Solar spectral distribution curve, solar radiation spectral distribution curve, Solar Radiation Spectrum

Air mass refers to the distance that light travels in the atmosphere. 1 Air Mass， Or AM1, refers to the thickness of the Earth's atmosphere. AM0 refers to the solar radiation in outer space that is not affected by the atmosphere. The power density of AM1.5 is approximately 1000W/m2, and the power density of AM0 is approximately 1360W/m2, which are defined as the solar constant.

For photovoltaic testing (ground applications), the standard testing conditions are defined as an intensity of 1000W/m2 (1 SUN) at 25 ℃, with a solar constant of 1000W/m2, and a solar spectral distribution equivalent to AM1.5G. A standard for spectral radiation distribution has been established for the classification of solar simulation systems.

Solar spectrum

The total solar radiation on the Earth's surface is reduced by up to 45% compared to outer space within a given area and time, mainly due to reflection and absorption. About half of the solar radiation reaching the Earth's surface is located in the visible part of electromagnetic waves. Nevertheless, the potential of solar energy is enormous. The total amount of solar energy reaching the Earth's surface each year exceeds the total energy consumption by approximately 10000 times.

The majority of losses in photovoltaic solar cells (over 50%) are related to spectral matching (the bandgap of energy absorbed by semiconductor materials cannot span the entire solar spectrum). The key to the radiation of the solar simulation system lies in matching, as closely as possible to the spectral distribution of solar radiation on the Earth's surface.