Quantum Efficiency
The quantum efficiency (QE), or incident photon to converted electron (IPCE) ratio, of a photosensitive device or a charge-coupled device (CCD) is the percentage of photons hitting the device's photoreactive surface that produce charge carriers. It is measured in electrons per photon or amps per watt. QE is a measurement of a device's electrical sensitivity to light. Since the energy of a photon is inversely proportional to its wavelength, QE is often measured over a range of different wavelengths to characterize a device's efficiency at each photon energy level. The QE for photons with energy below the band gap is zero. Photographic film typically has a QE of much less than 10%, while CCDs can have a QE of well over 90% at some wavelengths.
Read more about Quantum Efficiency: Quantum Efficiency of Solar Cells, Spectral Responsivity
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