Solar Simulator
Class AAA small area solar simulator at an affordable price
Reliable LED light source for small area solar cell testing
The Ossila Solar Simulator is a compact, low price light source suitable for characterising small area solar cells. Using a powerful LED lamp, the solar simulator has an AAA classification over a 15 mm diameter circular area and an ABA classification over a 25 mm diameter area (IEC 60904-9:2020 International Standard). Combine with our automated or manual solar cell I-V test systems (available as a bundle deal with the solar simulator) to equip your laboratory with a fully integrated solar cell characterisation system. Just plug it in, turn it on, and start measuring. The LED lamp supplies a stable output and requires zero maintenance and virtually no warm-up time.
What is a solar simulator?
Testing and characterisating the operating parameters of materials or solar cells requires solar illumination. It is often impractical to test devices under the actual sun because of the inconsistency in solar radiation which occurs due to changeable weather and the day-night cycle. Comparing devices tested in different locations would also be challenging if you used the actual sun, as atmospheric effects mean that the intensity of solar radiation varies over the Earth's surface. Solar simulators are light sources designed to alleviate these issues by supplying a reliable and controllable approximation of solar radiation relative to a standardised spectrum.
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Key Features
LED lamp
The Ossila Solar Simulator uses light-emitting diodes to generate its light output. The advantages of LEDs over arc-lamp or incandescent alternatives include:
- High efficiency
- Long operating lifetime
- High temporal stability
- Zero maintenance
- Spectral tunability
- Virtually zero warm-up time
- Ozone-free
Modular design
You can purchase the Ossila Solar Simulator as a stand-alone head unit for custom mounting, as a height adjustable system for use with your existing test setup or packaged with our manual/automated Solar Cell IV Test System for a complete measurement solution.
Programmable
The Ossila Solar Simulator needs no special programming or set up. For most applications, all you need to do to get started is turn it on. However, for more complex systems that require custom configurations, you can use a serial command library to individually set the illuminance of each LED within the lamp, or the total irradiance. This gives you complete control of the system.
Compact
We have designed our solar simulator for environments with limited space. Whether that be high density laboratories, or inside a glove box*, the Ossila Solar Simulator can fit into the smallest of spaces.
* Not for use in volatile environments.
High specification
The Ossila Solar Simulator is AAA rated for small area devices, including our 20mm x 15mm, and class ABA for larger devices such as our 25mm x 25mm substrate systems. We individually calibrate each system is with a NIST traceable photo radiometer and include a performance report with each unit. Click on the image below to download a sample report.
Classification
There are several different recognised standards for classifying solar simulators, each of which is published by a different standards organisation (IEC, ATSM, or JIS). Although there are slight differences between the standards, they all classify solar simulators based upon their performance in three key areas. These areas are:
- Spectral match to a standardised solar spectrum
- Spatial non-uniformity
- Temporal instability
Solar simulators receive a grade A to C in each of these areas. The better the performance, the higher the rating. The latest IEC 60904-9:2020 standard, and the one which we follow, also allows for an A+ classification in each field.
Spectral match to a standardised solar spectrum
The light emitted by the Sun has spectral power distribution that is approximately that of a black body at 5800K. Because some wavelengths of light are more strongly absorbed by molecules in the Earth than others, the light arriving at the surface appears as a black body curve with some wavelength bands of lower intensity. The intensity of the light will also depend on how much atmosphere the light passes through.
The most common standardised spectrum is the AM1.5 spectrum, which approximates sunlight received at middle latitudes. The AM1.5 spectrum is divided into wavelength bins containing a known percentage of the total solar irradiance.
To determine the classification rating of a solar simulator, the measured irradiance from the lamp is compared with the standard spectrum for each wavelength bin. The more closely they match, the higher the rating.
The absolute spectral irradiance of the Ossila Solar Simulator at 8.5 cm can be seen in the graph below for a total integrated power of 100 mW/cm2 (1 sun) over the wavelength range 350 nm - 1000 nm.
Spatial non-uniformity
Due to the large distance between the Sun and the Earth, rays emitted from the Sun are approximately parallel at the Earth's surface. This creates a very uniform spatial distribution of energy. Solar simulators emulate this uniformity, often using optical elements such as lenses, mirrors, and diffusers.
A more uniform distribution of light from a solar simulator better approximates light from the Sun. The intensity of light from a solar simulator is mapped over a plane, and more uniform illumination is assigned a higher classification.
The irradiance profile of the Ossila Solar Simulator is circular. At the working distance of 8.5 cm and output power of 1 sun, it achieves a spatial non-uniformity class A rating over a 15 mm diameter, a class B rating over 25 mm diameter, and a class C rating at 32 mm diameter.
Temporal instability
The intensity of the light output from a solar simulator can vary over time due to factors including power supply variations or the age of the lamp. The former would affect stability over short timescales (the time taken to record successive points in an I-V dataset) while the latter would affect longer timescales and would be of importance for measurements such as solar cell aging or slow I-V sweeps.
Both short-term and long-term instability may be assessed in the classification of solar simulators, but for many solar simulators, only long-term instability is needed. Lower instabilities (smaller peak-to-peak intensity variations) result in higher classifications.
The long-term temporal instability of the Ossila Solar Simulator is shown above, achieving a class A rating.
Applications
Solar cell characterisation
The most obvious use of a solar simulator is in characterising photovoltaic devices. The solar cell is illuminated under a solar simulator, and a current-voltage sweep is performed. Knowing the properties of the light and measuring the electrical properties of the cell, the device efficiency can be calculated. Measuring how the device efficiency degrades over time under operating conditions is also an important measurement, this is known as lifetime testing. The Ossila Solar Simulator can be used as a standalone system for integration into existing test platform or installed onto our solar cell I-V test system for a complete testing package.
