Post on 19-Aug-2020
Solar cell innovations by nanolayers
Erwin Kessels
w.m.m.kessels@tue.nlwww.tue.nl/pmp
Presentation prelude• In the Netherlands, we have a rich tradition and a strong position in the field of thin film materials
o Also for the field of solar energyo Both academically and industrially
• Many technological innovations driven by advances in “materials”o Also true for solar cellso Currently strong focus on nanoscale materials
• In this presentation: discuss how solar cell innovations have been enabled by nanolayers and will continue doing so!
• Will do so from a personal perspective and by taking big leaps
Outline – trends to be discussed#1 From Al‐BSF to PERC cells
#2 PECVD and ALD Al2O3 passivation layers
#3 Towards n‐type silicon cells
#4 Towards silicon heterojunction cells
#5 Towards interdigitated back‐contact cells
#6 Towards silicon based tandem cells
#7 Towards perovskite solar cells
The Al-back-surface-field (Al-BSF) solar cell
The Al-back-surface-field (Al-BSF) solar cell
SiNx antireflection coating
Diffused n+ region
Textured p‐type silicon
Al back‐contact
Ag front‐contact
PERC enabled by passivating Al2O3 nanolayers
Bram HoexJunior Einstein Award
2008
Hoex et al., Appl. Phys. Lett. 89, 042112 (2006).Review paper: Dingemans et al., J. Vac. Sci. Technol. A 30, 040802 (2012).
Excellent passivation: breakthrough by ALD Al2O3
Department of Applied Physics – Erwin Kessels
Injection Density n (cm-3)1012 1013 1014 1015
Effe
ctiv
e Su
rface
Rec
ombi
natio
n Ve
loci
ty S
eff (
cm/s
)
1
10
100
1-2 cm FZ p-Si
SiNx
a-Si
Al2O3
Al2O3
1.5 nm SiOx
c-Si
Al2O3 nanolayers (~5 nm) lead to excellent passivation of silicon surfacesDue to: 1) passivation of Si defects by H; 2) shielding of electrons by fixed charge
H H H H H
Qf― ― ― ― ―
Hoex et al., Appl. Phys. Lett. 89, 042112 (2006).Dingemans et al., J. Vac. Sci. Technol. A 30, 040802 (2012).
HH
H
Atomic layer deposition of Al2O3
Department of Applied Physics – Erwin Kessels
First PERC cells with Al2O3 nanolayers
Front metal grid Random pyramids
n + emitterN
P p -Si base
Point contacts
AluminiumAl O or Al O /SiO stack2 3 2 3 x
SiNx
n+ emitter
p-Si base
Front metal grid Random pyramids
n + emitterN
P p -Si base
Point contacts
AluminiumAl O or Al O /SiO stack2 3 2 3 x
SiNx
n+ emitter
p-Si base
Schmidt et al., Prog. Photovolt. Res. Appl. 16, 461 (2008).
Worldwide PERC capacity 2017
Department of Applied Physics – Erwin Kessels Courtesy of Morgan Ku (March 2, 2017)
PERC (Passivated emitter rear cell)
Performance loss induced by LeTID in the field | Friederike Kersten | 33rd EU PVSEC Amsterdam, September 27, 201712
Hanwha Q CellsGlobal Operation for R&D and Production
Germany- Global R&D Center (>210)- Global QM- VDE Lab (in-house)
Germany- Global R&D Center (>210)- Global QM- VDE Lab (in-house)
Malaysia- Capacity (2016YE):
Cell 1,800MWModule 1,800MW
Malaysia- Capacity (2016YE):
Cell 1,800MWModule 1,800MW
China (QD)- Capacity (2016YE):
Cell 2,400 MWModule 2,400 MW
China (QD)- Capacity (2016YE):
Cell 2,400 MWModule 2,400 MW
China (LYG)- Capacity (2016YE):
Ingot 1,500 MWWafer 900 MW
China (LYG)- Capacity (2016YE):
Ingot 1,500 MWWafer 900 MW
Korea- Capacity (2016YE):
Cell 2,100 MWModule 2,100 MW
Korea- Capacity (2016YE):
Cell 2,100 MWModule 2,100 MW
Engineering- Continuous improvement- Product development
Engineering- Continuous improvement- Product development
Engineering- Continuous improvementEngineering- Continuous improvement
Engineering- Crystallization- Continuous improvement
