Solar Cell Evaluation System

Model UV-Visible-NIR Spectrophotometer

This system is designed for sample measurement in the UV region. The system uses a light source, a grating,

and an integrating sphere that are specifically designed for UV measurements, and provides measurements

with a superior S/N ratio in the UV region when compared with other systems.

Through a nitrogen purge of the photometer, the deep UV region starting at 175 nm can also be measured. In

addition, because it does not require a nitrogen purge of the sample compartment, the system eliminates the

wait time for re-purging after a sample is replaced, which allows for the measurement of multiple samples in a

short period of time.

1

Solid Sample Measurement System

Ultraviolet Region Measurement System

Large Sample Measurement SystemThis system affords the non-destructive transmittance/reflectance measurement of various optical

and electronic materials, including large-sized glass, silicon wafers, and liquid crystal substrates,

beyond the measurement of solar cell components.

This system is designed for transmittance/reflectance measurement of solid samples. You can build a system

that is well-suited for a particular measurement purpose by combining the system with a variety of accessories,

such as a specular reflection device.

Spectrometer: prism-grating. Sample compartment: standard sample compartment.

Detector: standard integrating sphere. Measurement wavelength range: 240 to 2,600 nm.

Maximum sample size: 200 × 200 mm.

With the Model U-4100 Spectrophotometer, you can select an optimal the transmittance and reflectance of various materials that compose

System

Configuration

Spectrometer: prism-grating. Sample compartment: large-size compartment.

Detector: standard integrating sphere. Measurement wavelength range: 240 to

2,600 nm. Maximum sample size: 430 × 430 mm.

System

Configuration

Spectrometer: grating/grating. Sample compartment: standard compartment.

Detector: high-sensitivity integrating sphere. Measurement wavelength range: 175 to 2,600 nm.

Maximum sample size: 200 × 200 mm.

System

Configuration

Referencebeam

Optical axis

Sample compartment (top view)

Sample compartment (top view)

Sample compartment (side view)

Sample compartment (side view)

Samplebeam

Referencebeam Optical axis

Samplebeam

Referencebeam

Optical axis

Samplebeam

Sample compartment (top view)

Sample compartment (side view)

＊1: Not applicable to samples having a light-scattering property.

2

System applied to

Large UVSolidAccessory Example

system for the measurement of solar cells.

5 deg. specular reflectance accessory (absolute)

Top-mount transmittance/reflectance measurement unit

Variable-angle transmittance measurement accessory

Variable-angle absolute reflectance accessory (10 deg. step type)

Variable-angle absolute reflectance accessory (fully variable type)

U-4100 Spectrophotometer(Large Sample Measurement System)

Choose from a wide range of accessories to configure a system best suited for your application.

5 deg. specular reflectance accessory (absolute)(134-0102)

Top-mount transmittance/reflectance measurement unit(134-0107 (0 deg. transmittance, 5 deg. reflectance))

(134-0108 (0 deg. transmittance, 12 deg. reflectance))

Variable-angle transmittance measurement accessory(134-0200)

Variable-angle absolute reflectance accessory (10 deg. step type) (134-0116 (10-60 deg. reflectance))

(134-0117 (15-65 deg. reflectance))

Variable-angle absolute reflectance accessory (fully variable type)(134-0115 (20-60 deg. reflectance))

Measures the reflectance and transmittance at a 5 deg. incident angle and

verifies the effect of an anti-reflection film or calculate＊1 the rate of absorption

from reflectance measurements (see P. 3).

Measures the reflectance and transmittance of large samples up to 300 × 300

mm. Allows the evaluation of in-plane transmittance and reflectance of glass

substrates and transparent conductive films for solar cells.

Measures transmittance by changing the incidence angle. Allows the

measurement of change in transmittance characteristics of a solar cell

substrate by varying the incident angle.

Measures reflectance and transmittance at 10 deg. intervals by varying the

incident angle and verifies the effect of an anti-reflection film, or calculate＊1 the

rate of absorption from transmittance or reflectance measurements (see P. 4).

