[PPT] - Recent Advances in Dye-Sensitized Solar Cells Yong Soo Kang g g PowerPoint Presentation

SLIDE 1

Recent Advances in Dye-Sensitized Solar Cells

Yong Soo Kang

Center for Next Generation Dye sensitized Solar Cells

g g

Center for Next Generation Dye-sensitized Solar Cells and Department of Energy Engineering p gy g g Hanyang University, Seoul

SLIDE 2

What Will Happen in the Future?

Energy Future

Latin Africa 6% Middle East 6% ETC 1%

OECD 40%

Transition Economies Latin America 5% 6% 6%

8.3 billion Asia 34%

8%

2007 2030 2030 50 % 2000 6.7 billion

Transition economics

2000 2008 4.5 billion 2005

Total Primary Energy Supply

1990

Ozone Hole over the Antarctica

1980

World Population

Energy Demands Environmental Problems World Population

SLIDE 3

Change in Oil Price

160 120 140

$145 6/2008

$77.67

80 100

Barrel

$ 3/2010

40 60

$44.17 $/B

20

$44.17

`96 `98 `00 `02 `04 `06 `08

SLIDE 4

SLIDE 5

2100년 에너지 시나리오 Future Market

Market share for solar cells will be almost 70 % of the total energy demands in 2100 (www.solarwirtsch.de).

SLIDE 6

Electricity Production Cost

25

$1/W

Ref: coal-fired power $0.99/W

15 20

$1/W

in 2010

$4/W

in 10 15

$/W

in 2007 5

$

1980 1990 2000 2010 2020

Average cost per watt of PV module 1985-2010. (S E th P li I tit t 2007)

1980 1990 2000 2010 2020

(Source: Earth Policy Institute, 2007)

Center for Next Generation Dye-sensitized Solar Cells

6

SLIDE 7

Electricity Production Cost

Center for Next Generation Dye-sensitized Solar Cells

7

SLIDE 8

Market of Solar Cells

28%

(5.4 GW)

New Emerging Bulk-Si iga Watt

72%

G

72%

(18.1 GW)

World Market (2011): $121.0 billion S i d t M k t (2008): $260 0 billi Year Semiconductor Market (2008): $260.0 billion

[Solar Annual 2007 (http://www.photon-consulting.com)] [World Semiconductor Trade Statistics (http://www.wsts.org)]

SLIDE 9

Why DSSCs?

transparent flexible durable p colorful efficient Low cost

SLIDE 10

Environmentally Benign

SLIDE 11

Configuration of DSSC

electrolyte (liquid, gel and solid )

e-

I3

I3
I-

I- I-

e-

Pt Pt

TCO TCO TCO TCO

charge transfer layer dye g y

11

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 12

Nanoporous Nanoporous Semiconductor Semiconductor Nanoporous Nanoporous Semiconductor Semiconductor (charge transfer layer): (charge transfer layer): (charge transfer layer): (charge transfer layer): TiO TiO2 Layer Layer

2

SLIDE 13

Issues in semiconductor layer

Basic Requirements:

1. Proper energy level of conduction band
2. Wide band gap
3. High electron conductivity
4. Slow recombination

Current Issues Connectivity among nanoparticles Concentration of surface states Adhesion to transparent conducting oxide d es o to t a spa e t co duct g o de Low temperature processing

50 nm

SLIDE 14

Novel Submicro-Structured TiO2 Layer

Hydrothermal process : TiCl Hydrothermal process : TiCl4 with water, urea and ethanol

submicro-structured
submicro-structured

submicro structured spherical TiO2 particles comprising primary nanoparticles submicro structured spherical TiO2 particles comprising primary nanoparticles nanoparticles

large surface area

(116.49m2/g) (ref: 77 m2/g) nanoparticles

large surface area

(116.49m2/g) (ref: 77 m2/g)

Y K Sun et al Electrochem Commun (accepted)

Center for Next Generation Dye-sensitized Solar Cells

Y. K. Sun et al. Electrochem. Commun. (accepted)

SLIDE 15

Performance of DSSCs

100 synthesized TiO2 (4.7μm) 18

2)

<J-V curves> <IPCE curves>

60 80 synthesized TiO2 (4.7μm) synthesized TiO2 (8.7μm) p25 (4.7μm) p25 (8.7μm)

)

12 14 16

ty (mA/cm

2

40 60

IPCE (%)

6 8 10

synthesized TiO (4 7μm) rent densit

20 2 4

synthesized TiO2 (4.7μm) synthesized TiO2 (8.7μm) P25 (5.1 μm) P25 (8.4 μm) Photocurr

400 500 600 700 800

Wavelength (nm)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 μ

Voltage (V)

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 16

Performance of DSSCs

Sample P25 Novel TiO2 Thickness (μm)

