植物工廠可以在任何季節、任何地區產出無農藥以及無蟲害的新鮮蔬菜和水果,而逐漸引起廣大的重視;然而,現有的光源當中,如高壓鈉燈、白熾燈泡、螢光燈管和發光二極體,其所提供的光譜,皆與植物的吸收光譜,明顯地不匹配,這是因為植物的吸收光譜,在可見光的短、中、長區域,具有三個寬而非窄的吸收帶;因此,我們利用一個擬多寬帶光譜的固態照明技術,設計、製作植物成長光源。以有機發光二極體(Organic light emitting diode, OLED)為例,所得OLED元件之光譜,與光合作用光譜,有84%的相似性,而此乃緣自使用一個放光範圍,涵蓋短至中波長區域的雙波峰藍光染料,再搭配一個放光範圍,涵蓋中至長波長區域之波幅寬廣的單波峰紅光染料。若再摻雜一深紅光染料時,此一OLED植物成長光源的光合作用光譜相似性,可以再提升至90%。以一般的發光二極體(light emitting diode, LED)而言,若使用三個窄帶以取代原本單一窄帶的藍光,並額外加入兩個窄帶的紅光,則所得光合作用光譜相似性,也可提升至91%。此一擬多寬帶光譜技術,不僅可以使所提供的能量,被植物更完全的吸收利用,也可以用以設計一個更佳的光源,以符合各種不同的植物,在長根、莖、葉、果時之不同光源需求。
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.