“Resources, Energy, Environment, Social Infrastructure” Field
Achievement : developing high-efficiency silicon photovoltaic
devicesAchievement : developing high-efficiency silicon photovoltaic

devicesProf. Martin Andrew
Green (Australia)

72)
Born: July
20,Martin
1948 (Age:Prof.
Andrew
Green (Australia)
Professor,of New(Age:South72) Wales (UNSW Sydney)
Born:University
July 20, 1948

Professor, University of New South Wales (UNSW Sydney)

Predicted Growth of Solar Power

Predicted Growth of Solar PowerThe mechanisms behind solar photovoltaic devices
and solar power generation

The mechanisms behind solar photovoltaic devices
and solar power generation

There are many types of devices that generate power from sunlight,
but crystalline silicon (a type of semiconductor) is said to be found in
approximately
95% ofofphotovoltaic
devices
in usepoweraroundfrom
the world.
The
There
are many types
devices thatgenerate
sunlight,

but crystalline
silicon(a typeof bysemiconductor)
saidScenario,
to be foundinInstalled power
generation
capacitysource in the State is
Policies
2000-2040
approximately
95% of photovoltaic devices in use around the world. The
GW (Gigawatts)
3500

Coal

Installed power generation capacity by source in the State Policies
Scenario,
2000-2040
Natural Gas
Solar PV
3000

GW (Gigawatts)
3500
2500

3000
2500

2000
1500

2000

1000

1500

500

1000

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Coal

Natural Gas

Hydro

Coal

Solar PV

Wind

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Nuclear Hydro

0
2000

2005

2010

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2015

2020

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2025

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NuclearCoal
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Natural Gas
Solar PV
Oil
Other
Nuclearrenewables
Wind
Hydro
Solar
PV storage
Battery[Inﬂation adjusted Euros (2019)/Wp]
Module Price

PERC solar cells and Prof. Green’s role
improvingsolar
efficiency
ininimproving
solar
cellcellefficiency

Thefirst
first
efficientp-n-junction
crystalline
solar
was demonTheefficientp-n-junction
crystalline
siliconsiliconsolar cellwascelldemonstratedbyby
Daryl.
Chapin,CalvinS. Fuller,
and Gerald
L. Pearson
stratedDaryl.
M. M.
Chapin,CalvinS. Fuller,
and Gerald
L. Pearson
at Bell at Bell
Labs
From
1972
to 1974,
JosephLindmayer,
James F.
Allison,Labsinin1954.
1954.
From
1972
to 1974,
JosephLindmayer,
James
F. Allison,
Josephandandcolleagues
at COMSAT
Laboratories
improved
JosephG.G.Haynos
Haynoscolleagues
at COMSAT
Laboratories
improved
power
efficiency
to nearly
17%.17%.
However,
there were
nowerefurther
powerconversion
conversion
efficiency
to nearly
However,there
no further
improvements
in power
conversion
efficiency
for nearlya decade.
improvements
in power
conversion
efficiency
for nearlya decade.
In 1975, Prof. Green then provided fresh insight into the processes determinIn 1975, Prof. Green then provided fresh insight into the processes determining the recombination of electrons and holes excited by sunlight and suggested
ing therecombinationelectrons
by sunlightandInsuggestedmuchhigherconversion ofefficiency
of and25%holeswas excited
experimentallyfeasible.
muchhehigherof 25% ofwasexperimentallyfeasible. In
1983,
and hisconversion
team realizedefficiency
a record efficiency
18%.
This was the firsthe andteam realizedof achieving
18%. This24.7%
was the firstin1983,a seriesof 18hiscertified
efficiencya record
records efficiency
by his team,in a seriesof 18
certifiedrecordsby his team,achieving 24.7%
efficiency
in 1999(reaching
his efficiency
target of 25.0%
by recalibrationin 2008).
The PERCincell
that(reaching
he invented
not only reducing
efficiency
1999
hisincluded
target ofmeasures
25.0% byforrecalibrationin 2008).
recombination
the hetopinvented
region ofincluded
the cell measures(the “emitter”)
butonly
alsoreducing
The PERCalongcell thatfor notalong
the rear of thecell asPERC
thebut also
recombination
along
thewell.
topThisregionof structure
the cell now(thedominates“emitter”)
photovoltaic
devicemarket.
along the rearof thecell as well. This PERC structure now dominates thephotovoltaic device market.

