Enhanced photoluminescence, electrochemical and photocatalytic activity of combustion synthesized La10Si6O27:Dy3+ nanophosphors

Abstract

In the present investigation, the wet chemical combustion method was used for the first time to prepare La10Si6O27 phosphors by incorporating Dy3+(1–11 mol %) cations (LNPs). The powder X-ray diffraction patterns of LNPs display the oxyapatite hexagonal phase. The estimated crystallite size, using Scherer's method, is between 20 and 30 nm and the same was confirmed via Transmission Electron Microscopy (TEM). The bandgap energy (Eg) values calculated from diffuse reflection data were in the range of 5.6–5.72 eV. The emission spectrum is composed of characteristic transitions of Dy3+ cations (intra 4f), namely 4F9/2 → 6H15/2 (blue-479 nm), 4F9/2 → 6H13/2 (yellow-578 nm) and 4F9/2 → 6H11/2 (red-670 nm) under near-UV excitation energies. The emission results confirm the choice of using LNPs in applications of white light emitting diodes and the same was found in Color chromaticity coordinates. The white emission intensity was attributed to inherent defects, in particular oxygen vacancies which could contribute to the transfer of energy from the host to dopant ions. The results from current–voltage (CV) and electrochemical impedance spectra (EIS) show the strong electrochemical properties of LNPs. The solution of paracetamol and sildenafil (Penagra) was effectively sensed using modified carbon paste electrodes. LNPs showed a good photocatalytic activity (PCA) for Orange Red (OR) dye under UV light irradiation. These results indicate that the synthesized LNPs are a good candidate for displays, waste water treatment and for the use as electrochemical sensors.

Keywords

• La10Si6O27:Dy3+
• Photoluminescence
• Photocatalytic
• CIE
• EIS
• Sensor