The Columbia EFRC: Redefining Photovoltaic Efficiency Through Molecule-Scale Control. James Yardley Electrical Engineering. Tony Heinz.

Transcription

1 The Columbia EFRC: Redefining Photovoltaic Efficiency Through Molecule-Scale Control. James Yardley Electrical Engineering Tony Heinz Louis Brus Jim Yardley file: Lenfest Symp rev b.ppt Page 1

2 EFRC Origins: Basic Research Needs. file: EFRC Program Summary rev h.ppt Page 2

3 Energy Frontier Research Centers: Genesis. Total Resources: $770 million over 5 years! file: EFRC Program Summary rev h.ppt Page 3

4 EFRC: History and Basis file: EFRC Program Summary rev h.ppt Page 4

5 The EFRC Network. file: EFRC Program Summary rev h.ppt Page 5

6 Basic Research Needs for Solar Energy. The Sun is a singular solution to our future energy needs - capacity dwarfs fossil, nuclear, wind... - sunlight delivers more energy in one hour than the earth uses in one year - free of greenhouse gases and pollutants - secure from geo-political constraints Enormous gap between our tiny use of solar energy and its immense potential - Incremental advances in today s technology will not bridge the gap - Conceptual breakthroughs are needed that come only from high risk-high payoff basic research Interdisciplinary research is required physics, chemistry, biology, materials, nanoscience Basic and applied science should couple seamlessly file: Lenfest Symp rev b.ppt Page 6

7 Solar Cell Evolution. Shockley-Queisser Limit Organic Photovoltaics file: Lenfest Symp rev b.ppt Page 7

8 Organic Photovoltaics: Plastic Photocells. ( O O ) n polymer donor MDMO-PPV fullerene acceptor PCBM O OMe donor-acceptor junction Opportunities inexpensive materials, conformal coating, self-assembling fabrication, wide choice of molecular structures, cheap solar paint Challenges low efficiency (2-5%), high defect density, low mobility, full absorption spectrum, nanostructured architecture Source: George Crabtree, Solar EnergyChallenges and Opportunities file: Lenfest Symp rev b.ppt Page 8

9 Columbia Energy Frontier Research Center Columbia University Columbia Nanocenter Tel Aviv Univ. Eran Rabani General Electric Loucas Tsakalakos Brookhaven National Lab. Center for Functional Nanomaterials Mark Hybertsen Charles Black University of Arkansas Xiaogang Peng HelioVolt Louay Eldada IBM George Tulevski State of New York NYSTAR NYSERDA Smart Grid Consortium Purdue University Ashraf Alam Univ. of Texas Xiaoyang Zhu Partners (EFRC funded) Collaborators Partners (Government) DOE Funding: $16 million over 5 years. Sept. 1, 2009 start. file: Lenfest Symp rev b.ppt Page 9

10 Columbia EFRC: Research Team. Columbia University Principal Investigators Simon Billinge, Applied Physics Louis Brus, Chemistry George Flynn, Chemistry Tony Heinz, Electrical Engineering Irving P. Herman, Applied Physics James Hone, Mechanical Engineering Philip Kim, Physics Ioannis Kymissis, Electrical Engineering Colin Nuckolls, Chemistry Richard Osgood, Electrical Engineering David Reichman, Chemistry Kenneth Shepard, Electrical Engineering Mike Steigerwald, Chemistry Latha Venkataraman, Applied Physics Chee Wei Wong, Mechanical Engineering James Yardley, Electrical Engineering Columbia University Seed Fund Faculty Dirk Englund, Electrical Engineering Jonathan Owen, Chemistry Abhay Pasupathy, Physics Principal Investigators at Partner Institutions Ashraf Alam, Electrical Engineering, Purdue Xiaogang Peng, Chemistry, Arkansas Univ. Xiaoyang Zhu, Chemistry, Univ. Texas, Austin Ashraf Alam Xiaoyang Zhu Xiaogang Peng file: Lenfest Symp rev b.ppt Page 10

11 Columbia EFRC: Research Team Cont. External Collaborators (Unfunded) Charles Black, Brookhaven, CFN Mark S. Hybertsen, Brookhaven, CFN Eran Rabani, Chemistry, Tel Aviv University EFRC Research Fellows Theanne Schiros, EFRC, Columbia Univ. Jonathan Schuller, EFRC, Columbia Univ. Charles Black Mark Hybertsen Theanne Schiros Eran Rabani Jonathan Schuller file: Lenfest Symp rev b.ppt Page 11

12 The Columbia EFRC will create enabling technology to re-define efficiency in nanostructured thin-film organic photovoltaic devices through fundamental understanding and through molecule-scale control of charge formation, separation, extraction, and transport. Re-Defining Photovoltaic Efficiency Through Molecule Scale Control OVERALL RESEARCH PLAN AND DIRECTIONS Fundamental understanding of photo-physical and kinetic properties on the nanoscale will allow us to design systems for efficient photovoltaic generation and separation of charges. By using new conducting materials such as graphene we can transport these charges to macroscopic electrical systems, providing basis for revolutionary low cost, high efficiency devices. an Office of Basic Energy Sciences Energy Frontier Research Center file: Lenfest Symp rev b.ppt Page 12

13 Columbia EFRC Research Thrusts. Re-Defining Photovoltaic Efficiency Through Molecule Scale Control. file: Lenfest Symp rev b.ppt Page 13

14 THRUST 1. FUNDAMENTALS OF CHARGE GENERATION: EXCITATION, SEPARATION, AND EXTRACTION OF CHARGE CARRIERS. Thrust Leader: Colin Nuckolls file: Lenfest Symp rev b.ppt Page 14

