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
Toyota Prius Plug-in Hybrid included charging cable connects to the charging port inlet located on the right-rear fender. The charge port location was moved from the front driver-side fender in the demonstration model based on input from the program participants. The battery charger cable weighs just , is in length, and fits in its own compartment in the trunk area. The charge port provides LED (Light Emitting Diode) illumination for convenient night-time charging. A timer allows charging to take place during off-peak hours and can be set for either a start or end time. According to Toyota the Prius plug-in was expected to be