Ni ions doped oxyflourophosphate glass as a triple ultraviolet–visible–near infrared broad bandpass optical filter

Abstract

Research and development R&D about new materials that can be used as an optical filter, shortpass, bandpass, and longpass is still ongoing. So, in this context, the 50P2O5–20ZnF2–15MgF2–15PbF2 doped different concentrations of NiO ranging from 0 up to 4 mol% as a bandpass filter was prepared using the conventional melt annealing method. The formation of the amorphous essence was observed in the X-ray diffraction patterns. The role of Ni ions in the produced glass network was studied by density and Fourier Transform Infrared FTIR spectroscopy results, which showed that the Ni ions play a network modifier role. Thermal analysis results showed high thermal stability for the produced glasses. Electron paramagnetic resonance EPR spectra results clarified that the Ni3+ ions occupy an elongated octahedral (g⊥> g‖≈ 2). The measurements of AC conductivity, dielectric constant, and electric modulus were studied at different temperatures and frequencies. The ionic conduction dominates the conductivity at high temperatures, while the electronic dominates at low temperatures. The appearance of Ni3+ (confirmed by ESR) and Ni2+ were observed in the optical absorption spectra, also it was found that both of them occupy both tetrahedral and octahedral sites. Three distinguished bands in the UV (centered at 354 nm), visible (centered at 620 nm), and NIR (centered at 1074 nm) regions appeared in the optical transmittance spectra, indicating the defining characteristic of the bandpass filter.