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Cell Data Sheet Specification 

2012 PV Module Reliability 

Workshop

Golden, CO

Sarah Kurtz 

NREL

March 1, 2012

NREL/PR-5200-54566
 NATIONAL RENEWABLE ENERGY LABORATORY

Motivation for Creating Specification of 

Concentrator Cell Data Sheet

• Provide more consistency and complete info 

for customers wishing to compare cells

• Provide basis for defining temperature 

coefficients to be used for relating power rating 

under test conditions and operating conditions 

(cell T = 25°C vs ambient T = 20°C)

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T=25°C T=40-70°C

T(ambient)=20°C
 NATIONAL RENEWABLE ENERGY LABORATORY

Status of Specification

• Is approved as new work item

• Draft will be discussed in April at WG7 

meeting

• As technical specification, if approved by 

WG7 in April, it will be submitted and could 

be approved (go to print) as early as next 

fall.

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Next slides show proposed specification
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Manufacturer The XYZ Company

Model Number XX1090

Type of Cell Three junction: GaInP(1.89 eV) 

/GaInAs (1.39 eV)/Ge (0.67 eV) 

on germanium substrate

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Product Identification
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Cell Area 1.1 cm X 1.0 cm

Active area

Simulator active area

1 cm X 1 cm (see sketch)

1.01 cm2

Nominal efficiency 39%±2% 

Nominal current ratios Ratio for 1.39 eV/1.89 eV = 1.0 ± 0.03

Ratio for 0.67 eV/1.89 eV = 1.7 ± 0.03

Temperature coefficients 

(measured at the irradiance for 

which the product was 

designed)

α = dIsc/dT = + 0.11%±0.03%/°C when top-cell limited; 

+0.07%±0.03%/°C when bottom-cell limited

β = dVoc/dT = -0.15%±0.02%/°C

dPmax/dT = -0.24%±0.06%°C

Measured at 100 W/cm2; AM1.5 Direct; temperature 

range of 25°C to 70°C. Other conditions may also be 

documented.

Front metallization Silver

Front metallization thickness 1 μm

Back metallization Gold 

Maximum current 1 A/cm2

Anti-reflection coating design Matched to index of 1.4

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Product Description
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Recommended operating 

temperature 

-20 °C < T < 150°C

Recommended processing 

temperature

< 350°C for 10 min

Chemical compatibilities/ 

incompatibilities

?

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Cell processing and use conditions
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Typical I-V curve Measured at 50 W/cm2; AM1.5 Direct spectrum; 

25°C. Isc, Imp, Vmp, Voc, FF, Efficiency 

specified

Efficiency as function of 

irradiance

Plotted/tabulated as function of irradiance for 

25°C, 40°C, 60°C, and 80°C; AM1.5 

Direct spectrum

Voltage at maximum power 

point

Plotted/tabulated as function of irradiance for 

25°C; AM1.5 Direct spectrum

Efficiency distribution for fullwafer productionFraction of population in 0.25% efficiency bins 

using manufacturers choice of conditions; 

indicate number of cells measured

Quantum efficiency 

(preferably presented as both 

a graph and a table)

One curve for each junction, measured at 

25°C

Angular responsivity Isc as a function of incidence angle compared 

with cosine function

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Graphs/Tables
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LIV test Example conditions:

50 W/cm2; AM1.5D; 25°C; 100% 

of samples

Thermal cycling – IEEE 1513 < 10% loss in efficiency after 500 

cycles from -40°C to +110°C

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Cell testing and screening conditions
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Sarah.Kurtz@nrel.gov

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Please send your 

questions, comments and 

suggestions 

by April 10, 2012 

to:

Cell Datasheet description will provide 

for more consistent and complete 

characterization of concentrator cells