Highly efficient and dual broad emitting light convertor: an option for next-generation plant growth LEDs

Abstract

At present, blue-red composite LED light sources used for plant lighting are mainly composed of blue light and red light; the blue light is provided by gallium nitride LED chips, but the full-width at half-maximum (FWHW) is only approximately 25 nm, while the blue light required by plants for photosynthesis is wider. Focusing on this problem, this work reported that a dual emitting phosphor-in-glass plate (Dual-PiGP) was prepared towards a high power and dual broadband emitter, in which BaMgAl₁₀O₁₇:Eu²⁺ (BAM) and CaAlSiN₃:Eu²⁺ (CASN) provide blue and red emission, respectively. Dual-PiGP exhibited several merits, including a high quantum efficiency of 93.90%, a superior thermal stability (80.1%@150 °C of the peak intensity at 25 °C), and a dual broad spectrum with a full-width at half-maximum (FWHM) of 50 and 106 nm at 446 and 645 nm, respectively. Moreover, a proof-of-concept Dual-PiGP plant lamp for application in indoor plant factories was successfully fabricated with Dual-PiGP and a 385 nm emitting LED chip, yielding blue- (400–500 nm) and red-light (580–780 nm) emission that matches well with the absorption spectrum of chlorophyll. The Dual-PiGP plant lamps were applied indoors to cultivate Italian lettuce, and commercial plant lamps assembled by LED chips were chosen as reference. The cultivation results indicated that the biomass of Italian lettuce was 12.12% greater than those cultivated using commercial plant lamps. Further analysis also certificated that the content of soluble protein and total chlorophyll were also improved. The Dual-PiGP light converter strategy provides an option for next-generation plant growth LEDs.