the laser-dsr method - nist
TRANSCRIPT
The Laser-DSR Method
29.10.2015
New Developments in the Field of Primary Calibrations
of Reference Solar Cells
Overview
o Demand for high accuracy solar cell calibrations
o Standard Test Conditions
o DSR Method
o The new PTB setup: Advantages and disadvantages
o Validation by International Comparisons => WPVS
Economic Impact of Measurement Uncertainty for Photovoltaics
Source of data: EPIA (European Photovoltaic Industry Association) and for 2015 according to IHS market research institute
• Financial uncertainty = Global annual installation Price Uncertainty• 2012: Financial uncertainty = 30 GW/year 1.7 €/W 1 % = 500 M€/year
A measurement uncertainty of 1% leads to a financial uncertainty of 500 M€/year High demand for high accuracy solar cell calibrations
Solar parks are financed from banks, who add the financial uncertainty arising from measurement uncertainty to the total amount to be financed. A low uncertainty leads to competitive advantage.
Source of data: www.solarwirtschaft.de/preisindex
2006
2007
2008
2009
2010
2011
2012
0
1
2
3
4
5
Syste
m p
rices for
end c
usto
mers
in
Eu
ro / W
att
Prices in Euro/Watt
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015*0
10
20
30
40
50
Yearly w
orldw
ide n
ew
lyin
sta
lled P
V P
ow
er
/ G
W
New PV installations
Economic Impact of Measurement Uncertainty for Photovoltaics
Source of data: EPIA (European Photovoltaic Industry Association) and for 2015 according to IHS market research institute
To achieve lower uncertainties, in addition more realistic standards are needed
Energy rating instead of Maximum Power for PV classification (EMRP-Project PhotoClass) Energy rating approach needs much more parameters
• Temperature dependence• Non-Linearity• Angular dependency
Source of data: www.solarwirtschaft.de/preisindex
2006
2007
2008
2009
2010
2011
2012
0
1
2
3
4
5
Syste
m p
rices for
end c
usto
mers
in
Eu
ro / W
att
Prices in Euro/Watt
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015*0
10
20
30
40
50
Yearly w
orldw
ide n
ew
lyin
sta
lled P
V P
ow
er
/ G
W
New PV installations
Demand for a multifunctional calibration facilities
Standard Test Conditions
• Reference solar spectrum AM1,5
• Irradiance ESTC = 1000 W/m²
• Cell-Temperature (25°C)
• Angular distribution important, but not defined
The calibration procedure must take into account these STC according to IEC 60904-3.
Metrological background
,NormPhotocurrent: ( ) d( )E sI
Reference solar spectrum AM1.5 according to IEC 60904-3:2008
Spectral responsivity of different solar cells
200 400 600 800 1000 1200 1400 1600 1800Wavelength / nm
2468 135Photon energy / eV
0,0
0,2
0,4
0,6
0,8
Abso
lute
spec
tral
res
ponsi
vit
y, s
/ A
W-1
= 100%c-Si
GaInAs
CdTe
Poly-Si
CIS
a-SiGaInP
Ge Component Cell
400 600 800 1000 1200Wavelength, / nm
0
500
1000
1500
2000
2500
Sp
ectr
al i
rrad
ian
ce E
/
mW
m-2
nm
-1
AM1.5 (IEC 60904-3:2008)
Metrological background
,NormPhotocurrent: ( ) d( )E sI
Reference solar spectrum AM1.5 according to IEC 60904-3:2008
Spectral responsivity ofdifferent solar cells
200 400 600 800 1000 1200 1400 1600 1800Wavelength / nm
2468 135Photon energy / eV
0,0
0,2
0,4
0,6
0,8
Abso
lute
spec
tral
res
ponsi
vit
y, s
/ A
W-1
= 100%c-Si
GaInAs
CdTe
Poly-Si
CIS
a-SiGaInP
Ge Component Cell
400 600 800 1000 1200Wavelength, / nm
0
500
1000
1500
2000
2500
Sp
ectr
al i
rrad
ian
ce E
/
mW
m-2
nm
-1
Sun simulator with AM1.5 filterfrom its data sheet
AM1.5 (IEC 60904-3:2008)
Comparison of integral and spectral measurements
Integral Measurement Spectral Measurement
Spectrum can not be interpolated+ Spectral responsivity can be
