Monday, December 19, 2011

Scientists managed to create the first solar cell with a quantum efficiency greater than 100%

Scientists from the National Renewable Energy Laboratory (NREL) managed to create the first solar cell with a quantum efficiency of more than 100%.
Quantum efficiency is the ratio of the number of electrons that have arisen in the chain of the solar cell to the number of photons of a certain wavelength, incident on the surface per unit time. Given that a high-energy photon could "knock out" a few electrons, the quantum efficiency can exceed 100%.
NREL specialists managed to get 114% rate. For an item that works on radiation impinging in the solar spectrum, a value obtained for the first time.
The key to success, according to scientists, was the use of multi-exciton generation effect, in which one absorbed photon creates a single pair of "electron-hole." Such a mechanism is particularly effective in the so-called "quantum dots" - nanocrystals of the semiconductor, which begin to appear essentially quantum effects.


Scientists managed to create the first solar cell with a quantum efficiency greater than 100%
In a record efficiency solar cell using materials such as zinc oxide and lead selenide (precisely because it was to form "quantum dots"). The researchers hope that their development in the future will lead to solar panels that produce electricity that could cost competitive with electricity from other sources.
Source: NREL