Non-Rare-Earth Na3AlF6:Cr3+ Phosphors for Far-Red Light Emitting Diodes

Emerging phototherapy in a clinic and plant photomorphogenesis call for efficient red/far-red light resources to target and/or actuate the interaction of light and living organisms. Rare-earth-doped phosphors are generally promising candidates for efficient light-emitting diodes but still bear lower quantum yield for the far-red components, potential supply risks, and high-cost issues. Thus, the design and preparation of efficient non-rare-earth activated phosphors becomes extremely important and arouses great interest. Fabrication of Cr3+-doped Na3AlF6 phosphors significantly promotes the potential applications by efficiently converting blue excitation light of a commercial InGaN chip to far-red broadband emission in the 640–850 nm region. The action response of phototherapy (∼667–683 nm; ∼750–772 nm) and that of photomorphogenesis (∼700–760 nm) are well overlapped. Based on the temperature-dependent steady luminescence and time-resolved spectroscopies, energy transfer models are rationally established b...