Light-emitting diode into a lower energy level and releases energy in the form of a photon. The wavelength of the light emitted, and thus its color, depends on the band gap energy of the materials forming the "p-n junction". In silicon or germanium diodes, the electrons and holes usually recombine by a "non-radiative transition", which produces no optical emission, because these are indirect band gap materials. The materials used for the LED have a direct band gap with energies corresponding to near-infrared, visible, or near-ultraviolet light. LED development began with infrared and red devices made with gallium arsenide. Advances in materials science
High-CRI LED lighting High-CRI LED lighting High-CRI LED lighting is a light-emitting diode (LED) lighting source that offers a high color rendering index (CRI). CRI is a quantitative measure of a light's ability to reproduce the colors of objects faithfully in comparison with an ideal or natural light source. In general terms, CRI is a measure of a light source's ability to show object colors "realistically" or "naturally" compared to a familiar reference source, either incandescent light or sunlight. Efficiently achieving an acceptable CRI has been the most difficult metric for light bulbs attempting to replace incandescent bulbs. It is therefore frequently ignored