Solar
Cell Efficiency
- Conversion efficiency is greatest for photon energies equal to the bandgap.
- If the photon's energy exceeds the bandgap, the energy difference between the photon's energy and the bandgap
is lost as heat.
- Photons with energies less than the bandgap are not absorbed,
but are transmitted through the semiconductor material.
- Multijunction solar cells consist of layers of semiconductors with decreasing bandgaps. The top layers absorb higher-energy photons, while transmitting lower-energy photons that can then be absorbed by lower layers of the cell.
