Tanujjal Bora Tanujjal Bora Examination Committee: Prof. Joydeep Dutta Dr. Nitin Afzulpurkar Dr. Weerakorn Ongsakul g Microelectronics Microelectronics School of Engineering and Technology 1
Introduction Lit Literature Review t R i Methodology Results and Discussion Conclusions Conclusions 2
Energy Sources Nonrenewable Renewable • Wind • Oil • Coal • Biomass • Natural Gas • Solar Why Solar Why Solar Energy? • Abundant Available ~ 86,000 TW/y World Consumption ~ 15 TW/y • Never Ending Never Ending 3
� Photovoltaic Effect – Invented by Edmund Becquerel in1839 � 1 st Solar Cell was made in 1883 by Charles Fritts using Selenium � 1 Solar Cell was made in 1883 by Charles Fritts using Selenium � In 1954 – Commercial Solar Cell based on Single Silicon Crystal 2 nd Generation 3 rd Generation 1 st Generation 4 th Generation Multi Layer Thin Film Single Layer g y Polymer & Multi Polymer & Multi PN Junction Solar Cell PN Junction Junction Solar Cell • Polycrystalline • Dye Sensitized • Monocrystalline Si Si Solar Cell Solar Cell Si Si • Amorphous Si • Organic Polymer • CIGS Solar Cell • CdTe • Quantum Dot • GaAs Solar Cell 4
Invented by Michael Grätzel & Brian O’Regan in 1990 at EPFL, Switzerland y g • Simple to Fabricate • Low Cost of Manufacturing 5
Photoelectrode (PE) Dye Molecules Counter Electrode (CE) Electrolyte Counter Electrode (+) Dye Molecule Electrolyte (I - /I 3 - ) 3 Pt Catalyst Metal Oxide Semiconductor (TiO 2 /ZnO/SnO 2 ) Photo Electrode ( ‐ ) 6
Similar to Natural Photosynthesis CH 2 O + O 2 H 2 O e ‐ CB LUMO + e ‐ S + e ‐ e E F CO 2 Energy Maximum e ‐ Voltage e - e - e ‐ Ox/Re E F e - Redox ‐ Couple p S/S * h ν h ν S/S HOMO Dye Electron Electron Chlorophyll Donor Acceptor h + h ν VB Back- Semiconductor Counter Hole Conducting Contact h ν Electrode h ν Medium 7
Higher Surface Area => Higher Dye Adsorption Charge Hopping g pp g e e Poro s Thin Film Porous Thin Film e e e e e e e - - - - - Zinc Oxide Thin Film Direct Path Nanorods e - e - e - e - e - e - Zinc Oxide Nanorod Nano < 100 nm 8
Maximum DSSC Maximum DSSC Photoelectrode Structure Synthesis Method Type of Dye used Efficiency Material Reported (%) Porous Thin ZnO Spin Coating N719 5 Film Film ZnO Nanowire Hydrothermal N3 2.4 Branched ZnO MOCVD N719 1.1 Nanowire Nanowire Mixture of ZnO Nanoparticle Hydrothermal Mercurochrome 3.2 and Nanorods ZnO ZnO Nanosheets Nanosheets Spray Pyrolysis Spray Pyrolysis N719 N719 3 9 3.9 ZnO Nanotube CVD + Pyrolysis N719 4.6 K. Keis, C. Bauer, G. Boschloo, A. Hagfeldt, K. Westermark, H. Rensmo, H. Siegbahn. Journal of Photochemistry and Photobiology A: Chemistry 2002;148(1 ‐ 3):57 ‐ 64. M. Guo, P. Diao, X. Wang, S. Cai. Journal of Solid State Chemistry 2005;178(10):3210 ‐ 3215. K. Kakiuchi, E. Hosono, S. Fujihara. Journal of Photochemistry and Photobiology A: Chemistry 2006;179(1 ‐ 2):81 ‐ 86. C. H. Ku, J. J. Wu. Nanotechnology 2007;18(50) J. B. Baxter, E. S. Aydil. Solar Energy Materials and Solar Cells 2006;90(5):607-622 E. Hosono, S. Fujihara, I. Honma, H. Zhou. Advanced Materials 2005;17(17):2091-2094 9
Construct ZnO Nanorods based DSSC Improve Electron Conduction 10
Hydrothermal Growth of ZnO Nanorods 1 μ m Anisotropic Agglomeration of ZnO Nanorods Seeds Zinc nitrate + hexamine Zi it t h i Annealed at 350 o C Zinc nitrate + hexamine at for 1 Hour 90 ⁰ C A. Sugunan, H. C. Warad, M. Boman , J. Dutta, Journal of Sol-Gel Science and Technology, vol. 39, no. 1 SPEC. ISS., pp. 49-56, 2006. S. Baruah, and J. Dutta, Science and Technology of Advanced Materials, vol. 10, no. 013001, pp. 18pp, 2009. S. Baruah, and J. Dutta, Journal of Crystal Growth, vol. in press, 2009. 11
