Structural, optical behavior and Judd-Ofelt analysis of europium-doped silicophosphate glasses for red-emitting device applications

Silicophosphate glasses doped with europium are of great interest in fundamental fields such as photonics, luminous diodes, optoelectronics, and lasers. In the present study, we have focused on exploring the effect of the europium (Eu3+) dopant on the structural, physical, and optical properties of silicophosphate glasses. In this study, pure and europium-doped silicophosphate glasses were synthesized by using the sol-gel method. To evaluate the structural and optical properties of the prepared glasses, X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV–visible spectroscopy, photoluminescence spectra, and luminescence decay of trivalent europium ions in glasses were examined. XRD revealed that all of the synthesized glasses contained amorphous phases. FTIR transmittance spectra demonstrated that the addition of europium in the silicophosphate glass leads to a reduction in the dimensionality of the network as a result of the rupture of the Si–O–Si bonds into their structure. The band gap energy of the samples increases with the dopant of europium. The photoluminescence spectrum shows the line characteristics of the Eu (III) ion 5D0→7FJ (J = 0, 1, 2, 3 and 4). Large bands were observed, suggesting non-homogeneous sites that are characteristics of amorphous systems. The intensity parameters ΩJ (J = 2, 4) and the radiative properties of Eu3+ ions in the prepared glasses, such as the stimulated emission cross-section (σe), transition probability (A), radiative lifetime (τcal), and branching ratio (βR) were determined, and Eu3+ emission may be suggested for suitable laser applications due to its high value of βR=52.71%. Furthermore, the CIE 1931 color coordinates of the synthesized glass (x, y) are within the range of (0.63, 0.36) and are quite close to the standard red color (0.67, 0.33), indicating that pure bright red emission has been achieved. The obtained results show that the europium-doped silicophosphate glasses can be appropriate for use as a red laser material.