Al3+ doping enhanced photoluminescence properties of Ca2InNbO6: Mn4+ far-red phosphor for plant cultivation

The study focuses on the synthesis of far-red phosphors Ca2InNbO6: xMn4+ (0 ≤ x ≤ 0.006) and Ca2InNbO6: 0.003Mn4+, yAl3+ (0 ≤ y ≤ 0.024). First-principles calculations confirmed that the indirect bandgap of Ca2InNbO6 used to be 3.522 eV. Photoluminescence spectroscopy was used to examine the luminescence characteristics and energy transfer mechanism of CINO: xMn4+ and CINO: 0.003Mn4+, yAl3+ phosphors. When Mn4+ ions undergo the 2Eg → 4A2g transition under 380 nm excitation, brilliant red light with a central wavelength of 688 nm is released. In addition, the emission intensity reaches 2.6 times that of CINO: 0.003Mn4+, when Al3+ has a 1.2% optimal doping concentration. At the same time, the thermal stability of the material is improved. The reasons for the enhanced fluorescence and thermal stability were analysed by lattice distortion and blocking of energy transfer. Additionally, the prepared red LED lamps, which shown a bright red light even after long periods of operation at high temperatures, were used for the cultivation of plant seeds, and the germination rate as well as the stems and leaves thriving growth were significantly better than the cultivation without the red LED, suggesting that Al3+ doping Ca2InNbO6: Mn4+ has potential applications in the field of plant cultivation and growth LEDs, and is a guide for ion-doped modified phosphors.