School of Photovoltaic and Renewable Energy Engineering

Photovoltaics Education and Research at UNSW and

ACAP/AUSIAPV

R. Corkish, COO, Australian Centre for Advanced Photovoltaics r.corkish@unsw.edu.au www.pv.unsw.edu.au

www.acap.net.au

UNSW at a Glance Member Universitas 21, Group of Eight

Specific scientific and technological focus

Large and highly regarded Engineering and Business faculties

Defined internationally recognised research strengths focusing on contemporary and social issues in professional and scientific fields • Applied research and strong industry connections

Cosmopolitan and International: • Australian students from diverse backgrounds, many first in family

to university • 1st Australian University enrolling International Students (since

1951), now from > 120 countries; 20-25% International • #52 QS Rankings (5 Stars); • #132 ARWU Rankings (2013) • #69 Times Higher Education Rankings (2013) • #81-90 Times Higher Education global reputation rankings (2013) • #2 in Australia National Taiwan University Rankings

Faculty of Engineering • ARWU ranking: 56 for Engineering (1 in Australia) • National Taiwan University Ranking: 60 for Engineering (2 in Australia) • QS world ranking (2014): 33 in Engineering and Technology

– 33 in EE; 37 in Mech; 18 in Civ; 49 in Chem; 29 in CompSci • Budget approx. $282m (2014) • 691 staff in 2014, including

– 429 academic staff – 262 professional and technical staff

• 10,715 students in 2014, including – 5,278 local & 2,141 international undergraduate – 1,128 local & 1,234 international postgraduate coursework – 449 local and 485 international research

• 9 Schools http://www.engineering.unsw.edu.au/sites/eng/files/u7/PDFs/140403%20Faculty%20Profile%20-For%20webb.pdf

Irradiation (kWh/kWp)

Context: The exemplary path until 2050/ 2100

Reference: "World in Transition: Turning Energy Systems Towards Sustainability (Summary for Policy Makers)," German Advisory Council on Global Change, Berlin 2003. www.wbgu.de

Context: Photovoltaics Growth

By region of manufacture (Source: Photon Int.; GTM Research)

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2014 growth forecast (Source:

Solarbuzz 2013)

2010-2014 country shares

(Source: Solarbuzz

June 2014)

Australian module and system prices

(courtesy of M. Watt, Australian Photovoltaics Association)

Average Cell Efficiency (6” cells)

Bernstein Research, 4 April 2014

School History • PV research within UNSW

Electrical Eng. 1974 – 1998 • Separate Centre 1999 – 2005 • Pioneering UG photovoltaics

engineering program 2000 • PG coursework program 2001 • Second UG program 2003 • New School declared 2006

Undergraduate Education Two 4-year Engineering programs (420 students): • Photovoltaics and Solar Energy (started 2000) • Renewable Energy (started 2003)

(Session 1, 2014 figures)

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100150200250300350400450500

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Photovoltaics and Solar Energy First such specialist degree globally

– Technology development – Manufacturing – Systems engineering – Maintenance – Reliability and lifecycle

analysis – Marketing – Policy

Renewable Energy Eng. • Begun 2003 • Development shared with Murdoch Univ., Perth

– Photovoltaics – Energy Efficiency – Solar thermal – Wind – Biomass – Solar architecture

Postgraduate Education

• PG Coursework (49 students)

– Rapid growth 2007-10 – Strong AUD in 2011, 2012 – 1.5 year addition to 4-year

BEng. or 4-year BSc

• Research degrees – PhD (93 students), – Masters Research (10 students) – Historically through Electrical

Eng. (S1, 2014 figures)

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Tyree Energy Technologies Building

• Home to interacting energy research activities – Australian Energy Research Institute – School of Photovoltaic & Renewable Energy

Engineering – ARC Photovoltaics Centre of Excellence – Cooperative Research Centre for Low Carbon Living – Centre for Energy and Environmental Markets – ARC Centre for Functional Nanomaterials – Vanadium Battery Research Group of School of

Chemical Science and Engineering – School of Petroleum Engineering

• 6 Star GreenStar energy efficient building – 140kWpeak rooftop PV array of Suntech “Pluto”

selective emitter solar photovoltaic modules – Gas-fired tri-generation – Solar access control – Labyrinth precooling of intake air – Living laboratory

Australia-US Institute for Advanced PV Funded through the Australian Renewable Energy Agency

• UNSW •Australian National University • University of Melbourne • Monash University • University of Queensland • CSIRO • NSF-DOE QESST (Arizona State Univ.) • U.S. National Renewable Energy Laboratory (NREL) • Sandia National Laboratories (U.S.) • Molecular Foundry (U.S.) • Stanford University • Georgia Institute of Technology • University of California - Santa Barbara • Suntech R&D Australia • BT Imaging • Trina Solar Energy • BlueScope Steel

