Modular high power plant lighting sources based on phosphor–sapphire composites with high thermal conductivity

Abstract

It is very crucial to select appropriate plant lighting sources to supplement light for plants according to their different requirements for light during different growth periods. However, LED-driven plant lighting sources confront the challenges of long-term operation stability and modular light color switching requirements. Herein, red emitting, far-red emitting, and patterned multi-color emitting phosphor–sapphire composite (PSC) samples were fabricated by co-sintering CaAlSiN₃:Eu²⁺/Gd_2.4Lu_0.6Ga₄AlO₁₂:Cr³⁺ and low-melting glass powder on sapphire plates. The phase, microstructure, and luminescent properties of these PSC specimens were systematically investigated. Notably, after 34 days of continuous operation, the luminescence intensity of the fabricated high power plant lighting LED device can maintain 93% of its initial integrated intensity, benefitting from robust resistance to light irradiation and thermal shock. Moreover, the emitting color of these modular high power LED devices can be easily switched by using different PSC samples depending on the light color need of the plants. All these results indicate that the PSC samples reported in this paper have merits of easy fabrication, low cost and long-lifetimes, showing promising applications in the field of plant growth lighting.