Building a more secure society with solar power generation

Building a more secure society with solar power generation

than fossil fuel power. This change is encouraging companies to enter thesustainable energy market and is driving a policy push for renewable energy,

2010

2015

2020

2025

2030

2035

2040年

Source: IEA World Energy Outlook 2019
1990

1980

10
Price reduction
and spread of solar photovoltaic devices

100

2010

2000
1

2015

1990

1980

0.0
0.001

0.01

History

1954

1973

1975

1983

1983

2008

Oxide

n-emitter

Local diﬀn(publisheProf. Gre
the main
Green.

2040年

Nuclearwhich ibonizedto the cof newbackgrwho desolutioneurs wSola
dioxidemore ecells. M
from laresidengenerascale oother rinfrastmore s1999

The decades-old notion, that renewable energy is important for global
environmental protection but is too expensive, has completely changed, as
the society-wide
adoptionof photovoltaics
has madesolaris power
cheaper
The decades-old
notion,that renewableenergyimportantfor global
thanfossil fuel power.
This change
to enter changed,
theenvironmental
protection
but is is
tooencouraging
expensive,companies
has completelyassustainableenergy market
and isofdrivinga policy pushrenewable
the society-wide
adoption
photovoltaics
has formadesolar energy,
power cheaper

Otherrenewables
Hydro
Battery storage

Price reduction and spread of solar photovoltaic
devices
Battery storage Oil02000 1002005

1

when the electrons and holes recombine. (see below figure.)

1km

Source: IEA World Energy Outlook 2019

500

10

majority of those are p-n junction solar cells, which have p-type siliconis placed adjacent to n-type silicon. When struck by photons from the
majority of those are p-n junction solar cells, which have p-type siliconsun, the energy causes the release of a negatively-charged electron andis placed adjacent to n-type silicon. When struck by photons from thea positively-charged “hole,” whereby the electron moves into the n-typesun, the energy causes the release of a negatively-charged electron andand the hole“hole,”
moveswhereby
into thethep-typesilicon.
then flows
asiliconpositively-charged
electronmovesThat
into charge
the n-type
out theandelectrodes(or contacts)
as electricalsiliconthe hole moves
into the p-typesilicon.power.
That charge then flows
A highpower(orconversion
efficiency
be obtained if every electron-holeout theelectrodes
contacts) as
electricalcan
power.
pair
thatpower
is generated
canefficiency
be extracted
as obtained
power, but
in practice,energy is lostA highconversion
can beif everyelectron-holepairthattheis generated
extracted
as power,(seebut inpractice,energy is lostwhenelectronscan
andbeholes
recombine.
below
figure.)PERC solar cells and Prof. Green’s role

