Dy3+@Mn4+ co-doped Ca14Ga10−mAlmZn6O35 far-red emitting phosphors with high brightness and improved luminescence and energy transfer properties for plant growth LED lights

Abstract

A novel substrate of Ca₁₄Ga_10−mAl_mZn₆O₃₅ (CGAZO) was successfully synthesized via a high-temperature solid-state reaction method and co-doped with Dy³⁺ and Mn⁴⁺ to form a new deep red phosphor (CGAZO:Dy³⁺,Mn⁴⁺) for plant growth LED lighting. This extraordinary phosphor can exhibit strong far-red emission with a maximum peak at 715 nm between 650 and 750 nm, and other four shoulder peaks at 680, 689, 698 and 706 nm, which can be ascribed to 2E_g → 2A_g spin-forbidden transition of Mn⁴⁺. X-ray diffraction (XRD) patterns clarified that Ga³⁺ sites in the host were partly replaced by Al³⁺ ions. Moreover, an effective energy transfer from Dy³⁺ to Mn⁴⁺ in the CGAZO host had been verified since linear reduction of emission intensities and decay times of the Dy³⁺ emission of the phosphors CGAZO:Dy³⁺,Mn⁴⁺ with increasing concentration of Mn⁴⁺ was observed. Finally, a LED device was fabricated using a 460 nm blue-chip, silicon gel, and the as-obtained far-red emitting CGAZO:Dy³⁺,Mn⁴⁺ phosphors. The results of the tobacco plant cultivation lighting by this LED device indicate that the as-prepared phosphor has a potential application in the agricultural industry.