5.1 8.4 4.7 8.7

Adsorbed Dye ( × 10-7 mol/cm2)

0.485 0.692 1.05 1.48

Open Circuit Voltage (VOC, mV)

763 763 734 729

Short Circuit Current Density (JSC mA/cm2)

7.98 10.21 13.15 14.44

(JSC, mA/cm ) Fill Factor (FF)

72.3 73.1 72.4 71.7

Efficiency (η, %)

4.40 5.69 6.99 7.54

Y K Sun et al Electrochem Commun (accepted)

Center for Next Generation Dye-sensitized Solar Cells

Y. K. Sun et al. Electrochem. Commun. (accepted)

SLIDE 17

Sensitizer : Dye Sensitizer : Dye Sensitizer : Dye Sensitizer : Dye

SLIDE 18

Issues in dyes

Basic Requirements:

1. Panchromatic utilizing

whole range of visible light (400 ~ 900 nm)

2. High IPCE (incident photon-to-current conversion efficiency).
3. Strong chemical bonding on semiconductor oxide surface

g g

4. Long-term chemical stability
5. Low cost

Organic Dyes Organic Dyes

somewhat low efficiency:

(7~8 % at 100 mW/cm2) Organometallic Dyes Organometallic Dyes

high efficiency:

(~10 5 % at 100 mW/cm2) (7 8 % at 100 mW/cm )

low chemical stability
low cost

( 10.5 % at 100 mW/cm )

light absorption

mostly from 400-600 nm

rather high cost

rather high cost

SLIDE 19

Benzo[cd]indole dyes

2.4 2.6 2.8

425nm

1 4 1.6 1.8 2.0 2.2

JK-51 JK-52

rbance

JK-51

N S S COOH NC

0 4 0.6 0.8 1.0 1.2 1.4

445nm Abso

JK-51

400 500 600 0.0 0.2 0.4

Wavelength(nm)

JK 52

N S S COOH CN

Dye λabs/nm (ε/M-1cm-1) Eox/V E0-0/V ELUMO/V

JK-52

JK-51 445 (15188) 1.30 (0.27) 2.38

1.08

JK-52 425 (48140) 1.53 (0.39) 2.44

0.91
J. Ko et. al. J. Photochem. Photobiol. A Chem. 2009, 201, 102-110

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 20

Benzo[cd]indole dyes J-V curves IPCE

70 80 70 80 70 80

JK-51 JK-52 N719

14 15 16 17 18 14 15 16 17 18

JK-52 JK-51 m-2

30 40 50 60 30 40 50 60 30 40 50 60

IPCE (%)

7 8 9 10 11 12 13 7 8 9 10 11 12 13

nt Density / mAc

400 500 600 700 800 10 20 30 400 500 600 700 800 10 20 30 400 500 600 700 800 10 20 30 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 1 2 3 4 5 6 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 1 2 3 4 5 6

Photocurre

400 500 600 700 800 400 500 600 700 800 400 500 600 700 800

Wavelength (nm)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Voltage / V

Dye Jsc (mAcm-2) Voc (V) FF η (%) JK-51 17.43 0.680 0.71 8.42 JK-52 15.56 0.626 0.70 6.88

J. Ko et. al. J. Photochem. Photobiol. A Chem. 2009, 201, 102-110

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 21

Indolo[1.2-f]phenanthridine dyes

N S CN S COOH

JK-60 JK 60

N S S COOH NC Dye λabs/nm (ε/M-1cm-1) Eox/V E0-

0/V

ELUMO/V JK 60 (soild) 339 (39 400) 453 (22 600) 1 01 2 33 1 32 NC

JK-61

JK-60 (soild) 339 (39 400), 453 (22 600) 1.01 2.33

1.32

JK-61 (dash) 411 (37 600) 1.09 2.19

1.12
J. Ko et. al. Tetrahedron 2009, 65, 5302-5307

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 22

Indolo[1.2-f]phenanthridine dyes J-V curves IPCE

Dye λabs

a, nm

(ε/dm3mol-1cm-1) Eox

b, V

E0-0

c, V

ELUMO

d,

V Jsc, mAcm-2 Voc, V FF η (%) JK-60 339 (39 400) 453 (22 600) 1.01 2.33

1.32

12.17 0.69 0.73 6.22 JK-61 411 (37 600) 1.09 2.19

1.12

15.81 0.73 0.72 8.34

J. Ko et. al. Tetrahedron 2009, 65, 5302-5307

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 23

Encapsulated dye by Cyclodextrin

J. Ko et. al. Angew. Chem. Int. Ed. 2009, 48, 5938-5941

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 24

Encapsulated dye by cyclodextrin

100 16

IPCE J-V curves

60 70 80 90 ) 10 12 14 ty (mA/cm2)

