Synthesis and photoluminescence properties of Ca2LaTaO6:Mn4+ phosphor for plant growth LEDs

The double perovskite-type structure Ca2LaTaO6:Mn4+ phosphor is synthesized successfully by solid-state reaction method in air. X-ray powder diffractions (XRD) patterns, energy dispersive X-ray (EDX) spectrum, morphology, luminescence properties, decay curves, temperature-dependent emission spectra, and time-resolved emission spectra of Ca2LaTaO6:Mn4+ phosphor are investigated. Ca2LaTaO6:Mn4+ phosphor shows deep red emission with the emission band peaking at 696 nm in the range of 600-800 nm due to the E-2 -> (4)A(2) transition of Mn4+ ion. The optimal Mn4+ concentration in Ca2LaTaO6:Mn4+ phosphor is similar to 0.4 mol%. Lifetime decreases from 0.721 to 0.555 ms with increasing Mn4+ concentration in the range of 0.1-1.0 mol%. The concentration quenching mechanism is dominated by a dipole-dipole interaction. The activation energy is determined to be 0.3203 eV. The luminous mechanism and temperature quenching are explained by the Tanabe-Sugano energy level diagram and configuration coordinate diagram of Mn4+ ion, respectively. The red emitting light-emitting diode (LED) device is fabricated by using the Ca2LaTaO6:Mn4+ phosphor. The experimental results indicate that Ca2LaTaO6:Mn4+ phosphor has a potential applications in LEDs for plant growth. (C) 2018 Elsevier B.V. All rights reserved.