At G2V Optics, we receive many questions on various topics surrounding solar simulation. We have created an FAQ section to help the scientific community learn about solar simulation and solar simulators. If your question isn’t found here, contact us; we are happy to get you an answer!
Frequently Asked Questions (FAQ) about Solar Simulation
Can we use a lamp as a light source instead of a standard solar simulator?
Not if you want reliable, reproducible measurements. A lamp (of any type) will give irradiation that, without filters, will not reproduce the sun spectrum. Additionally, if you do not have a stable power supply, you will experience variations in irradiance intensity over time. If you need to conduct experiments requiring a light source that closely mimics the sun, use a solar simulator. Below is an example of a B2 LED light bulb vs a Solar simulator output overlayed on the AM1.5G standard (the terrestrial standard). You can note the variations in how close the spectrum matches.
Is there a problem in measuring solar cell efficiency using a white light source instead of a solar simulator?
Yes. A light source that has not been designed and calibrated to mimic the sunlight spectrum will not give you an accurate measurement of solar cell performance. In order to be able to compare your solar cell measurements to other solar cells you need to have a light source that provides you with the standard spectrum. See above image.
What is a spectral mismatch in a solar simulation?
It measures the amount of light produced within specific wavelength bands compared to the standard spectra. This is the margin error around the expected value for those more versed in statistics. Spectral mismatch can theoretically range from 0% to 80+ %; the lower the value, the better.
Will there be UV in the light produced by an AM1.5G solar simulator?
It depends on the lighting technology. Under the Class AAA designation, ultraviolet light between 300 nm and 400 nm is not specified. Xenon bulbs will produce a small amount of UV, whereas LED solar simulators can omit it entirely. Depending on your setup you may just require additional irradiance to meet closer to the expected mW/cm2 value and be less concerned with the type of photon coming in. We can help you with this.
What is AM1.5G Spectrum?
The Air Mass (AM1.5) spectrum is a standard at mid-latitudes that is used by experts in the field as the go-to for testing and comparing. Check out our AM1.5 chapter for more information.
Is there a need for any special environmental requirements like temperature or humidity control or a clean room to operate a solar simulator?
No, you do not need a special environment unless your specific research requires it (for example, a glove box or climate chambers). In most lab settings, ambient temperature (<30C) and humidity are acceptable. If you do have a glovebox or climate application, a few questions you will want to have answers to are:
- Atmospheric conditions- nitrogen, argon, helium etc.
- Dimension inside of the glove box- We recommend leaving a 5-10 cm buffer away from the walls and top to accommodate for airflow and moving the solar simulator if required.
- Environment- The humidity and temperature at which the chamber will operate.
Can solar simulators be used for microbial cultures?
Yes, you can use a solar simulator to conduct any research that needs a light source that mimics the sun. A benefit of higher-end LED solar simulators for microbial research is their ability to tune the spectrum. This will give you control over the light your cultures may see, such as low light in a cave or specific wavelengths of interest.
How do you best choose a solar simulator?
Whether you need a pulsed or a steady-state simulator, solar simulators should be chosen according to your needs (see our Solar Simulator pricing article for a list of criteria). Note that at the bottom of the article, we have included a second download of a pricing matrix to help you compare it against solar simulators. We are always happy to assist you in evaluating instruments.
What’s the difference between Spectra and Spectrum?
The short answer is that “spectra” is the plural form of “spectrum.”
The word spectrum originates from the latin word for “image” or “apparition.” Because of its latin origin, the plural of spectrum is “spectra.”
However, as all languages morph over time, and since spectrum as a word has been adopted into the English language, the use of “spectrums” as a plural form has gradually become more common and widely accepted.
How hot will my samples get?
Depending on your solar simulator, this can vary dramatically. With xenon solar simulators, they produce substantially further into the IR range, where the heating effect comes from. You can purchase additional filters to shield the IR and compensate for this. These filters may affect the solar simulators’ spectral match and spatial uniformity. We have found that the sample can reach 30C-35C from ambient ~22C for LED solar simulators due to the low heat LED produces.
Another option we have seen users opt for is a cooling stage or “jacket” for their substrate. This usually has a liquid circulated on the surface to remove the heat from the object on top.
How do quartz/ceramic/other substrate windows affect solar simulators?
There will be a loss experience due to Fresnel reflection and per optical surface (front and back). The more surfaces placed together, the more loss. Our solar simulators can accommodate these losses through tuning. Having the manufacturer’s data or a sample for testing are two of the best ways to ensure quality can be met.
Why is a solar simulator output < 1000W/M2 or 100 mW/cm2?
This is because solar simulators do not cover the entire solar spectrum but only target a range of it. For an in-depth explanation and examples, check out our Solar Simulator Spectral Irradiance Article.