JK-2 JK-2+DCA

20 30 40 50 IPCE (%

JK-2 JK-2+DCA aCD/JK-2 bCD/JK-2 rCD/JK-2

4 6 8

Current densit bCD+JK-2 aCD+JK-2 rCD+JK-2 400 500 600 700 800 10 Wavelength (nm)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 2

Voltage (V)

Dye Jsc (mAcm-2) Voc (V) FF η (%) JK-2 14.51 0.70 0.73 7.42 JK-2+DCA 14.85 0.73 0.74 8.01 α-CD/JK-2 14.26 0.71 0.73 7.41 β-CD/JK-2 15.34 0.76 0.74 8.65 γ-CD/JK-2 13.68 0.74 0.73 7.42

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 25

Durability of β-CD/JK-2

14 16

J /mA cm

2

200 400 600 800 1000 8 10 12 14

Jsc/mA cm

750 800

V / V

Ionic liquid electrolye (red line): 0.2 M iodine, 0.5 M NMBI, 0.1 M GuNCS in PMII/EMINCS

0.75 0.80

FF

200 400 600 800 1000 600 650 700

Voc/mV

(13/7). Quasi-soild-state electrolyte (blue line): 0.1 M iodine, 0.5M NMBI, 0.6 M DMPII, 5 wt% PVDF-HFP in MPN.

200 400 600 800 1000 0.60 0.65 0.70

FF

7 8

After 1000 h of light soaking Quasi-soild-state electrolyte

200 400 600 800 1000 4 5 6 7

t / hr E/ %

E l ti f l ll t ith β

Quasi soild state electrolyte The initial efficiency of 7.40% is slightly decreased to 6.31% Ionic liquid electrolye

Evolution of solar cell parameters with β- CD/JK-2 during visible-light soaking (AM 1.5G, 100 mW/cm2) at 60 ℃. A 420 nm cut-

ff filter was put on the cell surface during

ill i ti

q y The initial efficiency of 5.93% is slightly increased to 6.48%.

illumi-nation.

Center for Next Generation Dye-sensitized Solar Cells

J. Ko et. al. Angew. Chem. Int. Ed. 2009, 48, 5938-5941

SLIDE 26

Organic Dyes: Organic Dyes: Efficiency Efficiency improvement improvement

100 IPCE 50 IPCE 50 11 % 15 % 300 900 600 wavelength (nm) 300 900 600

SLIDE 27

Electrolyte Interfaces: Electrolyte Interfaces: blocking blocking l t bi ti l t bi ti electron recombination electron recombination By By coadsorbent coadsorbent By By coadsorbent coadsorbent

SLIDE 28

Passivation of TiO2 Surfaces with Oligomeric Co-Adsorbents

Passivation of TiO2 Surfaces

Passivation of TiO2 Surfaces with Oligomeric Co-Adsorbents

I3

I3
I3
I3
e-

e- e- TiO2 TiO2 TiO2

TCO

e e- e- e- I3

e-

Blocking Electron

I3

I3
Recombination

Dye Co-Adsorbent

SLIDE 29

Chemical Structure of Oligomeric Co-Adsorbents

Oligomeric Co Oligomeric Co-

adsorbents

adsorbents

COOTBA O

PEG Co-Adsorbent

O N N C Ru N N C S N O O n OH N C COOTBA N C S O O

Adsorption on vacant TiO2 sites

PS Co-Adsorbent

N719 dye dso pt o o vaca t O2 s tes

Blocking electron recombination with I3

at TiO2 electrode / (polymer) electrolyte interfaces

P

ti f d ti

Prevention of dye aggregation Band-edge shift Enhancement of TiO2 pore filling Chain length effect

SLIDE 30

Adsorption Mode of Co-Adsorbents on TiO2 S urface

Polymer Adsorption Modes on Flat Surface

Polymer Adsorption on Flat Surface

Chain Conformation of a Single Chain Adsorbed
n a Flat Surface

Low Mol Wt Co-Adsorbents

n TiO2 surface

Organic Molecules

2

Filling vacant TiO2 sites & blocking

recombination with I3

in electrolyte

Loop Tail Brush Thickness PEG Co-Adsorbents

Increase in Grafting Density

Train Miscible with

both ACN & PEO Electrolytes Poor Solvent Quality Density

Non-Interacting System Interacting System Chain Collapse in Poor Solvent PS Co-Adsorbents

Increase in Grafting Density Co-Adsorbent Dye

Immiscible with Both

ACN & PEO Electrolytes y

Increase in Chain Length

SLIDE 31

Effect of Mixing Protocol of Dye & Co-Adsorbent (I)

Performance of DSSCs with Coadsorbent

10 12

Measured @ 100 mW/cm

2

cm

2)

