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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 type of photoelectric cell, a device whose electrical characteristics (such as current , voltage , or resistance ) vary when it is exposed to light.
The process of water-splitting is a highly endothermic process (ΔH > 0). Water splitting occurs naturally in photosynthesis when the energy of four photons is absorbed and converted into chemical energy through a complex biochemical pathway (Dolai's or Kok's S-state diagrams). [3] O–H bond homolysis in water requires energy of 6.5 - 6.9 eV ...
The theory of solar cells explains the process by which light energy in photons is converted into electric current when the photons strike a suitable semiconductor device. The theoretical studies are of practical use because they predict the fundamental limits of a solar cell , and give guidance on the phenomena that contribute to losses and ...
Active solar techniques include the use of photovoltaic systems, concentrated solar power, and solar water heating to harness the energy. Passive solar techniques include designing a building for better daylighting , selecting materials with favorable thermal mass or light-dispersing properties, and organizing spaces that naturally circulate air .
Photoelectrolytic cell band diagram. A (water-splitting) photoelectrolytic cell electrolizes water into hydrogen and oxygen gas by irradiating the anode with electromagnetic radiation, that is, with light. This has been referred to as artificial photosynthesis and has been suggested as a way of storing solar energy in hydrogen for use as fuel. [1]
In a solar photoelectrochemical process, hydrogen can be produced by electrolysis. To use sunlight in this process, a photoelectrochemical cell can be used, where one photosensitized electrode converts light into an electric current that is then used for water splitting. One such type of cell is the dye-sensitized solar cell. [10]
The process can be categorized based on the type of solar energy source utilized. In direct solar desalination, saline water absorbs solar energy and evaporates, leaving behind salt and other impurities. An example of this is solar stills, where an enclosed environment allows for the collection and condensation of pure water vapor.
Photosynthetic cells use the sun's energy to split off water's hydrogen from oxygen. [107] In the presence of sunlight, hydrogen is combined with CO 2 (absorbed from air or water) to form glucose and release oxygen. [108] All living cells use such fuels and oxidize the hydrogen and carbon to capture the sun's energy and reform water and CO