15 New Materials for Efficient Charge Extraction Engineered Quantum Dots Xiaogang Peng (U Ark) Simon Billinge Jonathan Owen With Chee Wei Wong, Mike Steigerwald, Louis Brus Molecular Clusters for Photovoltaic Cells. Michael Steigerwald Jonathan Owen With Latha Venkataraman Organic Semiconductors and Nanostructures. Colin Nuckolls Ioannis Kymissis With Jonathan Owen, Mike Steigerwald Ni 23 Se 12 (PEt 3 ) 13 Program Goal: Develop and engineer new materials that promote efficient extraction of electron and hole from single exciton. file: Lenfest Symp rev b.ppt Page 15

16 Fundamentals of Charge Transport Across Interfaces. Transport Across Molecular Junctions. Latha Venkataraman Mark Hybertsen (BNL) Mike Steigerwald Transport Across Interfaces. George Flynn Abhay Pasupathy Richard Osgood Xiaoyang Zhu (U Tex.) Direct map of electron flow. Program goal: Determine the atomic-scale factors controlling the efficiency and energetics of charge transfer at materials of interest for nanosolar systems. file: Lenfest Symp rev b.ppt Page 16

17 Optical Nanostructures for Efficient Light Collection. Nanostructured Antennas. Richard Osgood Dirk Englund With Chee Wei Wong Light Trapping in Thin Films. Dirk Englund With Chee Wei Wong Program goal: Develop integrated optical devices and structures that optimize coupling of solar radiation with nanostructured solar devices. file: Lenfest Symp rev b.ppt Page 17

18 THRUST II. CHARGE COLLECTION: TRANSPORT AT THE NANOSCALE AND BEYOND. Thrust Leader: Ioannis Kymissis file: Lenfest Symp rev b.ppt Page 18

19 Nanostructured Heterojunction Solar Devices. Ioannis Kymissis Charles Black (BNL) Ashrafel Alam (Purdue) With Colin Nuckolls, Ken Shepard, Philip Kim, Irving Herman Idea: Engineer surface energy for control of organic blend phase separation. p n PDMS molding followed by microcontact printing of surface modifying silanes Program Goal: Develop, understand, and evaluate heterostructure solar devices with efficient extraction of charge carriers. file: Lenfest Symp rev b.ppt Page 19

20 Self-Assembled Heterostructure Devices. Colin Nuckolls Ioannis Kymissis With Charles Black (BNL), Colin Nuckolls, Ken Shepard, Philip Kim Program Goal: Develop and understand heterostructure devices built upon nanoscale self-assembly. file: Lenfest Symp rev b.ppt Page 20

21 New Concepts for Organic Solar Cell Devices. Photovoltaic Universal Joints: Ball-and-Socket Interfaces in Molecular Photovoltaic Cells. Colin Nuckolls Ioannis Kymissis Noah Tremblay Alon Gorodetsky Marshall Cox Theanne Schiros Michael Steigerwald (A) Depiction of ball-and-socket interfaces in bilayer and bulk heterojunction devices. (B) The chemical structure of the contorted-hbc. (C) Correlation between depiction (top) and molecular structure from the co-crystal of HBC and C 60 (bottom). Funded in part by the National Science Foundation under NSF Award Number CHE , in part from the Center for Re-Defining Photovoltaic Efficiency Through Molecule Scale Control, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC , and in part from the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, US D.O.E. (#DE-FG02-01ER15264) and US D.O.E. (#DE-FG02-04ER46118). file: Lenfest Symp rev b.ppt Page 21

22 Shape Complementary Molecular Photovoltaics. electrode 1 n-type semiconductor p-type semiconductor electrode 2 p-type n-type assembly shapecomplemenarity Interdigitated columns Goal: ordered bulk heterojunction. Approach: exploit physical & electronic complementarity of C 60 with contorted-hbc (hexabenzocoronene) HBC/C 60 bilayer devices show good functional performance! V oc =0.95 V, η= 5.7% (UV), > 1% (amb. solar) V oc 10x s larger for contorted- vs. flat- HBC devices (under UV light).

23 Carbon-based Conductor and Semiconductors. Philip Kim Tony Heinz With Ioannis Kymissis, Charles Black (BNL), Ken Shepard. Conventional solar cells need work functions matched to materials. Graphene work function is controllable through chemical doping and through applied electric fields. Simplified band diagram (shown at V oc ) of a P3HT:PCBM solar cell having PEDOT and Al contacts. Band offsets are major source of loss! Program Goal: Develop carbon-based electrode structures for high efficiency charge extraction from nanostructured heterojunction devices. file: Lenfest Symp rev b.ppt Page 23

24 THRUST 3. CARRIER MULTIPLICATION: BEYOND THE SHOCKLEY-QUEISSER LIMIT. Thrust Leader: David Reichman file: Lenfest Symp rev b.ppt Page 24

25 Theoretical Basis for Carrier Multiplication. David Reichman Mark Hybertsen (BNL) Eran Rabani (Tel Aviv) Increase PV efficiency about 40% above S-Q limit. Need strong electronelectron interactions. Program Goal: Develop broadly-based theoretical model for understanding multiple carrier generation in semiconducting materials including quantum dots, carbon nanotubes, and molecular clusters. file: Lenfest Symp rev b.ppt Page 25

26 MEG in One-Dimensional Systems. Tony Heinz Louis Brus James Hone Research Plan Absorption Spectrum of Individual (21,21) Armchair Metallic Nanotube (a) Scanning electron micrograph of an individual SWNT with electrode contacts. (b) - (d) Fabrication of split gates to produce a controlled p-n junction. (e) Photocurrent and Rayleigh scattering spectrum. file: Lenfest Symp rev b.ppt Page 26