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IRG4: Nanomaterials for Renewable Energy

IRG4 Leader

Gerardo Morellgerardo.morell@upr.edu

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

IRG 4 Research Focus (revised in response to 2015 RSV)

The Interdisciplinary Research Group 4 aims to develop next-

generation photovoltaic devices based on nanostructured

ferroelectric semiconductors, taking advantage of the spontaneous

electric polarization of these materials for the separation of the

nascent electron-hole pairs as light is absorbed. To this end, IRG4

implements a comprehensive research agenda that integrates the

following key components:

(a) Synthesis and characterization of ferroelectric semiconductors

with narrow band gap in the visible region,

(b) Theoretical modeling studies to guide the experimental research

and provide fundamental understanding, and

(c) Fabrication and testing of prototype photovoltaic devices

based on narrow bandgap ferroelectric semiconductors.

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

IRG4 Senior Personnel

1. Zhongfang Chena,

2. Peter X. Fenga,

3. Luis F. Fonsecaa,

4. Pasquale Fulvioa,

5. Ram S. Katiyara,

6. Junqiang Lub,

7. Vladimir Makarova,

8. Carlos Marinb,

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

aUPR Rio PiedrasbUPR MayaguezcUPR HumacaodMetropolitan UniversityePolytechnic University

9. Gerardo Morella,

10.Ratnakar Palaia,

11.Luis Rosac,

12.Sushma Santapurie,

13.Mitkel Santiagod,

14.Maharaj Tomarb,

15.Josee Vedrinec,

16.Julian Veleva,

Strategic Partners: Dr. James F. Scott, St. Andrews University;

Dr. Evgeny Tsymbal, Dr. Peter Dowben, Dr. Alex Sinitskii and Dr. Barry Cheung,

University of Nebraska at Lincoln; Dr. Andrew Rappe, UPenn;

Dr. Wojciech M. Jadwisienczak, Ohio University

IRG4 Participants

Postdoctoral Fellows:

Dr. James S. Young, Dr. Muhammad Sajjad, Dr. Rajesh Katiyar

Graduate Fellows: Shalini Kumari, Yunlong Liao, Javier Palomino,

Radhe Agarwal, Tej Limbu, Omar Vega, Jose Hernandez, Daysi Diaz

Graduate Research Assistants: Bibek Thapa

Undergraduate Research Assistants: Jabril Vilmenay, Ernesto Espada

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Ferroelectric Photovoltaics

Schematic illustration of ferroelectric photovoltaic effect

Crystal polarity creates

microscopic electric fields across

the domains as depicted in figure

Responsible for separation of

photo-generated excitons into free

charges

Transport of free charges to

contact with minimum

recombination rate

Ferroelectric materials can achieve high open circuit voltages (Voc), unlike a p-n junction

photovoltaic cell where Voc is constrained by optical band gap of absorber material.

FE-PV vs p-n junctions

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Limitations:

• High band gap > 2.7 eV

• Low short circuit current ~ nA/cm2

• Low conversion efficiency less than ~ 0.01%

Opportunities:

• No conventional p-n junction required

• Open Circuit Voltage not limited by the material band gap

• No degradation of device performance in the 273 100 K range

• Abundant precursor materials

Ferroelectric Photovoltaics

Strategies:

• Band gap can be lowered to ~ 2 eV by doping and substitutions

• Control of defects to obtain photocurrents in the ~ mA/cm2 range

Enhanced Photoresponse in

BiFeO3/SrRuO3 Heterostructures

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Journal of Alloys and Compounds 609, 168, 2014.

short circuit current density ~63µA/cm2

open circuit voltage of ~0.08 V

rhombohedra R3c space group

7

Effect of Poling on the Photovoltaic Properties of

Highly Oriented BiFeO3/SrTiO3Thin Films

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Integrated Ferroelectrics, 157:168–173, 2014 8

Switchable Photovoltaic Effect in Bilayer

Graphene/BiFeO3/Pt Heterostructures

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Applied Physics Letters 105, 142902, 2014.

PFM images

9

Ferroelectric Photovoltaic Effects in

Doubly Substituted BLFTO Thin Films

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Current density as a function of

applied bias voltage for the

Pt/BLFTO/ZnO:Al heterostructures

Applied Physics Letters 106, 082903, 2015.

[Bi0.9La0.1][Fe0.97Ta0.03]O3 (BLFTO)

ISC ~1.35 mA/cm2

VOC ~0.20V

Si-modified BiFeO3 Ferroelectric PV

for Light Harvesting Windows

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Applied Physics Letters 107, 062902 , 2015.

[BiFe0.95Si0.05O3] (BFSiO)

Graphene

ISC 0.75 mA

VOC 0.45 V

ITO

ISC 0.63mA

VOC 0.35V

Band Gap ~ 2.2

Power conversion

efficiencies:

A: 3.64%

B: 1.96%,

Graphene Transparent Electrodes

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

DRM 51, 34, 2015; AIP 6, 35319, 2016

HFCVD Bilayer Graphene

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Limitations:

• High band gap > 2.7 eV

• Low short circuit current ~ nA/cm2

• Low conversion efficiency less than ~ 0.01%

Ferroelectric Photovoltaics

Accomplishments:• Band gap ~ 2.2 eV

• Short circuit current ~ mA/cm2

• Conversion efficiency less than ~ 3%

Opportunities:

• No conventional p-n junction required

• Open Circuit Voltage not limited by the material band gap

• No degradation of device performance in the 273 100 K range

• Abundant precursor materials

IRG4: Peer-Reviewed Publications

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

1. ACS Applied Materials and Interfaces 6, 13815, 2014.

2. Angewandte Chemie International Edition 54, 3112-3115, 2015.

3. Applied Physics Letters 105, 072908, 2014.

4. Applied Physics Letters 105, 142902, 2014.

5. Applied Physics Letters, 105, 172904, 2014.

6. Applied Physics Letters 106, 082903, 2015.

7. Carbon 75, 113, 2014.

8. J. Physical Chemistry C 118, 25051–25056, 2014.

9. Diamond and Related Materials 51, 34, 2015.

10. Electrochimica Acta 147, 392-400, 2014.

11. Integrated Ferroelectrics 157, 168, 2014.

12. ISRN Electrochemistry, 359019, 2014.

13. Journal of Alloys and Compounds 641, 99-105, 2015.

14. Journal of Alloys and Compounds, 609, 168-172, 2014.

15. Journal of Applied Physics 115, 84102, 2014.

16. Journal of Nano Energy and Power Research 3, 1-4, 2015.

17. Journal of Nanotechnology, 381273, 2014.

18. Phys. Chem. Chem. Phys., 17, 2160-2168, 2015.

19. Physica Status Solidi C 12, 413-417, 2015.

20. Royal Society of Chemistry Advances 5, 11240-11247, 2015.

Density Functional Theory of Bi1-xKxFeO3

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Spin_down

Spin_up

K doping produces a significant reduction in bandgap and leakage current

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

• We encourage the focus on the basic research on

ferroelectric materials for energy harvesting. It is a field

where this group can make significant impact since

few other groups work in this area.

• We would encourage this team to develop the basic

understanding of the physics of carrier transport in

these ferroelectric materials and the dependence of

built‐in fields, domain size, interface and contacts.

• The fundamental understanding of these effects would

significantly enhance the value of this research.

2016 EAB Comments on IRG4

EPSCRoRESEARCH IN PUERTO RICO

EPSCRoRESEARCH IN PUERTO RICO

Institute for Functional NanomaterialsUniversity of Puerto Rico http://www.ifn.upr.edu

Thank you for your attention

IRG 4: Nanomaterials for Renewable Energy