Synthesis and spectroscopic analysis of Ba₃Ca₂(PO₄)₃F: Eu³⁺/Tb³⁺ fluorapatite structured phosphor for optical...

Singly and co-doped Eu³⁺ and Tb³⁺ Ba₃Ca₂(PO₄)₃F phosphors were prepared using two-step solid-state reaction (SSR) method. Structure and phase-purity were confirmed using powder X-ray diffraction (PXRD) which confirmed that the synthesized samples formed in fluorapatite structure Also, the morphological analysis and elemental mapping were carried out using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX) which confirms particles were formed inhomogeneous and different sizes. However, EDAX confirmed the presence of Ba, Ca, P, O, and F in desired ratio. The photoluminescence properties were studied using steady-state photoluminescence and emission decay time measurements. The prominent emission for Ba₃Ca₂(PO₄)₃F: Eu³⁺ was at 619 nm corresponding to ⁵D₀ → ⁷F_2,3 transition which is an electronic dipole transition. Along with this, magnetic dipole transition peak at 593 nm also observed which corresponds to ⁵D₀ → ⁷F₂ transition. All emission spectra were measured for excitation wavelength of 393 nm attributes to ⁷F₀ → ⁵L₆ transition. The estimated asymmetric ratio vales suggested a presence of symmetrical host matrix around Eu³⁺ ions. The emission for Ba₃Ca₂(PO₄)₃F: Tb³⁺ covered blue, green and red region. Also, the excitation spectrum showed charge transfer transitions due to [PO₄]^3- as well due Tb³⁺ excitation form ⁷F₆ to D and G energy levels. Likewise, the emission spectra for dual-doped Ba₃Ca₂(PO₄)₃F: Eu³⁺/Tb³⁺ were measured for 230 nm excitation wavelength which covered green and blue emission region as for Tb³⁺ ions and red emission as for Eu³⁺ ions. Moreover, the concentration quenching was observed for all synthesized three series which was due to the dipole-quadrupole interactions. Furthermore, a comparative CIE analysis confirmed the white light emission for Ba₃Ca₂(PO₄)₃F: Eu³⁺/Tb³⁺ inorganic phosphor. In last, time decay characteristics were interpreted in details and the estimated quantum efficiency value was 61.65 %.