Microstructure, optical, and electrical characteristics of NaBaBi2(PO4)3: Sm3+ orange-red phosphor for WLEDs

Abstract

White light-emitting diodes (WLEDs) are widely used as lighting devices in daily life. However, due to the scarcity of orange-red components, they lack warm white light. Therefore, there is an urgent need for orange-red phosphors to improve the lighting quality and generate more saturated and warm white light. In this regard, NaBaBi2(PO4)3: xSm3+ orange-red phosphors were synthesized using the solid-state method. A systematic study was conducted on the microstructure, optical, and electrical properties of NaBaBi2(PO4)3: xSm3+ phosphors through various characterizations such as X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, fluorescence decay curves, and electrochemical impedance spectroscopy. The diffuse reflectance spectrum indicates that with the increase of Sm3+ doping concentration, the optical bandgap decreases. Remarkably, the NaBaBi2(PO4)3: 0.05Sm3+ phosphor has good thermal stability, and its retention rate is 84.42% at a high temperature of 428 K. Furthermore, the packaged LED manifested desirable characteristics, such as a low correlated color temperature (CCT ∼ 4280 K) and a high color rendering index (CRI ∼ 82), as evidenced by rigorous testing. These results indicate that the NaBaBi2(PO4)3: Sm3+ phosphors have a significant potential for utilization in the LED lighting industry.