In orderto realize
our dreamsof achieving
In orderto realize
our dreamsof achievinga adecarbonizeddecarbonized society,society,
there needs
to be toa shifttowards
the theuseuseof ofelectricalby
there needs
be a shift
towards
electricalpower
powergenerated
generated byrenewable
sourcesthat docarbondioxide,a contributing
torenewable
sources
thatnot
do emitnot emit
carbondioxide,a contributing factor
factor to
global global
warming.
Renewables
includesolar,
wind,
warming.
Renewables
includesolar,
wind,andandgeothermal
geothermal power,
power,
but past,in the introducing
past, introducing
sourcesdifficultdue
duetotothe
the increased
increased
but in thesuchsuchsources
waswasdifficultcosts comparedwhen compared
to fossil
fuel-fired
plantshydroelectric power.
power.
costs when
to fossil
fuel-fired
plantsandandhydroelectric
the mid-2010s,
power
droppedbelowthose
thoseofof fossil
fossil fuelIn the In
mid-2010s,
solar solar
power
costscosts
droppedbelow
fuelandbeganthus began
the oferasolarof solarpower
plantsbeing
beingable
able toto be
be built
built
power, power,
and thus
the erapower
plantscheaper than fossil fuel plants. Solar power generation is expected to undergo
cheaper than fossil fuel plants. Solar power generation is expected to undergo
rapid expansion in the future (see below graph). Behind this paradigm shift is
rapid expansion
the future (seebelowgraph). Behindparadigm
shift isthe ability inof photovoltaic
devices(commonly
known asthis
solar
cells) to convert
the ability
photovoltaic
devices
as solarto convert
solarofenergy
to electric
power (commonlyat high rates knownof efficiency,
andcells)
the reductioninsolar energy
electric power
at highof forefficiency,
and theofreductioninpower togeneration
costs thathave rates
allowedthe construction
large-scale
power generation
allowedforworking
the constructionof large-scalesolar power costs
plants.that
Prof.haveGreen
has been
on improving
conversion
efficiencyof crystalline
silicondevicessince the 1970s,
and hesolar power
plants.
Prof. Green
hasphotovoltaic
been working
on improving
conversion
has ofachieved
many silicon
successes
over that time.
efficiency
crystalline
photovoltaic
devices since the 1970s, and hehas achieved many successes over that time.

[Inﬂation adjusted Euros (2019)/Wp]
Module Price”“Resources, Energy, Environment, Social Infrastructure” Field

Source : Google Earth
Noor Abu Dhabi PV Power Plant, a gigawatt-level solar power plant in Abu Dhabi. This power plantis installed with the p-n junction crystalline silicon PERC cells invented by Prof. Green. PERC devices
1km
are considered environmentally friendly because they can generate between 10 and 30 times theamount of energy required to produce the devices, depending on location and technologies used.
Source : Google Earth(Source: Google Maps）

Noor Abu Dhabi PV Power Plant, a gigawatt-level solar power plant in Abu Dhabi. This power plantis installed with the p-n junction crystalline silicon PERC cells invented by Prof. Green. PERC devices
are considered environmentally friendly because they can generate between 10 and 30 times theElectronamount of energy required toHole
producethe devices, depending on location and technologies used.
(Source: Google Maps）

Mega-so

Front contact

0.1 2000

1

2010
10

N-type silicon
100

Cumulative production (GWp)

1000

10000

2015

Up until 2000, improvements in conversion eﬃciency were a major factor in the reduced cost of solar
photovoltaic devices, but in the 2000s, the increased size of power plants also began to contribute tolower prices. Prof. Green has contributed to both, having been involved in both technological
0.0development and the cultivation of individuals who are involved in the evolution and expansion ofsolar power
generation.
Report,0.001
0.01
0.1 (Source:1 Photovoltaics
10
100 Fraunhofer
1000 Institute10000 for Solar Energy Systems,
ISE with support of PSE
Projects GmbH,
16 September
Cumulative
production(GWp)2020)

Up until 2000, improvements in conversion eﬃciency were a major factor in the reduced cost of solar
photovoltaic devices, but in the 2000s, the increased size of power plants also began to contribute to

p-n junction

Front contact
N-type silicon

P-type silicon
Rear contact

p-n junction

HoleElectron

Recombination

Recombination

Recombination

Large anto matchplants c
redistribsiliconom theon andn-typeflows

n-holeis lostemonat Bellllison,provedfurthererminggested
ble. Inhe first
24.7%
8).
ducingut alsotes thenglobalged, asheaperter theenergy,“Resources, Energy, Environment, Social Infrastructure” Field
which in turn is accelerating the global movement towards a low-carbon/decar-

