Abstract
Plant factory has attracted increasing attention because it can produce at all weathers fresh fruits and vegetables free from pesticides. However, the emission spectra from the current light sources, including high pressure sodium lamps, incandescent bulbs, fluorescent tubes, and light emitting diodes (LEDs), significantly mismatches with the spectra absorbed by plants. We demonstrate in this communication a concept of using pseudo multiple broad-bands solid-state-lighting technologies to design plant-growth light sources. By taking organic light emitting diode for example, the resulting light source shows an 84% resemblance with the photosynthetic action spectrum as a twin-peaks blue dye, that emits from short- to mid-wavelength regions, and a diffused mono-peak red dye, that emits from mid- to long-wavelength regions, are employed. This organic LED based plant-growth light source can also show a greater than 90% resemblance as an additional deeper red emitter is added. For a typical LED, the spectrum resemblance can be improved to 91% as the original one-narrow-band blue emission is replaced by a three-narrow-bands blue counterpart, and an additional two-narrow-bands red emission is incorporated. The present approach may facilitate either an ultimate use of the energy applied for plant growth and/or the design of a better light source for growing different plants.