Engineering- Crystallization- Continuous improvement
Engineering- Continuous improvementEngineering- Continuous improvement
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
5,500
6,000
6,500
CELL MODULE
6.3 GW* 6.3 GW*
* As
per e
nd o
f Q2,
201
7
*Capacity in South Korea belongs to affiliated and non‐listed company Hanwha Q CELLS Korea Corporation
Gijs DingemansWinner Solar Thesis Award 2012
Spatial ALD for Al2O3 - SolayTec
Department of Applied Physics – Erwin Kessels SolayTec B.V. ‐ www.solaytec.com
Top viewSide view Wafer moves hence and forth
Spin‐off from TNO (2010)Now part of the Amtech group
System throughput:Up to 4800 wafers/hr
Spatial ALD for Al2O3 - Levitech
Department of Applied Physics – Erwin Kessels Levitech B.V. ‐ www.levitech.nl
Cross‐sectional viewSide view Wafer from one side to the other
Spin‐off from ASM International (2009)
System throughput:Up to 6000 wafers/hr
First cell with p+-emitter passivated by ALD Al2O3
Hoex et al., Appl. Phys. Lett. 91, 112107 (2007).Benick et al., Appl. Phys. Lett. 92, 253504 (2008).
Article in newspaper NRC Handelsblad
STW perspectief project: Flash
ALD of high‐mobility transparent conductive oxides (TCOs)
1.5 2.0 2.5 3.0 3.5 4.00
2
4
6
8
10
12
Photon energy (eV)
Abso
rptio
n co
effic
ient
(104 c
m-1)
0
10
20
30
40
50
Free-carrier absorption
Photon flux (mA/m
2/eV)
Solar spectrum In2O3:H
ITO
1.12Eg,c-Si
1.5 2.0 2.5 3.0 3.5 4.00
2
4
6
8
10
12
Photon energy (eV)
Abso
rptio
n co
effic
ient
(104 c
m-1)
0
10
20
30
40
50
ZnO:BZnO:H
Free-carrier absorption
Photon flux (mA/m
2/eV)
Solar spectrum
ZnO:Al
1.12Eg,c-Si
ALD In2O3:H
ALD ZnO:Al75 nm 40 nm
Macco et al., Phys. Status Solidi RRL 8, 987 (2014).Macco et al., Semicond. Sci. Technol. 29, 122001 (2014).
Application of ALD ZnO:Al at rear side SHJ cell
Department of Applied Physics – Erwin Kessels
AZODMAI (low)
ITO
η (%) 21.30 21.33
Voc (mV) 731.9 733.7
Jsc(mA/cm2) 36.67 36.47
FF (%) 79.38 79.71
Si heterojunction cellwith ZnO:Al at the rear
Abundant ZnO:Al as good as more expensive ITO
(but not yet at the front)
Niemelä et al., to be published (2018).
Passivating contact cellsCells with metal contacts separated from silicon through passivation layer
A simple concept: “Just depositing stacks of thin films on silicon”
Passivating contact cells
c-Sic-Si
SiOxSiOxTiOxTiOx
Many new materials: doped poly‐Si, metal fluoriudes, metal oxides, …
TKI Urban Energy projects: Compass, Miracle, Radar, …
Cells with metal contacts separated from silicon through passivation layer
Preferably with highly transparant and stable nanolayers!
A simple concept: “Just depositing stacks of thin films on silicon”
TU/e solar family car “Stella Vie”
See our blog post at: www.AtomicLimits.com
IBC cells from
SiNx antireflection coatings prepared by the DEPxDEPx fast deposition system with expanding thermal plasma source
(developed at TU/e)
OTB Solar B.V. Roth & Rau B.V. Meyer‐Burger B.V.(known from SiNA & MAiA)
2010 2011
See our blog post at: www.AtomicLimits.comwww.meyerburger.com
Joint Solar Programme IIINew project on high‐efficiency hybrid tandem solar cells
started in September 2017
Metallization & light management
Organic and inorganic perovskites
Nanolayers & passivation
Tandem architecture & silicon cell
Note: project focuses on 4‐terminal cell with IBC silicon bottom cell
Silicon-perovskite tandem cells with ALD
Department of Applied Physics – Erwin Kessels Bush et al., Nature Energy 2, 17009 (2017).Koushik et al., to be published (2018).