bonized economy.
Nowadays,high-efficiency
solar cells are recognizeda major solution
Achievement: developing
siliconasphotovoltaic
to the challenges
of sustainable energy and global warming, and various types
devicesof new solar cells are being actively researched and developed. Against thisProf.background,
MartintheAndrew
Green(Australia)
time has cometo recognize
the achievements of Prof. Green,

who developed
high-efficiency
silicon solar cell that has provided an actual72)
Born: July20, 1948a(Age:solutionto global issues,
along
the way
fostering
many engineers
Professor,
Universityof New
South
Wales
(UNSW
Sydney)and entrepre-

neurs who have transformed the industry.
Solar power is a clean energy source not only because it emits no carbon
dioxide when producing power, but also because solar power produces
more energy
than of
theSolarenergyPower
used to manufacture and dispose of solar
Predicted
Growthcells. Moreover, solar power can be flexibly adapted to meet various needs,
from large-scale megawatt and gigawatt level power plants to small-scale
In orderto realize
ourusing
dreamsof achieving
decarbonizedsociety,residential
generation
roof-top
solar arrays.aDistributed
electric
power
there needs
to bethrougha shift small-scale
towards thefacilities
use of canelectrical
powerthegeneratedbygeneration
help reduceseverity andrenewablethat caused
do not during
emit carbon
contributing
factorandtoscalesourcesof damagenaturaldioxide,
disasters.a Whensolar power
renewables
becomeinclude
the backbone
our electric
power generation
global otherwarming.
Renewables
solar, ofwind,and geothermal
power,
infrastructure,
we will such
have attained
to produce
in abut in thepast, introducing
sources thewasability
difficultdue to electricity
the increased
more comparedsustainable toway.
costs whenfossil fuel-fired plants and hydroelectric power.

In the mid-2010s, solar power costs dropped below those of fossil fuelof improvements
efficiency
power, History
and thus
began the era inofpower
solar generation
power plants
being able to be built
cheaper thanfossilfuelplants.
Solar
power
generationis
expected to undergo
1954
Bell Labs invents the ﬁrst eﬃcient crystalline silicon solar cell
rapid expansion in the future (see below graph). Behind this paradigm shift is
COMSAT Labs achieves 17% eﬃciency, an achievement thatthe ability1973
of photovoltaic
devices for(commonly
known as solar cells) to convert
remains unbroken
nearly a decadesolar energy to electric power at high rates of efficiency, and the reduction in1975 Prof. Green proposes new concept suggesting potential 1.5 times
power generation
costs thathave allowed
for therecombination
constructionof large-scale
increasein eﬃciency
using advanced
suppression
solar power plants. Prof. Green has been working on improving conversion
Prof. Green achieves 18% eﬃciency, which is achieved throughefficiency1983
of crystalline
silicon photovoltaic devices since the 1970s, and hepassivation of the silicon-electrode interface and current
has achieved manysuccesses
over thethatlocal
time.
extraction
throughtunnel junction
1983

Prof. Green invents PERC, which harnesses passivation on front
and rear surfaces

The mechanisms
behindsolar24.7%
photovoltaic
devices
1999
Prof. Green
achieveseﬃciency
and solar power generation
2008

Prof. Green’s solar cells certiﬁed at 25.0% eﬃciency

There are many types of devices thatgeneratePassivatedpower front
fromsunlight,
surface
Antireﬂection
for light trapping(published in 1984 paper)
but crystalline silicon (a Finger
typeelectrodeof semiconductor)
is said to be found in
approximately 95% of photovoltaic devices in use around the world. The
InstalledOxide
power generation capacity by source in the State Policies Scenario, 2000-2040
p+

GW (Gigawatts)
3500

n+

Coal
Natural Gas
Passivated rear surface
3000
Oil in 1985 paper)(published
Nuclear
Oxide
Local diﬀusion
2500
Wind
Natural Gas(published in 1999 paper)
Coal
Solar PV
2000Prof. Green’s high eﬃciency solar photovoltaic device (based on diagram in his 1999 paper) is now
Other
the mainstream device in the Si-PV market. The blue text denotes technologies developed by Prof.
renewables
1500Green.
Hydro
Hydro
Wind
Battery storage
1000

n-emitter

500

e Earther plant
devicesmes thees used.

