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The value of the photosynthetic efficiency is dependent on how light energy is defined – it depends on whether we count only the light that is absorbed, and on what kind of light is used (see Photosynthetically active radiation). It takes eight (or perhaps ten or more [1]) photons to use one molecule of CO 2.
Biological tissues typically produce an observed radiant emittance in the visible and ultraviolet frequencies ranging from 10 −17 to 10 −23 W/cm 2 (approx 1-1000 photons/cm 2 /second). [1] This low level of light has a much weaker intensity than the visible light produced by bioluminescence, but biophotons are detectable above the ...
Solar cell efficiencies vary from 6% for amorphous silicon-based solar cells to 44.0% with multiple-junction production cells and 44.4% with multiple dies assembled into a hybrid package. [ 23 ] [ 24 ] Solar cell energy conversion efficiencies for commercially available multicrystalline Si solar cells are around 14–19%. [ 25 ]
The first demonstration of the photovoltaic effect, by Edmond Becquerel in 1839, used an electrochemical cell. He explained his discovery in Comptes rendus de l'Académie des sciences, "the production of an electric current when two plates of platinum or gold immersed in an acid, neutral, or alkaline solution are exposed in an uneven way to solar radiation."
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect. [1] It is a form of photoelectric cell, a device whose electrical characteristics (such as current , voltage , or resistance ) vary when it is exposed to light.
In 1905, Albert Einstein published a paper advancing the hypothesis that light energy is carried in discrete quantized packets to explain experimental data from the photoelectric effect. Einstein theorized that the energy in each quantum of light was equal to the frequency of light multiplied by a constant, later called the Planck constant. A ...
[8] [9] Macro-architecture of the solar cells could result in different surface areas being placed in any fixed volume - particularly for thin film solar cells and flexible solar cells which may allow for highly convoluted folded structures. If volume is the binding constraint, then efficiency density based on surface area may be of less relevance.
In a typical solar cell, the photovoltaic effect is used to generate electricity from sunlight. The light-absorbing or "active layer" of the solar cell is typically a semiconducting material, meaning that there is a gap in its energy spectrum between the valence band of localized electrons around host ions and the conduction band of higher-energy electrons which are free to move throughout the ...