Stanford‐ASU‐MIT‐etc.
2‐terminal devicewith ALD SnO2:
23.6% efficiency (certified)
4‐terminal devicewith ALD In2O3:H
22.6% efficiency
ALD SnO2/ZTO
Top cell:‐ Triple cation perovskite ‐
glass
ALD In2O3:HNiO NPs
Perovskite
PCBM/ZnO NPs/ZnO
ITO
Bottom cell:‐Metal‐wrap‐through c‐Si(n) cell ‐
Perovskite cells with nanolayers
TCOIn2O3, ZnO:Al, ZnO:B, …
Electron transport layerTiOx, SnOx, …
Passsivation layersAl2O3, …
Hole transport layerNiOx, CuOx, MoOx, WOx, …
Zardetto et al., Sust. Energy Fuels 1, 30 (2017).
Perovskite with ALD Al2O3 nanolayer
0.0 0.2 0.4 0.6 0.8 1.00
5
10
15
20
Cur
rent
Den
sity
(mA
/cm
2 )
Voltage (V)
Pristine 8 cycles 10 cycles 15 cycles 18 cycles 20 cycles
Glass
TiO2
CH3NH3PbI3-δClδ
Spiro-O-MeTAD
ITO500 nm
Au
No. of cycles Voc(V)
Jsc(mA/cm2) FF PCE
(%)
0 1.03 21.3 0.69 15.1
8 1.07 20.8 0.78 17.4
10 1.08 21.7 0.77 18.0
15 1.07 21.7 0.77 17.9
18 1.02 19.5 0.69 13.7
20 0.96 16.0 0.63 9.7
3% absolute increase in efficiency with 10‐15 cycles Al2O3
Koushik et al., Energy & Envir.Science, 10, 91‐100 (2017).Koushik et al, Advanced Mat. Interfaces 1700043 (2017).
Perovskite with ALD Al2O3 nanolayer
Glass
TiO2
CH3NH3PbI3-δClδ
Spiro-O-MeTAD
ITO500 nm
Au
Koushik et al., Energy & Envir.Science, 10, 91‐100 (2017).Koushik et al, Advanced Mat. Interfaces 1700043 (2017).
0.0 0.2 0.4 0.6 0.8 1.0 1.20
5
10
15
20
25
Cur
rent
Den
sity
(mA
/cm
2 )
Voltage (V)
pristine 10 Al2O3 cycles
0 10 20 30 40 50 60 700
5
10
15
20 pristine 10 cycles Al2O3
PCE
(%)
no. of days
Ageing studies: Al2O3 significantly delays cell degradation
Roll-to-roll ALD
Poodt et al., J. Vac. Sci. Technol. A 30, 01A142 (2012)Meyer‐Burger B.V. ‐ www.meyerburger.com
Summary• Nanolayers have enabled important innovations in the field of crystalline silicon photovoltaics most prominently: Al2O3!
• Many more opportunities exist for (ALD) nanolayers:o Crystalline silicon (e.g. passivated contacts)o Perovskiteso Tandem solar cellso …
Passivated contacts solar cell Perovkite solar cell
Passivating contact workshop ‐ January 31, 2018 – TU/e Eindhoven
Department of Applied Physics – Erwin Kessels
Acknowledgments
Plasma & Materials Processing groupPhD students/postdocs/faculty involved:Willem‐Jan BerghuisDibya KoushikDr. Bas van der LooDr. Yizhi WuDr. Bart MaccoDr. Sjoerd SmitDr. Gijs DingemansDr. Bram Hoex
Dr. Jimmy MelskensDr. Yinghuan KuangDr. Lachlan BlackDr. Janne NiemeläDr. Diana GarciaDr. Valerio ZardettoDr. Adriana CreatoreDr. Marcel Verheijen
Plasma & Materials Processing group