0
2000

p+

p-type siliconp+p+Nuclear
2005

Smart grid

2010

2015

2020

2025

Small-scale hydroelectric
power
Battery storage Oil

2030

Professor, Johns Hopkins University School of Medicine

multiple onpresence ofDr. Robert A. Weinberg (USA)and greatly
Born: November 11, 1942 (Age: 78)
PERCWhiteheadsolar cells
and for
Prof.
Green’sResearchrole“tumor supMember,Institute
Biomedical
in improving
solarInstitute
cell efficiency
Professor,
Massachusettsof Technology (MIT)brakes. Th
cancer will
tumor supp
The
first
efficientp-n-junction
crystalline
silicon
solar
cell
was
demonSummary: Discoveries of oncogenes and tumor suppressor

stratedby andDaryl.
M. Chapin, Calvin S.ofFuller,
and Gerald L. Pearson at Bell
genes
proposal/verification
the multi-stepcarcinogenesis
model.
Labs
in 1954. From1972 to 1974, Joseph Lindmayer, James F. Allison,
Joseph G. Haynos and colleagues at COMSAT Laboratories improved
power
conversion
efficiency
to nearlyof17%.
However,
there
were no further Dr. Vog
Dr. Weinberg
discovered
the presence
cellulargenes, called
proto-oncoimprovements
inpower
conversion
efficiency
fornearlyadecade.
genes, which can be converted to cancer-causing oncogenes by a mutation(s).
1975,Prof. Greenprovided
intoa theprocesses
determin- Dr. Vog
HeInalso
contributedin thethen
discoveryof a fresh
gene, insightnow called
tumor
suppressor
genetics coing
thethatrecombination
ofthe
electrons
andofholes
by sunlightand Dr.
suggestedgene,
is required forprotection
cellsexcited
to becomecancer cells.
that a seriesmuchhigherconversion
efficiency
of
25%
was
experimentallyfeasible.
In
Vogelstein independently searched for actual mutated genes in human cancer
1983,
he discovered
and his teamrealizedrecordthat
efficiency
ofto18%.
This was the firstand others)
cells andnumerousnewa genes
are criticalthe developmentin
series On
of 18
efficiency
records theby concept
his team,achieving 24.7%increasinglyof acancer.
the certified
basis of theseachievements,of “multi-step
efficiency
in 1999(reaching
his target Althoughof 25.0% manyby recalibrationin 2008). of multi-ste
carcinogenesis
model”was established.
other investigators
The PERC
invented
includedmeasuresstandfor not
reducing
among thecontributed
to cellthis thatfield,heDrs.
Weinberg
and Vogelsteinoutonlyin thatrecombination
along
the topregionof pioneers
the celland(the“emitter”)
but also
as an onco
they continued theirinnovative
researchas theleaders
in corrobalongof theIncell
This PERC
structure
now dominatesthewith thoseoratingthe
thisrearconcept.
fact,asDr.well.
Weinberg
experimentallydemonstratedthephotovoltaic
devicemarket.
cancer geno
requirement of multiple oncogenes to convert normal cells into cancer cells,