Materials testing
Many materials need to withstand extended periods under sunlight, for example structural or aesthetic plastics that can become brittle or discoloured under prolonged ultraviolet light exposure. Other materials need to effectively absorb solar radiation, such as packaging materials to protect their contents, or sunscreen to protect skin. A solar simulator allows repeatable, quantitive measurements of a materials response to solar irradiation.
Photobiology
The study of the effects of light on living organisms is called photobiology. The most important source of light on Earth is the Sun as it drives photosynthesis in plants and circadian rhythms in both plants and animals. Lab-based studies of these processes may require a more controllable substitute for the Sun. A solar simulator is an ideal alternative.
Resources and Support
All specifications are subject to change before the launch of the Ossila Solar Simulator.
Technical Specifications
| Type | LED-Based, Steady-State |
| Spectral deviation | <70% |
| Spectral coverage | >80% |
| Working distance (cm) | 8.5 cm |
| Irradiance (at working distance) | 1000 W/m2 |
| Dimensions (head only) L x W x H |
10.5 cm x 9.0 cm x 8.0 cm |
| Weight | 600 g |
| Spectral match | A |
| Spatial uniformity over 15 mm diameter area | A |
| Spatial uniformity over 25 mm diameter area | B |
| Spatial uniformity over 32 mm diameter area | C |
| Temporal instability | A |
Spectral Irradiance
The absolute spectral irradiance at 8.5 cm from system is shown in the figure below, for a total integrated power of 100 mW/cm2 (1 sun) over the wavelength range 350 nm - 1000 nm.
Spatial non-uniformity
The irradiance profile of the Ossila Solar Simulator is circular. At the working distance of 8.5cm and output power of 1 sun, it achieves a spatial non-uniformity class A rating over a 15 mm diameter, a class B rating over 25 mm diameter and a class C rating 32 mm diameter.
Temporal instability
The long-term temporal instability of the Ossila Solar Simulator is shown below, achieving a class A rating.
Find the answers to some commonly asked questions below. For any other queries, please contact us.
General
How does the Ossila Solar Simulator compare to higher price systems?
We have designed our system to be as affordable as possible to make it accessible to as many researchers as possible. While our system will fulfill the needs of many researchers, there are some situations where our system would not be suitable. These include:
- An active device area which extends beyond a 25 mm diameter circle.
- Cells with prominent absorption features between ~750 nm - 850 nm.
- Where an intensity of over 1 sun is required (this can be achieved at shorter working distances, but the illumination uniformity is not guaranteed).
Why am I measuring different device efficiencies between different solar simulators?
The measured device metrics depend upon the spectral irradiance of the light source and the spectral responsivity of the device. All solar simulators will provide a different spectral irradiance, and this difference can be large when comparing arc lamp to LED type solar simulators. A parameter called 'spectral mismatch' can be used to correct for this deviation. We have a guide on spectral mismatch here. The Ossila Solar Simulator allows the user to set the total irradiance, as well as control each of the 11 LEDs independently, giving you complete control over your measurement.
Specifications
How can we check the calibration of the Ossila Solar Simulator?
Coming Soon - Our calibrated solar irradiance meter will at-a-glance report the irradiance at the detector in units of suns. The emission wavelengths can be measured with a spectrometer.
What do the classification letters mean?
Spectral match
The solar spectrum can be divided into wavelength bins, each containing a certain percentage of the total solar irradiance. These bins and the corresponding irradiance percentage as specified by the IEC 60904-9:2020 standard is given below.
| Bin | Wavelength range (nm) | % of total solar irradiance |
| 1 | 300 - 470 | 16.61 |
| 2 | 470 - 561 | 16.74 |
| 3 | 561 - 657 | 16.67 |
| 4 | 657 - 772 | 16.63 |
| 5 | 772 - 919 | 16.66 |
| 6 | 919 - 1200 | 16.69 |
The ratio of the percentage of solar irradiance and measured solar simulator irradiance is calculated for each bin, and the ratio with the largest deviation from unit is used to determine the solar simulator class as defined by the table below.
| Classification | Ratio of irradiance percentage for all bins |
| A+ | 0.875 - 1.125 |
| A | 0.75 - 1.25 |
| B | 0.6 - 1.4 |
| C | 0.4 - 2.0 |
Spatial non-uniformity
The integrated irradiance of the solar simulator is mapped as a function of position in the measurement plane of the device according to a procedure outline in the relevant standard. The spatial non-uniformity is then calculated using:
Spatial non-uniformity equation
The classification is then assigned according to the table below.
| Classification | Spatial non-uniformity (%) |
| A+ | 1 |
| A | 2 |
| B | 5 |
| C | 10 |
Temporal instability
The integrated irradiance of the solar simulator is recorded at regular intervals over a period outlined in the relevant standard. The temporal instability is then calculated using:
Temporal instability equation
The classification is then assigned according to the table below.
| Classification | Short-term instability | Long-term instability |
| A+ | ≤0.25% | ≤1% |
| A | ≤0.5% | ≤2% |
| B | ≤2% | ≤5% |
| C | ≤10% | ≤10% |
Related Products
Compatible Substrates and Fabrication Equipment
To the best of our knowledge the information provided here is accurate. However, Ossila assume no liability for the accuracy of this page. The values provided are typical at the time of manufacture and may vary over time and from batch to batch. All products are for laboratory and research and development use only, and may not be used for any other purpose including health care, pharmaceuticals, cosmetics, food or commercial applications.