Measures reflectance and transmittance at any angle between 20 and 60 deg.

by changing the incidence angle.

Allows the measurement of distribution of scattering angles on light transmitted

by glass substrates and other objects having a texture structure (see P. 5).

Measurement of an Anti-Reflection Film

In order to enhance the efficiency of power generation, polysilicon solar cells incorporate

anti-reflection films designed to efficiently direct sunlight onto the power generation

layer of the semiconductor so that the light will not escape as reflected rays.

The use of a 5 deg. specular reflectance accessory permits the verification of the effect of

an anti-reflection film at an incident angle close to perpendicular with respect to the sample.

The graphs shown below represent measurements of reflection spectra from substrates

provided with visible and NIR-region anti-reflection films. Both cases indicate the

presence of a wavelength region with an extremely low reflectance. It is clear that in the

wavelength region very little light is lost due to reflection.

The U-4100 Spectrophotometer, incorporating an optical system optimized for the prism

grating spectrometer, is capable of accurately measuring spectra while minimizing noise.

The 5 deg. specular accessory, through the adoption of an optical system called the V-N process, can measure both transmittance and reflectance of the same

spot on a given sample, which makes it well-suited for the measurement of transmittance and reflectance on the same spot in a sample characterized by

surface irregularities. The ability to take measurements on the same spot permits the accurate determination of the absorbency＊1 of the sample from

transmittance/reflectance measurement results.

Polysilicon solar cell

Incident light Reflected light

Measurement mode: reflectance, transmittanceIncident angle: 5 deg.Sample size: reflectance (25 to 50 mm diameter, 25 × 25 to W100 × H150 mm) transmittance (25 to 45 mm diameter, 25 × 25 to W45 × H150 mm)Wavelength range: 240 to 2,600 nm

5 deg. specular reflectance accessory (absolute)(134-0102)

5 deg. specular spectrum for a substrate provided with an anti-reflection film

Optical system for the 5 deg. specular accessoryTransmittance measurement Reflectance measurement

3

1Anti-reflection film

p-type silicon

n-type silicon

Irradiationlight

Sample

Mirror A

Mirror B

Detector

Irradiationlight

Sample

Mirror BDetector

Mirror A

For visible light region

Reflectance (%R)

15

10

5

0

Wavelength (nm)400 500 600 700 800

For NIR region

Reflectance (%R)

10

5

0

Wavelength (nm)1,000 1,250 1,500 1,750 2,000

＊1: Not applicable to samples having a light-scattering property.

4

Measurement of a Substrate with a Transparent conductive Film

The adoption of the V-N process permits the measurement of both transmittance and reflectance on the same spot.

Measurement of transmittance and reflectance with varying incident angle is possible, from the UV region (240 nm) and beyond.

20°Incident light

40°

60°

Transmitted light

Measurement mode: reflectance, transmittanceIncident angle: 10 to 60 deg. (134-0116, in 10 deg. steps) 15 to 65 deg. (134-0117, in 10 deg. steps)Sample size: reflectance (8 × 8 to W90 × H100 mm＊3) transmittance (8 × 8 to W90 × H100 mm＊3)Wavelength range: 240 to 2,600 nm

＊3: At the 60 deg. and 65 deg. incident angles, the sample size will be 21×21 to W90×H100 mm.

＊Measurement requires a separately purchased polarizer.Variable-angle absolute reflectance accessory

(10 deg. step type)(134-0116, 134-0117)

Substrate with a transparent conductive film

Substrate with a transparent conductive film

2

20°Incident light

40°

60°

Reflected light

Incidentangle20 deg.40 deg.60 deg.

Solar radiationtransmittance77.9 ％76.9 ％70.5 ％

Solar radiationreflectance14.2 ％15.1 ％20.2 ％

The thin-film silicon solar cell uses transparent conductive films as electrodes. In order to extract electricity, the transparent conductive film must have

desired conductivity and light transmittance.

