What is quantum efficiency?
Quantum efficiency is a measurement of how electrically photosensitive photo capable equipment is. Photoreactive surfaces use energy from incoming photons to create pairs of electron holes in which the energy of the photon increases the energy level of the electron and allows the electron to leave the valence belt where electrons are bound to individual atoms, and enter the conductive band where it can move freely across the material grid. The higher the percentage of photons that produce a few electron holes after hitting the photoreactive surface, the higher its quantum efficiency. Quantum efficiency is an important characteristic of a number of modern technologies, especially photovoltaic solar cells used to produce electricity, as well as photographic film and cartridges. Material configurations differ in the way they absorb and reflect different wavelengths, and this is an important factor in what substances are used in different photocitative devices. The most common material for solar cellsIt is a crystalline silicon, but there are also cells based on other photoreactive substances such as teluride cadmia and copper Indium gallium selenid. The photographic film uses a silver bromide, silver or silver iodide chloride, either alone or in combination.
The highest quantum efficiency is produced by devices associated with chargers used for digital photography and high -resolution display. These devices collect photons with a layer of epitaxial silicon subsidized by a boron, which creates electric charges, which then move by a number of capacitors to the charge amplifier. The charge amplifier converts charges to a series of voltages that can be processed as an analog signal or recorded digitally. The entry associated with a charge that is often used in scientific applications such as astronomy and biology that requires great accuracy and sensitivity may have a quantum efficiency of 90 percent or iníce.
In solar cells, quantum efficiency is sometimes divided into two measurements, external quantum efficiency and internal quantum efficiency. External efficiency is the measurement of the percentage of all photons interference in the solar cell, which produces a few electron openings that are successfully collected by the cell. Quantum efficiency only calculates those photons that hit a cell that have not been reflected or transmitted from the cell. Poor internal efficiency suggests that too many electrons that have been increased to the level of line, lose energy and re -attach to the valence atom, which is a process called recombation. Poor external efficiency can either be a reflection of poor internal efficiency, or it may mean that a large amount of reach of the lighting is not available for use because it is reflected by the cell or leaving it.
As soon as the electrons begin to move into the conductive zone, the design of solar cells controls the direction of their movement to form a flow of direct current. SinceHigher quantum efficiency means that more electrons can enter the conductive band and be successfully collected, higher efficiency allows generate more power. Most solar cells are designed to maximize quantum efficiency in the wavelengths of light most common in the Earth's atmosphere, rated spectrum, although specialized solar cells for the use of infrared or ultraviolet light have also been developed.