CHARACTERIZATION AND SPECTROSCOPY OF A SOLID-STATE SYNTHESIZED ER³⁺-DOPED CAYW PHOSPHOR FOR OPTOELECTRONICS

Abstract

In this study, Calcium Yttrium Tungstate (Ca₃Y₂WO₉) (CaYW) phosphors doped with Er3+ ions were synthesized using the conventional solid-state reaction technique. An undoped host matrix CaYW was fabricated at three different temperatures—1100°C, 1200°C, and 1250°C—while varying the sintering duration between 10 and 12 hours. The prepared samples were further studied using the X-ray diffraction (XRD) technique, revealing that diffraction peaks of the sample sintered at 1100°C closely matched the standard JCPDS pattern (card number 00-038-0218). Furthermore, the material was identified as having a tetragonal crystal structure. Based on these findings, 1100°C was determined to be the optimal sintering temperature, with an ideal sintering time of 10 hours and 40 minutes. Following this, a series of CaYW:xEr3+ phosphors was synthesized with varying Er3+ doping concentrations. The concentrations that were taken into calculations were 1 mol%, 3 mol%, 5 mol%, 7 mol% and 9 mol% of Er3+. Their photoluminescence (PL) properties were examined along with the correlated colour temperature(CCT) and colour purity(CP) , revealing strong luminescence in the green spectrum of the visible light region, with a peak centred at 563 nm when excited at 380 nm. However, concentration quenching was noted when Er3+ doping level exceeded 7 mol%. Consequently, 7 mol% was identified as the optimal doping concentration, and this sample was selected for further characterization techniques such as XRD, scanning electron microscope(SEM), ultra violet(UV) spectroscopy along with diffuse reflectance spectra(DRS), fourier transformed infrared(FTIR)spectroscopy and thermogravimetric analyses(TGA) along with differential Thermal Analyses (DTA) . Overall, the key insights of this research suggest that Er3+- doped CaYW phosphors demonstrate promising potential for usage in white light-emitting diode (w-LED) applications.