Sunlight is subject to change in incident angle according to time of the day or seasons. Critical to the evaluation of light transmittance is the ability to

perform evaluations by varying the incident angle. The table on the right shows the results of calculation＊2 of solar radiation transmittance and reflectance

from measurements of transmittance and reflectance spectra by varying the incident angle over a range from 20 to 60 deg., using a substrate with a

transparent conductive film as a sample.

The results indicate that the solar radiation transmittance diminishes as the

incident angle increases, and the solar radiation reflectance increases. In this

manner, the use of a variable-angle absolute reflection accessory (the 10 deg.

step type) provides the quantitative measurement of transmittance and

reflectance characteristics with varying incident angles.

＊2: The calculation of solar radiation transmittance and reflectance requires a separate optional package.

Reflectance spectrum for a transparent conductive film substrate

Wavelength (nm)

20°40°60°

Wavelength (nm)400 600 800 1,000 1,200 1,400 1,600 1,800 2,000

60

80

100

20

40

0

Transmittance (%T)

20°40°60°

400 600 800 1,000 1,200 1,400 1,600 1,800 2,000

60

80

100

20

40

0

Reflectance (%R)

Transmittance spectrum for a transparent conductive film substrate

Calculation of solar radiation transmittance and reflectance＊2

Measurement of Textured Glass

Measuring Transmittance in All Directions

Measurement mode: Transmittance (permits measurements including diffusion transmittance)Sample size: 30 × 30 to 100 × 100 mmWavelength range: The same as the specifications for Model U-4100 systems

5

3In order to increase power generation efficiency, a fine pyramid structure called the

texture structure is formed on the light-receiving surface of monosilicon and the glass

panel of a solar cell. The formation of this structure causes the light entering the power

generation layer to repeatedly undergo transmission, reflection, and scattering. As a

result, more light can be directed to the power generation layer when compared with a

flat surface, thus enhancing power generation efficiency.

Such a structure must satisfy the requirements of light diffusion and high transmittance.

Critical to the accurate measurement of the transmittance is the tight adhesion of the

sample to the integrating sphere. The use of a transmission holder (tight adhesion)

permits the strong adhesion of the sample to the integrating sphere and the

measurement of transmittance including diffusion transmittance.

The above graph shows the measurement of the transmittance of a glass panel

having a light-diffusion structure in two situations: with a sample tightly attached

to the integrating sphere and a sample off the integrating sphere. The results

indicate that the tight adhesion of the sample produces high transmittance, and

permits measurements including diffusion transmittance.

Measuring transmittance including diffusion transmission

Example of a solar cell with a texture structure

By tightly attaching the sample to the integrating sphere, it is possible to

measure transmittance including diffusion transmittance.

Transmission holder (tight attachment)(1J0-0202)

Detector (integrating sphere)

Transmission holder(tight attachment)

Sample

Incident light

Incident light

Transmitted light

Detector(integrating sphere)

Sample

移動可能

Measuring the transmittance of a glass panel

Sample tightly attached to the integrating sphere

Sample off the integrating sphere

100

80

60

20

40

0

Transmittance (%)

Wavelength (nm)500 1,000 1,500 2,000 2,500

Light irradiation inside a solar cell

Glass

Transparent conductive film

α.Si.H layer

Measuring the Angle Distribution of Diffusion Transmission Light

6

(1) Permits the measurement of transmittance and reflectivity by varying the incident angle

(2) Permits the measurement of the angle distribution of diffusion transmitted lightThe accessory, which is designed to directly detect diffusion transmitted light through the use of an integrating sphere without using a mirror between the sample and

the integrating sphere, can accurately measure the angle distribution of diffusion transmitted light.

(3) Capable of stable measurement for long hoursBecause it incorporates an optical system that detects sample light and reference light in the same integrating sphere, the accessory permits stable measurements for long hours.

Transmittance, reflectanceIncident angle: 0 to 60 deg. (transmission)　　　　　　 20 to 60 deg. (reflection)

Angle distribution of diffusion transmitted lightIncident angle of sample: 0 to 60 deg.Detection angle: 0 to 140 deg.