• PP1: Silicon Cells • PP2: Organic and Earth-Abundant Inorganic Thin-Film Cells • PP3: Optics & Characterisation • PP4: Manufacturing Issues • PP5: Education, Training and Outreach

2013 Annual Report: http://www.acap.net.au/annual-reports

Program

PP1 Silicon Cells – Lead Institutions: UNSW/ANU

PP2 Thin-Film, Third Generation & Hybrid Devices – Lead Institutions: UNSW/Melbourne /Monash/Qld/CSIRO

PP3 Optics and Characterisation – Lead Institution: Univ Qld/UNSW/ANU

PP4 Manufacturing Issues – Lead Institutions: UNSW/CSIRO

PP5 Education, Training and Outreach – Lead Institutions: UNSW/ANU/Melbourne/Monash/Qld/CSIRO

Annual Report 2013: www.acap.net.au/annual-reports

www.acap.net.au/research

AUSIAPV and ACAP

PV Factory – entrance page

PV Factory

PVL, UNSW & ASU are creating a virtual PV factory – Simulates a solar cell production line. – Founded on UNSW’s Virtual Production Line software. – Integrated with PVL’s alorgithms for solar cell physics. – 12-month project funded by PVL, UNSW & ACAP. – Aug 2014: Beta testing during UNSW manufacturing course. – Jan 2015: Freely available online.

ASU’s Advanced Manufacturing

Already delivered at ASU in 2013 – Adj. Prof. Jeff Cotter – 38.5 hours – Over 7 weeks – 20 undergarduates – 4 postgraduates – ~2400 VPL batches

Already delivered at ANU in 2013 – Adj. Prof. Jeff Cotter – 14 students

Propose ACAP support attendance at ANU, UNSW – Out-of-town staff and students of ACAP partners – Offer to research/educational and industrial partners – Share of fees, where applicable – Share of domestic travel, where applicable – Share of accommodation for short-course deliveries or equivalent,

where applicab – Remainder funded by home node or student

Images courtesy of Jeff Cotter, (ASU)

Generations of Photovoltaics

First Generation: Wafers/Ribbons

25% Efficient PERL Cell 17% Industrial Screen Printed Cell

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UNSW

Selective Emitter – 3 Technologies • Semiconductor Fingers:

– Diffusion doped lines replace doped grooves

– Screen-printed metal fingers run perpendicular to diffused lines

• Laser Doped Selective Emitter – Laser doping through/from dielectric

layer – Dielectric doubles as ARC and plating

mask – Laser doping gives heavily doped

surface ideal for self aligned plating and selective emitter

• Transparent Fingers – Semiconductor Fingers with laser doped

lines – Laser doped lines replace doped

grooves

Dopant

Green laser selectively removes ARC dielectric and melts the silicon underneath

Molten Si freezing simultaneously incorporates heavy n-type Phosphorus doping

High temperature at localised regions only

Self aligned base metal plating into laser pattern – - low cost materials, - in line process flow, - fast LIP plating, - zero contact

Performance > 19% LDSE, > 20% D-LDSE

Chemistry aspects: Plating Cu/Nu

Adhesion to Si

Avoiding Cu – Si contact

Laser Doped Selective Emitter

dielectric

p-type

N+ N++

Green Laser

• ~$10 million project (40% ARENA funding) • Multiple partners (cell and tool manufacturers, special materials) • 5 years (started in 2014) • 5-10 academic staff • Developing “lean” technologies to reduce recombination in silicon

– Improve existing screen print cells – Enable high efficiency cell architectures – Enable low cost substrates

• New PECVD recipes • Defect passivation processes • Studying impact and control of thermal cycles

Hydrogenation research at UNSW

Advanced Hydrogenation on UMG Material

Lifetime: <1 microsec several microsec >400 microsec

No Hydrogenation Standard Hydrogenation UNSW tricks

Carrier Selective Contacts

GaAsP on SiGe Tandem

UMG Si cells at ANU

ANU 24.4% REAR JUNCTION CELL

Second Generation (Thin Films)

‘Crater’

‘Dimple’ Glass

‘Groove’

p+ p n+

Metal

Si Insulator

Light

‘Crater’ ‘Dimple’

‘Moses’

Cell n Cell n+1

Image: CSG Solar

• Thin films on supporting substrate – Amorphous/microcrystalline Si – CIGS (In: CRITICAL (US DoE)) – CdTe (Te: NEAR-CRITICAL (US DoE)) – Crystalline Si on glass or conductive carrier – Organic PV – Cu2ZnSnS4 (CZTS) – Perovskite

