsBrian Seger (Chem. Eng.) Jin Ho BangDavid Baker (Chem. Eng.) Kevin Tvrdy (Chemistry) Undergraduate studentsClifton Harris (Chemistry) Pat BrownMatt Baker (Physics) Chris RodriguezIan Lightcap (Chemistry) David RiehmPhilix Vietmeyer (Chemistry) Rachel StaranYanghai Yu (Chem. Eng.)Istvan Robel (Physics)

CollaboratorsDr. K. G. Thomas (India)Prof. Fukuzumi (Osaka U.)Prof Ken Kuno (UND)Prof. K. Vinodgopal (IUN)

What will the future hold?

Over the last twenty years, the per-kWh price of photovoltaics has dropped from about $500 to nearly $5; think of what the next twenty years will bring.

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1938-2 workshop on nanoscience for solar energy conversion · workshop on nanoscience for solar...

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