The Columbia EFRC: Redefining Photovoltaic Efficiency...

file: Lenfest Symp 05-04-10 rev b.ppt

Tony Heinz

Jim Yardley

Louis Brus

The Columbia EFRC: Redefining Photovoltaic Efficiency Through Molecule-Scale Control.

James YardleyElectrical Engineering

file: EFRC Program Summary 3-16-10 rev h.ppt

EFRC Origins: Basic Research Needs.


Energy Frontier Research Centers: Genesis.

Total Resources: $770 million over 5 years!


EFRC: History and Basis


The EFRC Network.


• 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 technologywill not bridge the gap- Conceptual breakthroughs are needed that come

only from high risk-high payoff basic research

• Interdisciplinary research is requiredphysics, chemistry, biology, materials, nanoscience

• Basic and applied science should couple seamlessly http://www.sc.doe.gov/bes/reports/abstracts.html#SEU

Basic Research Needs for Solar Energy.


Solar Cell Evolution.

Shockley-Queisser Limit

“Organic Photovoltaics”


Opportunitiesinexpensive 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

polymer donorMDMO-PPV

O

O

()n

fullerene acceptorPCBM O

OMeO

OMe

donor-acceptor junction

Source: George Crabtree, Solar EnergyChallenges and Opportunities

Organic Photovoltaics: Plastic Photocells.


Columbia Energy Frontier Research Center

DOE Funding:$16 million over 5 years.

Sept. 1, 2009 start.

Columbia UniversityColumbia Nanocenter Brookhaven National Lab.

Center for Functional NanomaterialsMark HybertsenCharles Black

University of ArkansasXiaogang Peng

Purdue UniversityAshraf Alam

Univ. of TexasXiaoyang Zhu

General ElectricLoucas Tsakalakos

HelioVoltLouay Eldada

IBMGeorge Tulevski

Tel Aviv Univ.Eran Rabani

Partners (EFRC funded)CollaboratorsPartners (Government)

State of New YorkNYSTARNYSERDASmart Grid Consortium


Columbia EFRC: Research Team.

Columbia University Principal InvestigatorsSimon Billinge, Applied PhysicsLouis Brus, ChemistryGeorge Flynn, ChemistryTony Heinz, Electrical EngineeringIrving P. Herman, Applied PhysicsJames Hone, Mechanical EngineeringPhilip Kim, PhysicsIoannis Kymissis, Electrical EngineeringColin Nuckolls, ChemistryRichard Osgood, Electrical EngineeringDavid Reichman, ChemistryKenneth Shepard, Electrical EngineeringMike Steigerwald, ChemistryLatha Venkataraman, Applied PhysicsChee Wei Wong, Mechanical EngineeringJames Yardley, Electrical Engineering

Columbia University Seed Fund FacultyDirk Englund, Electrical EngineeringJonathan Owen, ChemistryAbhay Pasupathy, Physics

Principal Investigators at Partner InstitutionsAshraf Alam, Electrical Engineering, PurdueXiaogang Peng, Chemistry, Arkansas Univ.Xiaoyang Zhu, Chemistry, Univ. Texas, Austin

Ashraf Alam Xiaoyang Zhu Xiaogang Peng


Columbia EFRC: Research Team… Cont.

External Collaborators (Unfunded)Charles Black, Brookhaven, CFNMark S. Hybertsen, Brookhaven, CFNEran Rabani, Chemistry, Tel Aviv University

Charles BlackMark Hybertsen

Eran Rabani

EFRC Research FellowsTheanne Schiros, EFRC, Columbia Univ.Jonathan Schuller, EFRC, Columbia Univ.

Jonathan Schuller

Theanne Schiros


Re-Defining Photovoltaic Efficiency Through Molecule Scale Control

OVERALL RESEARCH PLAN AND DIRECTIONSFundamental 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.

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.

an Office of Basic Energy SciencesEnergy Frontier Research Center


Columbia EFRC Research Thrusts.

Re-Defining Photovoltaic Efficiency Through Molecule Scale Control.