6 8

Ref A 0.3 mM

ent (mA c

2 4

A 0.3 mM A 1 mM A 5 mM A 10 mM A 20 mM A 30 mM

hotocurre

Protocol A (Sequential Adsorption)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

A 30 mM A 40 mM

Ph Potential (V)

A (Sequential) Voc (V) Jsc (mA/cm2) FF Efficiency (% ) Ref 0.71 9.4 0.68 4.6 0.3 mM 0.71 9.7 0.66 4.6 1 mM 0.71 10.2 0.66 4.8 5 mM 0.73 10.4 0.68 5.2 10 M 0 74 10 7 0 68 5 4

Dye : 0.3 mM N719 in ACN/tert-BuOH (1:1 v/v)
Co-adsorbent : 0 ~ 40 mM in ACN/tert-BuOH (1:1 v/v)

El t l t 0 5 M MPII 0 05 M I i MPN

10 mM 0.74 10.7 0.68 5.4 20 mM 0.76 10.8 0.69 5.6 30 mM 0.76 11.0 0.68 5.7 40 mM 0.77 10.1 0.71 5.6

Electrolyte : 0.5 M MPII + 0.05 M I2 in MPN
TiO2 film thickness : 12 µm, Active area : 0.25 cm2
Measured under AM 1.5, 100 mWcm-2

with shading mask

40 mM 0.77 10.1 0.71 5.6

Center for Next Generation Dye-sensitized Solar Cells

SLIDE 32

Effect of Passivation of TiO2 Surface (II)

Suppressed Electron Recombination

Electrochemical Impedance S

pectroscopy (EIS )

0 0

Liquid DSSCs Solid DSSCs

20.0

0.0

20.0

0.0

40.0

20.0

Z" ( Ω )

40.0

Z" ( Ω )

60.0

Prisine TiO2 PEG co-adsorbent

Z

60.0

Pristine TiO2 PEG co-adsorbent

Z

0.0 50.0 100.0 150.0 200.0

PEG co adsorbent

Z' ( Ω )

0.0 50.0 100.0 150.0 200.0 250.0

80.0

Z' ( Ω )

under Dark Condition

S

d El t R bi ti t TiO El t d / El t l t I t f

Suppressed Electron Recombination at TiO2 Electrode / Electrolyte Interfaces Center for Next Generation Dye-sensitized Solar Cells

SLIDE 33

Effect of Passivation of TiO2 Surface (V)

Upward Shift of Band Edge

Measurement of Band-Edge S

hift of TiO2 Electrodes Photoelectron Spectrometer (AC-2)

Concentration of co-adsorbent Work function (eV)

150 200

^0.5]

Ref A 1 mM A 10 mM A 30 mM

vacuum

5.25 eV

Reference 5.32 eV A 1 mM 5.29 eV A 10 mM 5 26 eV

50 100

n Yield [cps

A 30 mM 5.32 eV

EF CB EF

A 10 mM 5.26 eV A 30 mM 5.25 eV

4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2

Emissio

3.2 eV

VB

Energy (eV)

Band-edge shift less negatively Center for Next Generation Dye-sensitized Solar Cells

SLIDE 34

Summary

1. Novel Submicro-Structured TiO2 Layer

with High Surface Area with High Surface Area. 2 New Highly Efficient and Durable Organic Dyes

2. New Highly Efficient and Durable Organic Dyes.

3 Coadsorbents to Block Electron Recombination

3. Coadsorbents to Block Electron Recombination

and to Shift the Band Edge Upward.

SLIDE 35

Acknowledgements

Fund through the ERC Program from Ministry of Education, Science and Technology of Korea Ministry of Education, Science and Technology of Korea Center for Next Generation Dye-Sensitized Solar Cells (2008 ~ 2015, 14 Professors) Prof Jae Jung Ko (Korea U )

Prof. Jae Jung Ko (Korea U.)
Prof. Yang Kook Sun (Hanyang U.)
Prof. Kookheon Char (Seoul National U.)
Prof. Kookheon Char (Seoul National U.)

Students: Seoul National U. (Yong Gun Lee) Hanyang U. (June Hyuck Jung, Suil Park, Donghoon Song Tae Wook Son) Donghoon Song, Tae Wook Son)

SLIDE 36

Thank you very much

SLIDE 37

Effect of Mixing Protocol of Dye & Co-Adsorbent (II)

Performance of DSSCs

12

Protocol A (Sequential Adsorption)

0.76 0.77

Voc Jsc Pho

0.74 0.75

ltage (V)

11

tocurren

0.72 0.73

Photovo

10

nt (mA/cm

10 20 30 40 0.71 9

m

2)

10 20 30 40

Concentration of PEG co-adsorbent (mM)

J-V Data of DSSCs as a Function of Concentration of PEG-Based Co-Adsorbent

Center for Next Generation Dye-sensitized Solar Cells