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

Recent Advances in Dye-Sensitized Solar Cells Yong Soo Kang g g Center for Next Generation Dye sensitized Solar Cells Center for Next Generation Dye-sensitized Solar Cells and Department of Energy Engineering p gy g g Hanyang University, Seoul

What Will Happen in the Future? Energy Future Middle ETC Africa East 1% Latin Latin 6% 6% 6% 6% America 8.3 billion 5% OECD Transition Economies 40% 8% Asia 2007 2030 34% 2030 6.7 billion 50 % 2000 2000 2008 Transition economics 4.5 billion 1990 1980 2005 Total Primary Energy Supply World Population Ozone Hole over the Antarctica Energy Demands World Population Environmental Problems

Change in Oil Price 160 140 $145 6/2008 120 $77.67 $ 3/2010 100 Barrel 80 $/B 60 40 $44.17 $44.17 20 0 `96 `98 `00 `02 `04 `06 `08

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

Electricity Production Cost 25 $1/W $1/W 20 in Ref: coal-fired power $0.99/W 2010 15 15 $4/W $/W 10 0 in in $ 2007 5 0 1980 1980 1990 1990 2000 2010 2020 2000 2010 2020 Average cost per watt of PV module 1985-2010. (S (Source: Earth Policy Institute, 2007) E th P li I tit t 2007) 6 Center for Next Generation Dye-sensitized Solar Cells

Electricity Production Cost 7 Center for Next Generation Dye-sensitized Solar Cells

Market of Solar Cells 28% New Emerging Bulk-Si (5.4 GW) iga Watt 72% 72% G (18.1 GW) Year World Market (2011): $ 121.0 billion Semiconductor Market (2008): $260.0 billion S i d t M k t (2008): $260 0 billi [Solar Annual 2007 (http://www.photon-consulting.com)] [World Semiconductor Trade Statistics (http://www.wsts.org)]

Why DSSCs? transparent p durable flexible colorful Low cost efficient

Environmentally Benign

Configuration of DSSC electrolyte (liquid, gel and solid ) e - - - I 3 I 3 Pt Pt TCO TCO I - I - I - TCO TCO e - dye charge transfer layer g y 11 Center for Next Generation Dye-sensitized Solar Cells

Nanoporous Nanoporous Semiconductor Nanoporous Nanoporous Semiconductor Semiconductor Semiconductor (charge transfer layer): (charge transfer layer): (charge transfer layer): (charge transfer layer): TiO TiO 2 Layer Layer 2

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

Novel Submicro-Structured TiO 2 Layer Hydrothermal process : TiCl 4 Hydrothermal process : TiCl with water, urea and ethanol • submicro-structured • submicro-structured submicro structured submicro structured spherical TiO 2 particles spherical TiO 2 particles c omprising primary c omprising primary nanoparticles nanoparticles nanoparticles nanoparticles • large surface area • large surface area (116.49m 2 /g) (ref: 77 m 2 /g) (116.49m 2 /g) (ref: 77 m 2 /g) Y K Sun et al Electrochem Commun (accepted) Y. K. Sun et al. Electrochem. Commun . (accepted) Center for Next Generation Dye-sensitized Solar Cells

Performance of DSSCs <J-V curves> <IPCE curves> 100 18 synthesized TiO 2 ( 4.7 μ m ) synthesized TiO 2 ( 4.7 μ m ) 2 ) 2 ty ( mA/cm 16 synthesized TiO 2 ( 8.7 μ m ) 80 14 p25 ( 4.7 μ m ) p25 ( 8.7 μ m ) 12 60 60 IPCE (%) ) rent densit 10 8 40 6 synthesized TiO 2 ( 4.7 μ m ) synthesized TiO ( 4 7 μ m ) Photocurr synthesized TiO 2 ( 8.7 μ m ) 20 4 P25 ( 5.1 μ m ) 2 P25 ( 8.4 μ m ) μ 0 0 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 400 500 600 700 800 Wavelength (nm) Voltage (V) Center for Next Generation Dye-sensitized Solar Cells

Performance of DSSCs Sample P25 Novel TiO 2 Thickness ( μ m) 5.1 8.4 4.7 8.7 Adsorbed Dye 0.485 0.692 1.05 1.48 ( × 10 -7 mol/cm 2 ) Open Circuit Voltage 763 763 734 729 (V OC , mV) Short Circuit Current Density 7.98 10.21 13.15 14.44 (J SC mA/cm 2 ) (J SC , 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) Y. K. Sun et al. Electrochem. Commun . (accepted) Center for Next Generation Dye-sensitized Solar Cells

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

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 Organometallic Dyes Organometallic Dyes Organic Dyes Organic Dyes • high efficiency: • somewhat low efficiency: (~10 5 % at 100 mW/cm 2 ) (7~8 % at 100 mW/cm 2 ) ( 10.5 % at 100 mW/cm ) (7 8 % at 100 mW/cm ) • light absorption • low chemical stability mostly from 400-600 nm • low cost • rather high cost rather high cost