THRUST 1. FUNDAMENTALS OF CHARGE GENERATION: EXCITATION, SEPARATION, AND EXTRACTION OF CHARGE CARRIERS.Thrust Leader: Colin Nuckolls


New Materials for Efficient Charge Extraction

Engineered Quantum DotsXiaogang Peng (U Ark)Simon BillingeJonathan OwenWith Chee Wei Wong, Mike Steigerwald, Louis Brus

Molecular Clusters for Photovoltaic Cells.Michael SteigerwaldJonathan OwenWith Latha Venkataraman

Organic Semiconductors and Nanostructures.Colin NuckollsIoannis KymissisWith Jonathan Owen, Mike Steigerwald

Program Goal: Develop and engineer new materials that promote efficient extraction of electron and hole from single exciton.

Ni23Se12(PEt3)13


Direct map of electron flow.

Fundamentals of Charge Transport Across Interfaces.

Transport Across Molecular Junctions.Latha VenkataramanMark Hybertsen (BNL)Mike Steigerwald

Transport Across Interfaces.George FlynnAbhay PasupathyRichard OsgoodXiaoyang Zhu (U Tex.)

Program goal: Determine the atomic-scale factors controlling the efficiency and energetics of charge transfer at materials of interest for nanosolar systems.


Optical Nanostructures for Efficient Light Collection.

Nanostructured Antennas.Richard OsgoodDirk EnglundWith Chee Wei Wong

Light Trapping in Thin Films.Dirk EnglundWith Chee Wei Wong

Program goal: Develop integrated optical devices and structures that optimize coupling of solar radiation with nanostructured solar devices.


THRUST II. CHARGE COLLECTION: TRANSPORT AT THE NANOSCALE AND BEYOND.Thrust Leader: Ioannis Kymissis


Nanostructured Heterojunction Solar Devices.

Ioannis KymissisCharles Black (BNL)Ashrafel Alam (Purdue)With Colin Nuckolls, Ken Shepard, Philip Kim, Irving Herman

Program Goal: Develop, understand, and evaluate heterostructuresolar devices with efficient extraction of charge carriers.

p

n

Idea: Engineer surface energy for control of organic blend phase separation.

PDMS molding followed by microcontactprinting of surface modifying silanes


Self-Assembled Heterostructure Devices.

Colin NuckollsIoannis KymissisWith Charles Black (BNL), Colin Nuckolls, Ken Shepard, Philip Kim

Program Goal: Develop and understand heterostructure devices built upon nanoscale self-assembly.


New Concepts for Organic Solar Cell Devices.Photovoltaic Universal Joints: Ball-and-Socket Interfaces in Molecular Photovoltaic Cells.

Colin NuckollsIoannis KymissisNoah TremblayAlon GorodetskyMarshall CoxTheanne SchirosMichael Steigerwald

Funded in part by the National Science Foundation under NSF Award Number CHE-0641523, 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-SC0001085, 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).

(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 C60 (bottom).

Shape Complementary Molecular Photovoltaics.

electrode 1

electrode 2

n-type semiconductor p-type n-type

shape-complemenarity

Interdigitated columns

assembly

p-type semiconductor

HBC/C60 bilayer devices show good functional performance!Voc=0.95 V, η= 5.7% (UV), > 1% (amb. solar)Voc 10x’s larger for contorted- vs. flat- HBC devices (under UV light).

Goal: ordered bulkheterojunction.Approach: exploit physical & electronic complementarity of C60 with contorted-HBC(hexabenzocoronene)


Carbon-based Conductor and Semiconductors.

Philip KimTony HeinzWith Ioannis Kymissis, Charles Black (BNL), Ken Shepard.

Simplified band diagram (shown at Voc) of a P3HT:PCBM solar cell having PEDOT and Al contacts.

Graphene work function is controllable through chemical doping and through applied electric fields.

Conventional solar cells need work functions matched to materials.

Program Goal: Develop carbon-based electrode structures for high efficiency charge extraction from nanostructured heterojunction devices.

Band offsets are major source of loss!


THRUST 3. CARRIER MULTIPLICATION: BEYOND THE SHOCKLEY-QUEISSER LIMIT.Thrust Leader: David Reichman


Theoretical Basis for Carrier Multiplication.

Program Goal: Develop broadly-based theoretical model for understanding multiple carrier generation in semiconducting materials including quantum dots, carbon nanotubes, and molecular clusters.

• Increase PV efficiency about 40% above S-Q limit.

• Need strong electron-electron interactions.

David ReichmanMark Hybertsen (BNL)Eran Rabani (Tel Aviv)


MEG in One-Dimensional Systems.

Tony HeinzLouis BrusJames Hone

(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.

Research Plan

Absorption Spectrum of Individual (21,21) Armchair Metallic Nanotube

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