Investigating photoluminescence properties of Eu3+ doped CaWO4 nanoparticles via Bi3+ amalgamation for w-LEDs application

Eu3+-doped CaWO4 nanophosphors were synthesised in series for different atomic wt% concentrations (0, 0.5, 1, 2, 5 and 10) of Bi3+ by polyol method. Their structure and morphology were characterised using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photoluminescence properties and energy transfer from Bi3+ to Eu3+ in CaWO4:Eu3+/Bi3+ nanophosphors were also investigated. The results revealed that red luminescence of CaWO4:2Eu(3+)/1Bi(3+) nanophosphor is 5.4 times stronger than CaWO4:2Eu(3+). It was observed that the forces exist between Bi3+ and Eu3+ are due to the interaction of electric dipole-dipole interactions. The chroma of CaWO4:2Eu(3+)/1Bi(3+) nanophosphors was calculated to be 97.40%. The energy transfer process was studied by measuring the decay curves due to Bi3+ and Eu3+ dopants. Enhanced red emission, high thermal stability, stronger D-5(0) -> F-7(2) absorption intensity, high colour purity and decay studies indicate that CaWO4:Eu3+/Bi3+ nanophosphors are potential candidates to be used in white light-emitting diode (wLEDs).