Energy transfer properties of CaYAlO4:Bi3+, Mn4+ phosphor for indoor crop cultivation LED lighting

This paper reports a series of Bi3+/Mn4+ doped CaYAlO4 (CYAO:Bi3+, Mn4+) phosphors prepared via sol-gel method. The phase purity and accurate crystal structure information of these phosphors were confirmed by the measurement of XRD, TEM and Reitveld refinement. Under excitation of 346 nm, CYAO:Bi3+, Mn4+ phosphors show two broad emission bands centered at 407 nm and 709 nm, respectively. The results of PL spectra and decay lifetime measurement prove that the energy transfer from Bi3+ to Mn4+ in CYAO host can be realized. The emitting intensity of CYAO:0.01Bi3+, 0.005Mn4+ phosphor can be enhanced by 184% than Bi3+-free sample and its energy-transfer efficiency and internal quantum efficiency (IQE) reach up to 85% and 54% respectively. With the introduction of Bi3+, the activation energy of CYAO:0.01Bi3+, 0.005Mn4+ can be improved from 0.31eV to 0.44eV as compared with CYAO:0.005Mn4+ phosphor, indicating that its thermal stability performance has a great enhancement. Furthermore, the CIE value and the luminous efficiency the fabricated pc-LED device are (0.7211, 0.2788) and 0.6 l m/W. Meanwhile, its emission spectrum matches well with the absorption spectrum of PFR, which implies that this phosphor can be a potential candidate for application in indoor crop cultivation.