Research Highlights Theme II: Energy Conversion – Solar Energy

Research Highlights Theme II: Energy Conversion

– Solar Energy to Electricity & Fuels Theme II Leader

and Co-PI

Jun Li

Associate Professor Department of Chemistry, Kansas State University

Manhattan, KS 66506-3701

[email protected]

June 13, 2011

2nd EPSCoR Annual Review Meeting, Manhattan, KS

• Investigating novel devices and architectures that are used to convert solar energy into electricity or fuels with cost/efficiency balanced performance.

• Three areas are explored: – 1) improvement in materials and characterization, – 2) innovation in device architecture and design, – 3) exploration of breakthrough systems for highly efficient energy conversion.

• Interactions with other themes:

– Theme I: to apply materials and new concepts derived from theme I in • the new synthetic broadband photovoltaic materials or isolated natural

photosynthesis molecules onto new PV architectures • catalysts for watersplitting and CO2 reduction

– Theme IV: system assessment of the cost, efficiency, and environmental impact of the potential technologies.

Theme II: Energy Conversion – Solar Energy to Electricity & Fuels

Objectives

Theme II: Funded Research Activities in FY2010

• The understanding of the fundamental physics and chemistry of nanomaterials and nanodevices toward novel energy conversion concepts:

– Hui Zhao (KU, 1.0 GRA): “Nonequilibrium carrier transport in carbon-based nanomaterials”

– Cindy Berrie (KU, 1.0 GRA): “Interfacial Characterization of DSSC Components”

• The development of cost/performance balanced PV technology through nanoengineering novel nanostructures:

– Judy Wu (KU. 1.0 GRA): “Manipulating photons and electronics at nanoscale for high efficiency thin film solar cells”

– Jun Li (KSU, 1.0 GRA): “Vertical core-shell nanowire arrays based on carbon nanofiber templates as DSSC and energy storage architecture”

• The development of catalysts for fuel production by watersplitting and CO2 reduction:

– Kenneth J. Klabunde (KSU, 0.5 GRA): “Photocatalytic Water Splitting: Hydrogen and Oxygen Production Using Visible Lights”.

– Paul Rillema (KSU, 1.0 GRA): “Synthesis and Photochemical properties of Re(I) and Re(II) Solar Sensitizer Dyes for Converting Solar Energy to Electric Power and Catalytic Reduction of CO2 into Higher Energy Products”

Total funded GRAs: 5.5 Amount: $20,600 (salary) + 1,000 (travel) + $7,000 (consumables) = $28,600/GRA

Funded Projects:

Nonequilibrium carrier transport in carbon-based nanomaterials

Objective: To develop high resolution laser techniques to

study charge transport in semiconductors. To study diffusive transport of charge carriers

in graphene and other materials. To explore ways of using graphene to improve

efficiency of solar cells.

Link with other EPSCoR projects: Using graphene as electrodes in dye-

sensitized solar cells and other types of solar cells.

People involved: Senior Participant: Hui Zhao Participant:

Brian Ruzicka, Lalani Werake, Nardeep Kumar, Ben Weintrub (undergraduate)

Collaborators: (* outside EPSCoR team) Judy Wu, Cindy Berry, Jun Li, Francis D’Souza, Kian-Ping Loh*

What have been accomplished: High resolution laser techniques developed. Diffusion and energy relaxation of charge carriers in graphene understood. Collaboration established and joint proposals developed and submitted. What to be done: Ballistic transport of charge carriers in graphene Electronic and optical properties of BCN and BN films

Pump

Probe

t = 0

t = τ

h e h e h

e h e

h e

h e h e h e

0

1

0

1

2

-20

2

∆T/T

0 (10-4

)

x (µm)

τ (ps)

0 100 200 300

101

102

103

104

D (c

m2 /s

)

Sample Temperature (K)

Epitaxial Graphene

Reduced Graphene Oxide

GaAs

Si

Nonequilibrium carrier transport in carbon-based nanomaterials (continued)

Publications: B.A. Ruzicka, S. Wang, L.K. Werake, B. Weintrub, K.P. Loh, and Hui Zhao.

