Wavelength, often denoted as λ (lambda), measures the distance between two consecutive wave peaks. In the context of solar panels, we are primarily concerned with the range of wavelengths within the solar spectrum. Ultraviolet light has shorter wavelengths, typically below 400 nm. Visible light falls within the range of approximately 400 to 700 nm.
The more photons that hit the solar panel, the more electricity is produced. The spectrum of sunlight ranges from about 380 nm (violet light) to about 750 nm (red light). Solar panels are designed to absorb sunlight in a specific range of wavelengths. This range is known as the solar panel's "band-gap."
This detailed article will delve into the intricacies of solar panel spectral absorbance, wavelengths, and the various factors that can impact their performance. Solar panels absorb light from various parts of the solar spectrum, including ultraviolet, visible, and infrared light, with different wavelengths impacting their efficiency.
Silicon solar cells are efficient at absorbing these shorter wavelengths. Longer wavelengths, including infrared, carry lower energy photons and are less efficiently absorbed by silicon solar cells. Let’s delve into the physics behind it to understand solar cells’ spectral absorbance better.
When photons, particles of light, strike the solar cell, they can be absorbed if their energy matches or exceeds the band gap energy. Shorter wavelengths, such as UV and blue light, carry higher energy photons. Silicon solar cells are efficient at absorbing these shorter wavelengths.
In the context of solar panels, we are primarily concerned with the range of wavelengths within the solar spectrum. Ultraviolet light has shorter wavelengths, typically below 400 nm. Visible light falls within the range of approximately 400 to 700 nm. Infrared light has longer wavelengths beyond 700 nm.