interpolated
Uncertainty due to the measurement of the spectrum, e.g. spectral straylightwithin the spectroradiometer
+ The AM1.5 spectrum of the standard can be used directly
=> No uncertainty component
+ High signal Low signal,NormPhotocurrent: ( ) d( )E sI
200 400 600 800 1000 1200 1400 1600 1800Wavelength / nm
2468 135Photon energy / eV
0,0
0,2
0,4
0,6
0,8
Abso
lute
spec
tral
res
pon
sivit
y, s
/ A
W-1
= 100%c-Si
GaInAs
CdTe
Poly-Si
CIS
a-SiGaInP
Ge Component Cell
400 600 800 1000 1200Wavelength, / nm
0
500
1000
1500
2000
2500
Sp
ectr
al i
rrad
ian
ce E
/
mW
m-2
nm
-1
Sun simulator with AM1.5 filterfrom its data sheet
AM1.5 (IEC 60904-3:2008)
Solar cell
Bias radiationEb
Modulated monochromatic
radiation, measured with Ref.-PD
DE()
Ib + DIsc(, Eb)
DC-Multimeter + Lock-In-Amplifier
DSR-Method Differential Spectral Responsivity
0 20 40 60Time t
ms0
2
4
6
8
10
Irra
dia
nce
E
: Monochromatic + bias radiation
: Bias radiation
𝑠 𝐸𝑏 =∆𝐼(𝜆, 𝐸𝑏)
∆𝐸
=d𝐼
d𝐸
∆𝐸 ≪ 𝐸𝑏
Result of DSR measurement
Absolute differential spectral responsivity ~s (, I(E)) of polycrystalline Si solar cell
400 600 800 1000 1200
Wavelength, in nm
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
~ sab
s i
n
mA
W /
m²
0.01 0.1 1 10 100I in mA
0.1 1 10 100 1000E in W / m²
75
80
85
90
95
~ s i
n
mA
10
00 W
/ m
²
-20%
-15%
-10%
-5%
0%
5%
Polycrystalline Si
AM1.5( ) ( ) dE s s =
𝐼STC
0𝐼STC 1
𝑠(𝐼)d𝐼
Calibration objects
Reference solar cells
200 400 600 800 1000 1200 1400 1600 1800Wavelength / nm
2468 135Photon energy / eV
0,0
0,2
0,4
0,6
0,8
Abso
lute
spec
tral
res
ponsi
vit
y, s
/ A
W-1
= 100%c-Si
GaInAs
CdTe
Poly-Si
CIS
a-SiGaInP
Ge Component Cell
Component solar cells for Space Application
Laboratory method instead of balloon flight
Calibration objects
Industry solar cells
absolute differenzielle spektrale Empfindlichkeiten ~s (, I(E)) von ISFH Referenz
400 600 800 1000 1200
Wellenlänge, in nm
0
2
4
6
8
10
12
14
16
~ sab
s in
m
A
W /
m²
0%
1%
2%
3%
4%
5%
rel.
Un
sich
erhei
tk=
2
: I = 27,4 mA 30
: I = 191,6 mA 32
: I = 1010,1 mA 34
: I = 2887,4 mA 35
: I = 4481,8 mA 36
: s(, 1000 W/m²)
: Ableitung
Validation of the DSR method for non Si responsivities
• Comparison of component solar cells with “extraterrestrial” calibration by ESA
• The results agree within 0.4% and 0.6%.
300 400 500 600 700 800 900Wavelength, / nm
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
~ sab
s /
mA
W /
m²
C. Baur, G. Siefer, R. Kern, S. Winter: “Primary solar cell standards – comparison of extraterrestrial and synthetic calibration”, in Proceedings of “9th European Space Power Conference (ESPC)”, (Saint Raphael, Juni 2011)
Realisation und maintainance of the„World Photovoltaic Scale“
NREL
PTB
TIPS
AIST
EURAMET supplementary comparison S.5
o Started in 2013, Draft A this year
o Star-like order: Participant -> PTB -> Participant
o Calibration of Isc under STC
o Participants
o PTB (Coordinator)
o VNIIOFI
o KRISS
o A*STAR
o ITRI
o NIM
o Asked for participation in the next round: NIST
How to measure the Differential Spectral Responsivity
o Xenon or quartz halogen lamp based system (DSR, SCF)(or laser-driven xenon lamps or supercontinuum systems)
+ Easy to use
Low Power (100 µW) with subsequent problems
Uniformity
Large bandwidth
Bad Signal-To-Noise especially at high bias levels
Rel. & abs. measurement needed
Size of the solar cells is limited
S. Winter, T. Wittchen, J. Metzdorf in Proc. 16th EU PVSEC, (Glasgow 2000)
The new Laser-DSR setup
o Tunable laser substitutes lamps
Power increases up to a factor 100 – 10000
+ Good uniformity
+ Low bandwidth possible
+ No interpolation between relative and absolute measurement
