Luminescence properties and energy transfer mechanism of La2ZnTiO6:Mn4+/Er3+ far-red/green dual-emitting phosphors for plant lighting

Abstract A new far-red/green dual-emitting phosphor La2ZnTiO6:Mn4+/Er3+ (LZT:Mn4+/Er3+) was successfully synthesized by the sol-gel method. Under 381 ​nm excitation, LZT:Mn4+/Er3+ phosphor shows the strong far-red emission peak of 709 ​nm (Mn4+: 2Eg→4A2g) and weak green emission peak of 523/548 ​nm (Er3+: 2H11/2/4S3/2 ​→ ​4I15/2), which consistent with the requirement of plant growth for far-red and green light. A 1.5-fold enhancement of far-red emission intensity is found in LZT:Mn4+/Er3+ phosphor compared with the Mn4+ singly-doped counterparts. Moreover, the relative emission intensity of far-red and green can be easily controlled by changing temperature. Utilizing the optimal LZT:0.2%Mn4+/2%Er3+ phosphor as plant lighting, a prototype near-UV-pumped LED device was fabricated. Upon 120 ​mA driving current, it demonstrated far-red/green dual emission. All the results indicated that the LZT:Mn4+/Er3+ phosphor is a potential material for plant growth illumination with far-red/green light.