Hot carrier diffusion in graphene. Physical Review B 2010, 82, 195414. B.A. Ruzicka, L.K. Werake, H. Samassekou, and Hui Zhao. Ambipolar

diffusion of photo-excited carriers in bulk GaAs. Applied Physics Letters 2010, 97, 262119.

B.A. Ruzicka, L.K. Werake, Hui Zhao, S. Wang, and K.P. Loh. Femtosecond pump-probe studies of reduced graphene oxide thin films. Applied Physics Letters 2010, 96, 173106.

B.A. Ruzicka, N. Kumar, S. Wang, K.P. Loh, and Hui Zhao. Two-probe study of hot carriers in reduced graphene oxide. Journal of Applied Physics 2011, 109, 084322.

H. Zhao and A.L. Smirl. Injection and detection of ballistic electrical currents in silicon. Applied Physics Letters 2010, 97, 212106.

E.J. Loren, Hui Zhao, and A. L. Smirl, All-optical injection and detection of ballistic charge currents in germanium. Journal of Applied Physics 2010, 108, 083111.

Other funding developed through the EPSCoR projects: “Hot carrier transport in graphene”, ACS Petroleum Research Funds (Doctoral

New Investigator), $100k, 09/01/2011 – 08/31/2013.

Additional significant activities/results/notes: Supervised one REU student.

Interfacial Characterization of DSSC Components Objective: To prepare high quality (high transmission, low

resistance) graphene films for potential use as conductive electrodes.

To create nanofabricated graphene films to optimize the properties.

Characterize the binding of dye with substrate

Approach

Link with other EPSCoR projects: New materials for incorporation in DSSC

(Francis D’Souza) New strategies for structuring materials for

DSSC (Jun Li) New dye materials (Francis D’Souza, Paul

Rillema)

People involved: PI: Cindy Berrie Participants: Christina Edwards, Greg Smith, Rudolfo Torres-Gavosto, Stephen Harrington, Ryan Murphy Collaborators: Judy Wu, Jianwei Liu, Caitlin Rochford

What has been accomplished: Characterization of graphene on differently structured Cu substrates shows dramatic influence of substrate on growth. Modification of graphene using NIL, anodic oxidation and chemical doping changes properties Optimization of TiO2 films Characterize model dye binding to TiO2 substrates

What to be done: Explore parameters and optimization of graphene growth Explore effect of varying size, spacing and doping levels Conductance of model dye systems, other dyes (collaboration)

CVD Graphene Films- Restructuring of Cu

Nanoimprint Array

Interfacial Characterization of DSSC Components (continued)

Publications: Liu, J.; Wu, J.; Edwards, C. M.; Berrie, C. L.; Moore, D.; Chen, Z.; Maroni, V.

A.; Paranthaman, M. P. ; Goyal, A.; “Triangular single crystalline graphene nucleation on rollling assisted biaxially textured copper substrates” (submitted)

Liu, J.; Xu, G.; Rochford, C.; Lu, R.; Wu, J. Edwards, C. M.; Berrie, C. L.; Chen, Z.; Maroni, V. A.; “Graphene photonic crystals for broadband flexible transparent conductors” (submitted)

Other funding developed through the EPSCoR projects: Co-Investigator on a number of submitted proposals including NSF Solar,

MURI, MIRT, STEM Co-Investigator in developing IGERT training program

Additional significant activities/results/notes: Presented 2 posters on EPSCoR research at ACS Regional Meeting in

Wichita, KS, 2010: Midwest Regional ACS Meeting Ryan P. Murphy, Stephen M. Harrington, Cindy L. Berrie

(presented by Ryan P. Murphy) “Structural Characterization of the dye-TiO2 interface for optimization of charge transport”

Midwest Regional ACS Meeting, Wichita KS Stephen M Harrington, Ryan P Murphy, Cindy L. Berrie (presented by Stephen Harrington) “Investigation of factors affecting interfacial charge transport in TiO2 based dye sensitized solar cells via scanning probe microscopy”

Submitted abstracts for two presentations at International AVS meeting

Vertical Core-shell Nanowire Arrays Based on Carbon Nanofiber Templates as DSSC and Energy Storage Architecture

Objective: To develop a new dye-sensitized solar cell

(DSSC) architecture based on TiO2 coating on vertically aligned carbon nanofiber array template

