Tunable luminescence and energy transfer properties of Bi3+ and Mn4+ co-doped Ca14Al10Zn6O35 phosphors for agricultural applications

Abstract

A series of Bi³⁺ and Mn⁴⁺ co-activated Ca₁₄Al₁₀Zn₆O₃₅ (CAZO) phosphors were synthesized using a solid state sintering method. The phase and morphologies of the CAZO based phosphors were confirmed using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. A novel phosphor CAZO:Bi³⁺ emits bright blue light under near-ultraviolet (NUV) excitation and its luminescence properties were characterized by diffuse reflectance and photoluminescence spectra. Tunable luminescence from blue to red was observed in Bi³⁺ and Mn⁴⁺ co-activated CAZO, which is attributed to energy transfer from Bi³⁺ to Mn⁴⁺. The energy transfer mechanism has been characterized by the decay times of the Bi³⁺ emission, which changes with the concentration of Mn⁴⁺. The energy transfer efficiency from Bi³⁺ to Mn⁴⁺ increases linearly with increasing the concentration of Mn⁴⁺. The as-obtained phosphor has a potential application in agricultural industry because the blue and red lights excited by NUV light emitting diodes (LEDs) are helpful for the improvement of photosynthesis.