Sample size: 30 × 30 to 90 × 90 mmWavelength range: 340 to 2,600 nm＊Measurement requires a separately purchased polarizer.

Variable-angle absolute reflectance accessory (fully variable type)(134-0115)

The evaluation of the angle distribution of diffusion transmission light has a great impact on the evaluation of a sample having a texture structure.

The variable-angle absolute reflection device (the fully variable type), which permits changing angles centered on the sample position, allows the user to measure the

distribution of the extent to which the diffusion transmission spreads. In particular, this device, which is designed to directly detect diffusion transmission light without

the use of a mirror, can accurately perform measurements in tenuous detection light regions.

The above graph shows the measurement of angle distribution of diffusion

transmitted light from three types of glass panels. It is clear that Glass A

produces the diffusion of transmitted light to the highest angle of direction.

Measuring the angle distribution of diffusion transmission light

By moving the detector with an integrating sphere mounted and measuring

the amount of light detected, the user can measure the distribution of the

extent to which the diffusion transmission spreads.

Incident light

Transmitted light

Detector(integrating sphere)

Movable

Sample

Sample holder

Incidentlight

Detector (integrating sphere)

移動可能移動可能Movable

Measuring the angle distribution of diffusion transmitted light from various glass panels

Glass A

Glass B

Glass C

Sample

θ

Detected light (%)

100

10

1

0.1

0.01

0.001

Angle of direction of detection (θ)10 20 30 40 50 60 70 80 900

Fluorescence Spectrophotometer for Solar Applications

Solar cell modules using silicon crystals, which are currently in the mainstream,

principally use light from the visible to the near-infrared region for power generation.

However, sunlight contains a considerable amount of rays in the UV region, which are

not suitable for power generation. As an approach to circumventing this problem,

efforts are under way to improve the power generation efficiency by converting UV light

into visible light by using fluorescent materials.

The F-7000 is a highly sensitive fluorescence spectrophotometer with the world's top

scanning speed in its class. For the evaluation of the fluorescent characteristics of

materials, the F-7000 rapidly measures both excitation and emission spectra. In

addition, for the assessment of the fluorescence conversion efficiency of a given

fluorescent material, the system can accommodate the measurement of the quantum

yield of fluorescent materials.

Measuring the fluorescent characteristics of fluorescent (photovoltaic) materials

Model F-7000 Fluorescence Spectrophotometer

Excitation/emission spectra of Eu

ConversionExcitation spectrum

(absorbed light)Emission spectrum

(converted light)1,000

0250 750

Flu

ore

sce

nce

in

ten

sity

Wavelength

3D spectra of Eu

500

230550 750

Excita

tio

n w

ave

len

gth

(n

m)

Emission wavelength (nm)

Measurements of the excitation and emission spectra of an Eu fluorescent material used as a UV light conversion material (left figure) clearly indicate that the material

converts UV light near 250 to 400 nm to red light approximately 600 nm in wavelength.

The figure on the right shows a 3D fluorescence spectrum, plotting the excitation wavelength on the vertical axis, the emission wavelength on the horizontal axis, and

the fluorescence intensity in contour lines. Because of its high scan speed (60000 nm/min), which is among the highest in the world, the F-7000 is capable of

high-speed measurement of 3D fluorescence spectra. These spectra can be a powerful aid in the assessment of fluorescence characteristics at various excitation

wavelength, such as for searching for peaks in an excitation or emission wavelength of an unknown sample.

NOTICE: For proper operation, follow the instruction manual when using the instrument.

Specifications in this catalog are subject to change with or without notice, as Hitachi High-Technologies Corporation continues to develop the latest technologies and products for our customers.

Tokyo, Japanhttp://www.hitachi-hitec.com/global/science/24-14 Nishi-Shimbashi 1-chome, Minato-ku, Tokyo, 105-8717, Japan

Tel: +81-3-3504-7211 Fax: +81-3-3504-7123

For further information, please contact your nearest sales representative.

Printed in Japan (H) HTB-E062 2010.1