| 摘要 |
Embodiments of this invention comprise a lighting device, such as an organic light emitting diode ("OLED"), constructed so as to form a microcavity that is resonant with an emission wavelength of the emitter and with the emitting region located at an antinode of the resonant mode of the cavity. With the emitting region at this location, this resonant mode operates in stimulated emission and causes the excited state population to be locked at a small level. Interference effects may contribute to this by suppressing spontaneous emission into this mode when the emitter is at this location. Because losses are proportional to the excited state population, the losses are constant or near constant while current is increased. Further, because some device degradation processes are also driven by excited state populations, this can extend the device lifetime as well. In addition, instead of charge density building rapidly with current or output, in this invention, charge density is proportional to the square root of current. This removes some important limitations on maximum brightness. In one embodiment, electricity is generated from light, which results in very high efficiency, especially when utilizing spherical microcavities with a distribution of sizes dispersed in another material making up the photovoltaic cell. |