To understand the critical factors in DSSCs To Extend such materials for electrical energy

storage

Approach

Link with other EPSCoR projects: Theme II: interface characterization and

single nanowire device study (Judy Wu) Theme I: broadband dye (Francis D’Souza),

PSI hybrid (Ryszard Jankwiak), new dyes (Paul Rillema and Stefan Bossmann)

People involved: PI: Jun Li Participant:

Dr. Jianwei Liu, Jeremy Essner, Steven Klankowski

Collaborators: (* outside EPSCoR team) KU: Judy Wu, Caitlin Rochford, Fangli Wang

KSU: Ken Klabunde, Yenting Kuo Texas Tech: Hongxing Jiang*, Jingyu Lin* Catalyst Power Inc.: Ron Rodjeski

What have been accomplished: Materials processing for DSSC and supercapacitor established Desired materials structure and properties achieved DSSC and supercapacitor show promising performance Collaboration established

What to be done: Materials/processing optimization Systematic optimization of efficiency and energy/power density Explore new dyes and photosynthesis complex on DSSCs

DSSC schematic Cell characterization

Supercapacitor Charge-discharge curve

Vertical Core-shell Nanowire Arrays Based on Carbon Nanofiber Templates as DSSC and Energy Storage Architecture (continued)

Publications: Liu, J.; Kuo, Y.-T.; Klabunde, K. J.; Rochford, C.; Wu, J.; Li, J., Novel Dye-

Sensitized Solar Cell Architecture Using TiO2-Coated Vertically Aligned Carbon Nanofiber Arrays. ACS Applied Materials & Interfaces 2009, 1, (8), 1645-1649.

Liu, J.; Essner, J.; Li, J., Hybrid Supercapacitor Based on Coaxially Coated Manganese Oxide on Vertically Aligned Carbon Nanofiber Arrays. Chem. Mater. 2010, 22, (17), 5022-5030.

Other funding developed through the EPSCoR projects: “Coaxially Coated Vertical Carbon Nanofiber Arrays as 3D Multifunctional

Electrodes for Battery-Supercapacitor Hybrids”, National Science Foundation, $280k, 06/01/2011 – 05/31/2014

Additional significant activities/results/notes: Co-organized and co-chaired (with F. D’Souza and J. Wu) the Symposium on

“Energy: Materials and Devices” at 45th ACS Midwest Regional Meeting, Oct. 28th, 2010, Wichita, KS.

Supervised one REU student through NSF funded program on “REU Site: Earth, Wind, and Fire: Sustainable Energy for the 21st Century” (PI: Keith Hohn and Larry Ericsson)

Manipulating photons and electronics at nanoscale for high efficiency thin film solar cells

Objective: To understand the photoconductivity in

TiO2/CNF DSSCs To develop schemes for manipulating photons

and electrons at nanoscale

Link with other EPSCoR projects: Theme I: broadband dye (Francis D’Souza,

Victor Chikan) Theme II: Nanostructured materials and

characterization (Jun Li, Ron Hui, Cindy Berrie, Hui Zhao)

What have been accomplished: Study of conductivity and photoconductivity in single CNF/TiO2 core-shell nanowires Crystallinity of TiO2 shell found critical Schemes established in photonic and plasmonic PVs

What to be done: Optimizing photonic and plasmonic structures Exploring hybrid energy device ideas

People involved: PI: Judy Wu (KU) Participant: Caitlin Rochford, Zhuangzhi Li, Guowei Xu, Gary Melek, Fengli Wang, Jianwei Liu, Logan Wille, Collaborators: Cindy Berrie, Tina Edwards; Ron Hui, Chan Wang, Hui Zhao, Brian Ruczika, Teresa MacDonald, Alice Bean (KU); Jun Li (KSU), Francis D’Souza, Navaneetha Krishnan (WSU)

CNT/TiO2–DSSC (Jun Li)

hν COOH

COOH Approach

-

+ Pt

Graphene nanohole arrays provide a unique scheme to improve both light transmittance and electrical conductance

Single nanowire approach to probe photon and electron behavior at nanoscale

Publications: C. Rochford, Z.Z. Li, J. Baca, J.W. Liu, J. Li and J. Wu, “The effect of crystallinity on the

photoconductivity of CNF-TiO2-dye core-shell nanowires”, Applied Physics Letters 97, 043102 (2010).

