Band Gap Solar Panels

When the band gap energy is met the electron is excited into a free state and can therefore participate in conduction.

Band gap solar panels.

Rest of the photon energy is simply a waste in the solar cell as heat. Photons with energy less than the band gap will not separate electron pairs and simply pass through the solar cell. Photons with more energy than necessary to separate an electron pair do generate an electron and a hole with the balance of their enegy being dissipated in the form of heat. The optical band gap see below determines what portion of the solar spectrum a photovoltaic cell absorbs.

Traditional single junction cells with an optimal band gap for the solar spectrum have a maximum theoretical efficiency of 33 16 the shockley queisser limit. The most popular solar cell material silicon has a less favorable band gap of 1 1 ev resulting in a maximum efficiency of about 32. In the bond model of a semiconductor band gap reduction in the bond energy also reduces the band gap. Band gap energy differs from one material to another.

And the energy of the electron hole pair produced by a photon is equal to the bandgap energy. Actually the energy converted is the energy corresponding to the band gap. Limiting efficiency of solar cells solar cells operate on. A semiconductor will not absorb photons of energy less than the band gap.

In a solar cell the parameter most affected by an increase in temperature is the open circuit voltage. This maximum occurs at a band gap of 1 34 ev. Lower energy is therefore needed to break the bond. The band gap determines how much energy is needed from the sun for conduction as well as how much energy is generated.

The band gap is the minimum amount of energy required for an electron to break free of its bound state. Solar cells with multiple band gap absorber materials improve efficiency by dividing the solar spectrum into smaller bins where the thermodynamic efficiency limit is higher for each bin. So the result is a loss in efficiency. It has been estimated that about 1 1 loss occurs for every 1 c rise in temperature of the cell.