• Lower efficiency than wafers but lower cost per m2

• Large manufacturing unit • Fully integrated modules • Aesthetics

Plasmonic Evaporated Cells Surface plasmon enhanced light-trapping (planar glass)

Si QD

metal nanoparticles

Second Generation (Thin Films) - Organic • Potentially low cost, but:

– Low efficiency – Poor stability – High cost of current materials

• Ab-initio modelling of new polymer materials

• Morphology control of bulk heterojunction organic solar cells

• Light trapping in organic solar cells Improved light trapping

• Organic/inorganic nanoparticles hybrid cells

• Organic-perovskite tandem cells

Aluminium Lithium fluoride

Donor/Acceptor Indium Tin Oxide Glass

CZTS thin films • Earth-abundant

• Low toxicity

• IBM demonstrated 9.7% in 2009

• Hydrazine-based solution deposition

• Physical vapour deposition

• Reactive sputtering

Silicon-based Tandem Cell

GaAsP – Si/Ge Tandem Cell • UNSW, AmberWave Inc., Veeco Inc., Yale University,

University of Delaware, Arizona State University, National Renewable Energy Laboratory, Australian NanoFabrication Facility.

• Si substrate • Si/Ge alloy bottom cell to convert long wavelength light • GAsP top cell to convert short wavelength light

III-V – Si Tandem Cell on Virtual Ge Substrate • UNSW and the National Renewable Energy Laboratory. • Low cost Si substrate • Thin layer of crystalline Ge to be grown on a Si wafer by

economic physical vapour deposition – “virtual Ge wafer” • GaInP/GaInAs top cells to convert short wavelength light

CZTS (Cu2ZnSnS4) – Si Tandem Cell • Abundant elements • Non-toxic element • Rapid improvement in efficiency

Perovskite – Si Tandem Cell

Si

Organic–Inorganic Halide Perovskites • Refer seminar 10 July Prof. Martin Green

http://www.engineering.unsw.edu.au/energy-engineering/public-research-seminars

• Rapid efficiency improvement • Inadequate stability (moisture, UV) • Pb content (ROHS) • Opportunity for lower processing cost or higher efficiency? • Capitalize on >20 years development of dye-sensitized

and organic PV • ABX3, where X = anion, A & B = cations (A being larger

than B) • Main interest:

– A is organic (CH3NH3+) or (CH3CH2NH3

+) or formamidinium (NH2CH=NH2

+) – B is Pb or Sn – X is halide: I or Br or Cl – CH3NH3PbI3 or mixed halides, CH3NH3PbI3−xClx and

CH3NH3PbI3−xBrx

Efficiency Loss Mechanisms

Two major losses – 50%

Limiting efficiencies 1 sun Single p-n junction: 31% Multiple threshold: 68.2%

qV

2. Lattice thermalisation

2

2

1. Sub bandgap losses Energy 3

Also: 3. Junction loss

4

4 4. Contact loss

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5

5. Recombination

1

Limiting efficiencies Max. Concentration Single p-n junction: 41% Multiple threshold: 86.8%

Silicon based Tandem Cell

Thin film Si cell Eg = 1.1eV

2nm QD, Eg =1.7eV

Si QDs

defect or tunnel

junction

SiO2 barriers

Engineer a wider band gap – Si QDs

SiC SiO2 Si3N4

Substrate Substrate

Annealing

Si1-xCx SiOx SiNx

Silicon based Tandem Cell

Si72(OH)64, dQD = 14 Å

Quartz substrate

P doped bilayers

B doped bilayers

Al contacts

B doped bilayers

B doped bilayers

SRO 4nm

SiO2, 2nm

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Vapplied (V)

I (nA

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492mV

Hot Carrier Cell Extract hot carriers before they can thermalise: 1. need to slow carrier cooling 2. need energy selective, thermally insulating contacts

Spectrum Splitting for Concentrating PV

Photoluminescence Imaging

Images courtesy of BT Imaging

SPREE Research Topics (not PV devices) • Cooperative Research Centre for Low Carbon Living

(www.lowcarbonlivingcrc.com.au)

• Led by UNSW Faculty of Built Environment & SPREE

• Modular building energy efficiency (with Novadeko)

• Energy end-use efficiency

• PV and thermal and buildings

• PV modules and encapsulation

• Wind/solar resource forecasting and synergies

• PV opportunity mapping

• Energy policy

• Combustion modelling

• Solar thermal technologies

आपका ध्ाा के �लए धन्याा!

“This Program has been supported by the Australian Government through the Australian Renewable Energy Agency (ARENA). The views expressed herein are not necessarily the views of the Australian Government.”