Z.Z. Li, C. Rochford, J. Baca, J.W. Liu, J. Li, and J.Z. Wu, “Investigation of photoconductivity in single CNF/TiO2-dye core-shell nanowire devices”, Nanoscale Research Letters (2010) DOI 10.1007/s11671-010-9665-3.

Jianwei Liu, Judy Wu, Tina Edwards, Cindy Berrie, David Moore, Javier Baca, Zhijun Chen, Victor A. Maroni, M. Parans Paranthaman, Amit Goyal, “Triangle single crystalline graphene nucleation on rolling assisted biaxially textured copper substrates”, submitted (April 2011).

Jianwei Liu, Guowei Xu, Caitlin Rochford, Rongtao Lu, Zhijun Chen, Victor A. Maroni, Tina Edwards, Cindy Berrie, and Judy Wu, “Graphene photonic crystal for broadband flexible transparent conductors”, submitted (Mar 2011)

Other funding developed through the EPSCoR projects: Judy Wu (PI), Co-PIs: Cindy Berrie, Susan Williams, Val Smith and Lucas Miller, “An

Interdisciplinary Scholarship Program for Undergraduates in Renewable Energy SSTEM Scholarship”, NSF, $552,098 (Recommendation for funding, waiting for official notice), 07/01/2011-06/30/2014

Judy Wu (PI), co-PIs: Teresa MacDanald and Alice Bean, “Adventures at Nanoscale: Superconductivity”, NSF, $149,999, 10/01/2011 – 09/30/2013, (Recommendation for funding, waiting for official notice)

Judy Wu (PI): Probing and manipulating conductivity/superconductivity in nanostructures, NSF, $503,762, 06/01/11 – 05/31/15

Additional significant activities/results/notes: Co-organized and co-chaired (with F. D’Souza and J. Wu) the Symposium on “Energy:

Materials and Devices” at 45th ACS Midwest Regional Meeting, Oct. 28th, 2010, Wichita, KS.

Photocatalytic Water Splitting: Hydrogen and Oxygen Production Using Visible Light Frequencies

Objective: Develop improved catalysts to generate H2 as

“Solar Gasoline” and O2 from pure water. Employ mechanism of overall water splitting using

the Z-scheme photocatalysis system driven by electron transfer in photocatalysts

Approach

Link with other EPSCoR projects: Theme II: Materials and fundamental

processes of photoelectrochemical cells (Judy Wu, Jun Li) and photocatalytic reduction of CO (Paul Rillema)

Theme I: broadband dye (Francis D’Souza)

People involved: PI: Kenneth Klabunde Participant: YenTing Kuo, Dr. Caihong Chen

What have been accomplished: TiO2/In2O3 oxy(nitride) photocatalytic hydrogen production

under UV-Vis light. Lanthanum titanate photocatalytic water splitting under

UV-Vis light. Strontium titanate photocatalytic hydrogen production

under visible light. Bismuth vanadate oxygen production under visible light.

Strontium titanate

Bismuth vanadate

Fe3+/Fe2+

Z-scheme photocatalysis

system

R

R

Development of Solar Sensitizer Dyes for DSSC and Catalytic Reduction of CO2 into Higher Energy Products

Objective: To develop a series of Re(I) and Re(II)

catalysts for CO2 adduction through photocatalysis

To use these catalysts in DSSCs To Extend such materials for electrical energy

storage

Approach

Link with other EPSCoR projects: Theme II: nanowire device study (Jun Li &

Judy Wu) Theme I: broadband dye for DSSCs (Francis

D’Souza),

People involved: PI: Paul Rillema Participant:

Venu KomReddy, Eric Oweggi

What have been accomplished: Synthesis of a series of Re(I) and Re(II) catalysts Optical spectroscopy and time-resolved photoluminescence measurements accomplished a photoelectrochemical cell has been designed.

What to be done: Attachment of the Rhenium dye to TiO2 making it a photocathode, and replacing the sacrificial reagent (TEOA) with a photoanode in a photoelectrochemical cell which would produce both electricity and carry out a catalytic reaction at the same time

Re(I) series

Experimental Setup

Re(II) series R = H CH3 COOH COOCH3 COOC2H5

Reaction Mechanism