Polymer Solar Cells. Kim, JunYoung. November, 3 th, 2010

Transcription

1 Polymer Solar Cells November, 3 th, 2010 Kim, JunYoung oratory Electrical Engineering and Computer Science Seoul National University

2 Contents 1. Introduction Why Organic Solar Cell? Solar Efficiency 2. Organic Solar Cells Organic Solar Cell Principle, Performance Parameter, Materials Polymer Solar Cell Structure, Thermal Annealing, To Increase Efficiency Other research Area 3. Summary

3 Contents 1. Introduction Why Organic Solar Cell? Solar Efficiency 2. Organic Solar Cells Organic Solar Cell Principle, Performance Parameter, Materials Polymer Solar Cell Structure, Thermal Annealing, To Increase Efficiency Other research Area 3. Summary

4 Why Organic Solar Cells? Gavin Conibeer, Materials Today 10, 42 (2007) Conventional PV Expensive (50cent/kWh) Materials characteristics limit application field (rigid, heavy) OPV Low Cost (simple device structure and process) New applications (Light, Flexible, Semi-transparent)

5 Polymer Solar Cells Why Organic Solar Cells? Pros. - Low cost production (simple structure, solution based process) - mechanical flexibility - Light weight - Customizable on the molecular level - Low potential for negative environmental impact photo source: National Laboratory for Sustainable Energy Cons. - Lower power conversion efficiency - Short operation life time photo source: Konarka Technologies

6 Solar Cells Efficiency Recent Paper Power Conversion Efficiency Science 317, 222 (2007) 6.5% Nature photonics,oct, online 25 (2009) 6.1% Nat. photons 3, 649 (2009) 7.73% Si Based solar cell 25~30% efficiency market share : over 85% Organic Based solar cell 3~8%, World Record 7.73% efficiency market share : not yet Organic solar cells are about 10~15% efficiency requested to enter the market

7 Contents 1. Introduction Why Organic Solar Cell? Solar Efficiency 2. Organic Solar Cells Organic Solar Cell Principle, Performance Parameter, Materials Polymer Solar Cell Structure, Thermal Annealing, To Increase Efficiency Other research Area 3. Summary

8 Organic Solar Cell Principle Light absorption Exciton diffusion Exciton dissociation Charge collection

9 Organic Solar Cell Performance Parameter = = ) ( ) ( )) ( (1 ) ( ) ( λ λ λ λ η λ λ λ λ λ λ um coll um SC SC SC d qf R d J d J I 1] ln[ 0 + = I I q nkt V SC OC OC SC m m V I V I FF = 100 = = = input OC SC input m m input m P FF V J P V I P P PCE

10 Organic Solar Cell - Materials Small Molecular Polymer Doner Accepter Doner Accepter CuPC C 60 P3HT PCBM ZnPC PTCDI PCPDTBT - SubPC - TiOPC - SBTBT - PBDTTT-CF -

11 Polymer Solar Cell Structure First breakthrough

12 Polymer Solar Cells - Thermal Annealing Effect Second breakthrough Thermal annealing Annealing time (min) Efficiency (%) Reference Saiciftci (2005) Yang Yang (2005) 15 3 Bradelt (2005) 30 5 Heeger (2005) increase Light absorption Jsc PCE

13 Polymer Solar Cell (P3HT:PCBM) Our Lab Device Structure 2.3eV Energy level LiF/Al P3HT:PCBM MoO 3 ITO ITO 4.8eV MoO 3 5.3eV 3.3eV 3.7eV P3HT : PCBM 5.2eV 6.1eV 4.3eV Al LiF Thermal annealing 150 C, 30min Jsc (ma/cm 2 ) 9.01 Voc (V) 0.56 FF (%) PCE (%) 3.64

14 To Increase Power Conversion Efficiency? Materials Synthesis Voc increase P3HT 1.9 ev PtTBT 1.85 ev PtTEBT 2.02 ev PtTVBT 1.86 ev PCBM - 6.1

15 To Increase Power Conversion Efficiency? Materials Synthesis Jsc increase Yang Yang.etal., nat.photons, 3, 649 (2009)

16 Optical Effect To Increase Power Conversion Efficiency? J.Y.K. etal., Adv. Mater, 18, 572 (2006)

17 Tandem Structure To Increase Power Conversion Efficiency? Bottom cell Top cell MoO ITO 5.3 MDMO-PPV 3.0 P3HT PCBM MoO 3 ZnPC Al:LiF C BCP 4.2 Al LiF Inter-electrode 7.0 (Energy, ev)

18 To Increase Power Conversion Efficiency? J.Y.K. etal., Science, 317, 222 (2007)

19 Other Research Area Flexible Solar Cells M. E. Thompson.etal., Acs Nano, 4, 2856 (2010)

20 Other Research Area All Solution Process C. J. Brabec.etal., Adv. Mater, 19, 3973 (2007)

21 Application Our Lab Structure : ITO/MoO3 (10 nm)/p3ht:pcbm (~120 nm)/lif (0.5 nm)/al (100 nm) 1. Electric fan under a Solar simulator (100 mw/cm2) 2. Electronic calculator under a Fluorescent lamp

22 Contents 1. Introduction Why Organic Solar Cell? Solar Efficiency 2. Organic Solar Cells Organic Solar Cell Principle, Performance Parameter, Materials Polymer Solar Cell Structure, Thermal Annealing, To Increase Efficiency Other research Area 3. Summary

23 Summary - organic solar cells have been studied intensively since they can be fabricated with low cost, simple processes such as spin-coating, screen printing or roll-to-roll coating not only on glass substrate but also on flexible substrates such as plastics or stainless foils - Organic solar cells are about 10~15% efficiency requested to enter the market (Organic Based solar cell 3~8%, World Record 7.73% efficiency )