Simple Simple Ease of Fabrication Low Cost Low Cost Electrolyte Surlyn Counter Electrode Counter Electrode Photoelectrode 12
Normalized Adsorption of Dye on ZnO Nanorods Absorption Spectra of Dye on ZnO NRs at various Sensitization Time at various Dye Sensitization Times 3.0 1.4 1 hours nm 2 hours 2 hours orption at λ = 580 n 2 2.5 1.2 3 hours 4 hours 5 hours 1.0 2.0 10 hours 20 hours rbance 0.8 24 hours 48 hours 1.5 0.6 72 h 72 hours Abso Normalized Adso Maximum 0.4 1.0 Dye 0.2 Adsorption 0.5 0.0 -0.2 0.0 300 400 500 600 700 800 900 0 20 40 60 80 Wave Length (nm) Sensitization Time (Hours) Ma im m Light Absorption Maximum Light Absorption = 24 Hours 24 Ho rs 13
Nonhierarchical Nonhierarchical Hierarchical Hierarchical Growth Growth ZnO Nanorods from ZnO Nanorods from Primary Growth Secondary Growth y Conducting Glass (FTO ) Conducting Glass (FTO ) 1 µm 1 µm 14
Maximum SA = 483.47 cm 2 Variation in Surface Area of the ZnO Nanorod Photoelectrode 20 mM with Precursor Concentration and Growth Time 10 Hours 1 µm 600 10 mM 15 mM 500 2 ) Area (cm 20 mM 25 mM 400 30 mM 20 mM 20 M Surface A 300 300 40 Hours 200 ) 120 s 100 r u 100 o H ( 0 80 e 1 µm m 30 i T 60 h h 25 25 P Precursor Concentration (mM) t t w 40 o 20 r G 15 20 l a t o 10 T 0 5 20 mM 60 Hours 1 µm 15
Variation in Short Circuit Current Density (J SC ) of the DSSC with increasing Surface Area of the Photoelectrode g 2.5 2.0 1 5 1.5 J SC (mA/cm 2 ) 1.0 0.5 0.0 0 100 200 300 400 500 Surface Area (cm 2 ) Surface Area Surface Area Short Circuit Current (J ) Short Circuit Current (J sc ) 16
FF = Maximum Power DSSC IV Characteristics 12 Theoretical Power Jsc 10 = I max X V max Voc = 0.67 V sity (mA/cm 2 ) X 100% Jsc = 11 mA/cm2 I sc X V oc FF = 72.40% 8 η = 5.34% Current Dens 6 6 Maximum Power 4 η = In put Power In put Power 2 Active Area 0.09 cm 2 = I sc X V oc X FF Voc 0 % P in 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 in Voltage (V) 17
e - LUMO of Dye LUMO of Dye e - e - � Better Charge Separation e - SPR level CB ZnO � Low Dielectric Constant of Au HOMO of Dye h + h Gold Nanoparticle 16 Active Area = 0.09 cm 2 cm 2 ) 14 t Density, J SC (mA/ 12 10 V OC = 0.67 V J SC = 11 mA/cm 2 8 FF = 72.40 % % hort Circuit Current η = 5.34 % V OC = 0.67 V 6 J SC = 14.89 mA/cm 2 4 FF = 65.06 % η = 6.49 % With Au Nanoparticles 2 Without Au Nanoparticles S 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Voltage (V) 18
� Ink Jet Printed Silver (Ag) Grid Lines on the Counter Electrode � I k J t P i t d Sil (A ) G id Li th C t El t d Silver Grid Lines 19
DSSC I-V Characteristics with and without Ag grid lines 2.5 Active Area = 1 cm 2 V V OC = 0.62V 0 62V nt Density (mA/cm 2 ) ) 2.0 J SC = 2.3 mA/cm 2 FF = 45.06 % Active Area = 1 cm 2 η = 0.64 % 1.5 V OC = 0.52 V J SC = 2.14 mA/cm 2 FF = 39.82 % Photocurren η = 0.44 % 1 0 1.0 0.5 With Ag grid lines Without Ag grid lines 0 0 0.0 0.0 0.2 0.4 0.6 Voltage (V) Sheet Resistance Sheet Resistance Fill Factor Fill Factor 20
� DSSC Efficiency at Optimum ZnO Nanorod growth condition is 5.34% � Using Gold (Au) Nanoparticles, DSSC Efficiency is 6.49% � Ink Jet Printed Silver (Ag) Grid Lines can Improve Fill Factor 21
Prof. Joydeep Dutta for his continuous Guidance, Valuable Suggestions and Encouragements Dr. Nitin Afzulpurkar and Dr. Weerakorn Ongsakul for their Valuable Advices and Supports Supports Sincere Gratitude to all the AIT Nano Lab Members – Mr. S. Baruah, Mr. R. Kitsomboonloha, Mr. Myo Myint Tay Zar, Md. Abbas Mahmood, Mrs. I. Baruah – f for their Help and Suggestions th i H l d S ti Special Homage to My Family and Friends for their Love, Support and Sacrifices 22
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