Benzo[cd]indole dyes 2.8 425nm 2.6 2.4 2.2 2.0 JK-51 JK-52 orbance 1.8 1.6 1.4 1 4 Abso S COOH 1.2 N S 1.0 NC 445nm 0.8 0.6 JK-51 JK-51 0 4 0.4 0.2 0.0 400 500 600 Wavelength(nm) N CN S S Dye λ abs /nm (ε/M -1 cm -1 ) E ox /V E 0-0 /V E LUMO /V COOH JK-52 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

Benzo[cd]indole dyes J-V curves IPCE JK-51 18 18 JK-52 80 80 80 17 17 N719 16 16 JK-52 15 15 70 70 70 m-2 JK-51 14 14 nt Density / mAc 13 13 60 60 60 12 12 11 11 IPCE (%) 50 50 50 10 10 9 9 40 40 40 8 8 7 7 30 30 30 30 30 30 Photocurre 6 6 5 5 20 20 20 4 4 3 3 10 10 10 2 2 1 1 0 0 0 0 0 400 400 500 500 600 600 700 700 800 800 0.0 0.0 0 0 0 0 0 1 0.1 0.1 0 1 0.2 0.2 0 2 0 2 0 3 0.3 0.3 0 3 0.4 0 4 0.4 0 4 0.5 0.5 0 5 0 5 0 6 0.6 0.6 0 6 0.7 0 7 0 7 0.7 0.8 0 8 0 8 0.8 400 400 400 400 500 500 500 500 600 600 600 600 700 700 700 700 800 800 800 800 Wavelength (nm) Voltage / V J sc (mAcm -2 ) V oc (V) η (%) Dye FF 17.43 0.680 0.71 8.42 JK-51 15.56 0.626 0.70 6.88 JK-52 J. Ko et. al. J. Photochem. Photobiol. A Chem. 2009, 201 , 102-110 Center for Next Generation Dye-sensitized Solar Cells

Indolo[1.2-f]phenanthridine dyes CN N S S COOH JK-60 JK 60 N S S E 0- Dye λ abs /nm (ε/M -1 cm -1 ) E ox /V E LUMO /V 0 /V COOH JK-60 (soild) JK 60 (soild) NC NC 339 (39 400) 453 (22 600) 339 (39 400), 453 (22 600) 1 01 1.01 2.33 2 33 -1.32 1 32 JK-61 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

Indolo[1.2-f]phenanthridine dyes J-V curves IPCE λ abs E LUMO a , nm d , J sc , mAcm -2 E ox E 0-0 V oc , V FF η (%) b , V c , V Dye ( ε /dm 3 mol -1 cm -1 ) V 339 (39 400) JK-60 12.17 1.01 2.33 -1.32 0.69 0.73 6.22 453 (22 600) JK-61 15.81 411 (37 600) 1.09 2.19 -1.12 0.73 0.72 8.34 J. Ko et. al. Tetrahedron 2009, 65 , 5302-5307 Center for Next Generation Dye-sensitized Solar Cells

Encapsulated dye by Cyclodextrin J. Ko et. al. Angew. Chem. Int. Ed. 2009 , 48 , 5938-5941 Center for Next Generation Dye-sensitized Solar Cells

Encapsulated dye by cyclodextrin IPCE J-V curves 100 16 90 14 ty (mA/cm2) 80 12 70 JK-2 10 60 JK-2+DCA ) Current densit IPCE (% JK-2 bCD+JK-2 50 8 aCD+JK-2 JK-2+DCA 40 rCD+JK-2 6 aCD/JK-2 30 bCD/JK-2 4 rCD/JK-2 20 2 10 0 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 400 500 600 700 800 Voltage (V) Wavelength (nm) J sc (mAcm -2 ) V oc (V) η (%) Dye FF 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

Durability of β -CD/JK-2 16 14 14 - 2 J /mA cm J sc /mA cm 12 10 8 Ionic liquid electrolye (red line): 0.2 M iodine, 0 200 400 600 800 1000 800 0.5 M NMBI, 0.1 M GuNCS in PMII/EMINCS 750 V / V V oc /mV 700 (13/7). Quasi-soild-state electrolyte (blue 650 line): 0.1 M iodine, 0.5M NMBI, 0.6 M 600 0 200 400 600 800 1000 DMPII, 5 wt% PVDF-HFP in MPN. 0.80 0.75 FF FF 0.70 0.65 After 1000 h of light soaking 0.60 0 200 400 600 800 1000 8 Quasi-soild-state electrolyte Quasi soild state electrolyte 7 7 E/ % 6 The initial efficiency of 7.40% is slightly 5 4 decreased to 6.31% 0 200 400 600 800 1000 t / hr Ionic liquid electrolye q y Evolution of solar cell parameters with β- ith β E l ti f l ll t The initial efficiency of 5.93% is slightly CD/JK-2 during visible-light soaking (AM increased to 6.48%. 1.5G, 100 mW/cm 2 ) at 60 ℃ . A 420 nm cut- off filter was put on the cell surface during ill illumi-nation. i ti J. Ko et. al. Angew. Chem. Int. Ed. 2009 , 48 , 5938-5941 Center for Next Generation Dye-sensitized Solar Cells

Organic Dyes: Organic Dyes: Efficiency Efficiency improvement improvement 100 IPCE IPCE 50 50 11 % 15 % 0 300 300 600 600 900 900 wavelength (nm)