school of photovoltaic and renewable energy engineering...
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School of Photovoltaic and Renewable Energy Engineering
Photovoltaics Education and Research at UNSW and
ACAP/AUSIAPV
R. Corkish, COO, Australian Centre for Advanced Photovoltaics [email protected] 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
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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40000MWp
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Japan
Europe
Rest ofWorld
2014 growth forecast (Source:
Solarbuzz 2013)
2010-2014 country shares
(Source: Solarbuzz
June 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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l No.
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stu
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Year
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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2002 2004 2006 2008 2010 2012 2014 2016
No.
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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
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)
First Generation: Wafers/Ribbons
25% Efficient PERL Cell 17% Industrial Screen Printed Cell
0
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Effic
ienc
y, %
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
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
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
5
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
V +
-
-100
0
100
200
300
400
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600
700
800
-1.5 -1 -0.5 0 0.5 1 1.5
Vapplied (V)
I (nA
)
-500
-400
-300
-200
-100
0
100
0 0.1 0.2 0.3 0.4 0.5 0.6
Vapplied (V)
I (nA
)
492mV
Hot Carrier Cell Extract hot carriers before they can thermalise: 1. need to slow carrier cooling 2. need energy selective, thermally insulating contacts
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