oping mechwhile Dr. Vogelstein verified the concept by molecular genetics combined
basis of thewith histopathology of large intestinal lesions, from which human colorectal
cancers
arise, toshow theassociationof a withseries ofmutationsin cancer-assoBuilding
a moresecuresocietysolar
power
generation cornerstone
ciated genes. Thus, they revealed pivotal roles for certain human oncogenes
Figure 2:Funand tumor suppressor genes in the propagation and suppression of numerous
The decades-old notion, that renewable energy is important for global
DNA (RAS gene)common human cancers. Their discoveries have also led to the opening of theenvironmental
protection but is too expensive, has completely changed, as
fieldsociety-wideof cancer genomics,
nowof
an photovoltaics
especially powerfuldiscerning
andcheapertheadoptionhas forcemadeinsolar
power
developing
cancerdiagnostics andtherapeutics.
thanfossil mechanism-based
fuel power. Thishumanchangeis encouraging
companies
to enter thesustainable energy market and is driving a policy push for renewable energy,

Solar PV

Other renewables

Wind power

majority of those are p-n junction solar cells, which have p-type siliconis placed adjacent to n-type silicon. When struck by photons from theinto an inacsun,
the energy
causesMedicinal
the releaseScience”
of a negatively-charged
electron and“MedicalScience,field
the producta positively-charged “hole,” whereby the electron moves into the n-type
analogy to
Achievement
For movestheir pioneering
worksilicon.
in conceptualizing
a flows
siliconand the :holeinto the p-type
That charge thenThis “onmodelofmulti-stepcarcinogenesis
andits
application
andout the electrodes (or contacts) as electrical power.
impact on improving cancer diagnosis and therapeutics
Dr.
A high power conversion efficiency can be obtained if every electron-hole Weinb
which cannpair
thatBert
is generated
can be extracted
Prof.
Vogelstein(USA) as power, but in practice, energy is lostdemonstrat
Born: theJuneelectrons
2, 1949 (Age:71) recombine. (see below figure.)when
and holes

2035

2040年

Instruc

Dr. Weinberg’s achievements

Figure 3:Dn

Dr. Weinberg helped launch this new era of human cancer genes. In elegant
and original research, he introduced extracted and fragmented DNA fromcancer cells and then introduced the fragmented DNA into cancerous cells andfound an appearance of cancer cell clones (Fig. 1). When he then analyzed thecancer cell-derived genes in these cells, he discovered a mutated form of the
RAS gene. Normal RAS gene product is important for the promotion of cell
growth and it is transiently activated by cell growth signals and then converted
1km

Source: IEA World Energy Outlook 2019

Price reduction and spread of solar photovoltaic devices[Inﬂation adjusted Euros (2019)/Wp]
Module Price

100

10

Mega-solar/Giga-solar plant
1980

1990

Roof-top small-scale
power generation

2000

1

Smart houses

Fast-charging
stations2010
and electric vehicless

Cumulative production (GWp)

Up until 2000, improvements in conversion eﬃciency were a major factor in the reduced cost of solar
photovoltaic devices, but in the 2000s, the increased size of power plants also began to contribute to

Mutatio

Gene

Source : Google Earth

Figure 1:Discovery of an oncogene

Noor Abu Dhabi PV Power Plant, a gigawatt-level solar power plant in Abu Dhabi. This power plantis installed with the p-n junction crystalline silicon PERC cells invented by Prof. Green. PERC devices
are considered environmentally friendly because they can generate between 10 and 30 times theamount of energy required to produce the devices, depending on location and technologies used.
Figure 4:Ac
(Source: Google Maps）
Cancer cells
Cancerous cells

Introduction of extracted and fragmented
DNA into cancerous cells

Hole AppearanceElectron of cancer cell clones

2015

Large and small-scale solar power plants can be distributed throughout a region and can be tailoredto match the natural and urban environments of the area. Other types of renewable energy power
0.0
plants canalso be 0.1
constructed,
and if10the entire
systemis connectedby a smart grid, it can
0.001
0.01
1
100
1000
10000
redistribute power as needed and ensure continued power supply in the case of disaster .

PromFront contact
N-type silicon

Discovery of a mutated form of the gene encoding
the RAS protein

Recombination
p-n junctionNop5