What is quantum efficiency?
Following Rose’s (1946) pioneering work, Horace Barlow provided a clear answer to this question a quarter of a century ago (Barlow, 1962) by defining quantum efficiency as: Barlow stressed the importance of adhering to a strict definition of what is meant by the overall quantum efficiency of visual performance (Barlow, 1977). The emphasis is appropriate because his equation is more than a mere definition, it is a way of thinking about how real visual detectors behave: Now imagine a human subject and an ideal device performing the same task: with no filter in front of it, the ideal device will of course perform better, but by interposing the appropriate filter its performance can be reduced until it matches that achieved by the subject. The fraction of light transmitted by this filter is then equal to the overall quantum efficiency, F, as defined above. (Barlow, 1962; pp. 155-6). Barlow’s idea was a major step forward for at least three reasons. First, it emphasized the importance of id
Quantum efficiency is a ratio of the number of photons at a specific wavelength absorbed by a photovoltaic device compared to the total number incident upon the device. Note that the term is used analogously in astronomy to quantify generic photodetectors. For the measurement a monochromatic light light source is used. The result is not a single number, as in the case of standard AM1.5 efficiency, but a 2D graph of efficiency versus wavelength of the light source. A knowledge of the band gap of a semiconductor and the quantum efficiency graph can be used to optimize operating characteristics. See also: • What does this TLA (Three Letter Acronym) mean? • What is the electromagnetic spectrum? • [Amazon] Basic Photovoltaic Principles and Methods: Solar Energy Research Institute by Kenneth Zweibel, Paul Hersch 10D) What is the recombination factor? When a sufficiently energetic photon has been absorbed by a semiconductor, and an electron-electron hole pair created, sometimes the pair inadv