monitorphotodiode
Bias lamps with dichroic mirrors for absolute calibration
Absolute spectral responsivity
ModelockedTi:Sapphire
laser
Optical parametricOscillator (OPO),SHG, THG, FHG
Pulse-to-CWconverter
Bandpasslimitation
(monochromator)
Pulsed with 80 MHz CW signal
680 nm – 1080 nm 190 nm – 4000 nm
Many further improvements in detail
x,y,z-Table
Monochromator
Optics (Lenses,
Apertures,
Monitor phodiode)
Biasradiator
Φ-θ-Goniometer
Pulse-to-CW
Convertor
(Fiber)
Chopper
Climate Chamber
Lasersystem
(Ti:Saphir Laser,
OPO, SHG, THG,
FHG)
Electronic
Compact Array
Spectroradiometer
Scientist
PhD-Student
Design of the new Facility
x-y-z-Table + GoniometerLaser systemBias RadiationOptics
Laser-DSR- Facility: From Design to Realisation
200 400 600 800 1000 1200 1400 1600
wavelength, / nm
1234567 1,5
photon energy / eV
10-4
10-3
0,01
0,1
1
10
100
1000
104
105
106
107
op
tica
l pow
er /
µW
GW: switch of monochromator grating
: DSR Xenon - lamp, incident on solar cell, measured with Si-PD
: DSR FEL-lamp, incident on solar cell, measured with thermocolumn
: LDSR, incident on solar cell, measured with powermeter
: LDSR, direct laser output, measured with powermeter
• Factor 100-10 000 higheroptical power than with theold facility
• Spectral range 200-1600nm
Measurement results: Radiation power
Conclusion
o DSR method is well suited for the primary calibration
of different types of solar cells
o The method is validated for many different
stable single junction solar cells
o PTB develops the next-generation of the DSR facility:
LASER-DSR
o The high power improves the signal to noise ratio and
enables higher resolution and better uniformity
o It is a multipurpose spectral comparison facility.
s = s(, E, fChopper, T, x, y, z, , )
Conclusion
Thank you for your attention
A part of the work was funded by EMRP.
The EMRP is jointly funded by the EMRP participating
countries within EURAMET and the European Union.
“Towards an energy-based parameter for photovoltaic classification”
The new Laser-DSR setup
o Tunable laser substitutes lamps
Power increases up to a factor 100 – 10000
+ Good uniformity
+ Low bandwidth possible
+ No interpolation between relative and absolute measurement
monitorphotodiode
Bias lamps with dichroic mirrors for absolute calibration
Absolute spectral responsivity
ModelockedTi:Sapphire
laser
Optical parametricOscillator (OPO),SHG, THG, FHG
Pulse-to-CWconverter
Bandpasslimitation
(monochromator)
Pulsed with 80 MHz CW signal
680 nm – 1080 nm 190 nm – 4000 nm
Why do we need a monochromator behind the laser?
The new Laser-DSR setup
o Tunable laser substitutes lamps
Power increases up to a factor 100 – 10000
+ Good uniformity
+ Low bandwidth possible
+ No interpolation between relative and absolute measurement
monitorphotodiode
Bias lamps with dichroic mirrors for absolute calibration
Absolute spectral responsivity
ModelockedTi:Sapphire
Laser
Optical parametricOscillator (OPO),SHG, THG, FHG
Pulse-to-CWConverter
Bandpasslimitation
(Monochromator)
Pulsed with 80 MHz CW signal
680 nm – 1080 nm 190 nm – 4000 nm
Pulse to cw converter
L0 = l0L1 = l0 + 2.5 cmL2 = l0 + 5.0 cmL3 = l0 + 7.5 cm…
L99 = l0 + 247.5 cm
t0 = t0
t1 = t0 + 0.125 nst2 = t0 + 0.250 nst3 = t0 + 0.375 ns…
t99 = t0 + 12.375 ns
And after 12.5 ns the next pulse from the laser appears.
Fiber bundle with 100 multimode fibers , each with an individual length
12.5 25 37.5 4
Time / ns
0.0
0.2
0.4
0.6
0.8
1.0
Sig
nal
: Laser Signal
: Signal with
"Pulsed in
cw-Converter"
Pulse to cw converter
Fiber 1
Fiber 1 andFiber 50
Fiber 1, 33 and 66
Fiber 1, 25, 50 and 75
Pulse to cw converter
All 100 fibers