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
LED printer variety of materials including glass, plastic, plexiglass, etc. UV LED printers are often used in the promotional products industry to print on pens, usb drives and mugs. Current models of commercial LED UV Printers like the Compress iUV600s and iUV1200s are also capable of adding texture to a print. LED printer An LED printer is a type of computer printer similar to a laser printer. LED technology uses a light-emitting diode array as a light source in the printhead instead of the laser used in laser printers and, more generally, in the xerography process. The LED bar pulse-flashes across the