Site Substitution Triggered Luminescence Characteristics Modulation in Eu³⁺‐Activated Sr₄La₆(SiO₄)₆Cl₂ Phosphors for Boosting Viral Resistance and Plant Growth

Abstract

A series of Eu³⁺‐activated Sr₄La₆(SiO₄)₆Cl₂ (SLSCl) phosphors are prepared to fulfill the requirements of plant growth and immunity. Upon 394 nm excitation, the resulting phosphors can emit intense red emission from Eu³⁺, of which their intensities are sensitive to dopant content and site occupation. When Eu³⁺ occupies La³⁺ and Sr²⁺ sites, its optimal doping contents in SLSCl host lattices is 40 and 50 mol%, respectively. Moreover, the quantum efficiency and thermal stability of designed phosphors are also greatly dependent on the site taken by Eu³⁺ in SLSCl host lattices. Via utilizing the designed phosphors as red‐emitting converters, two different light‐emitting diodes (LEDs) are fabricated, whose emission bands overlap with the absorption bands of plant pigments, enabling their feasibilities in plant growth. Furthermore, the plant growth experiments indicate that the photosynthesis can be significantly improved via employing the packaged LEDs as supplementary lights. Additionally, the packaged red‐emitting LEDs can enhance the resistance of the N. benthamiana plants against viral infection. The findings do not only propose a facile route to manipulate the luminescence properties of Eu³⁺‐activated phosphors, but also confirm that the utilization of red light as supplementary light is an efficient to promote plant growth and viral resistance.