Bi3+-Activated Na3Ca2TaO6: A Novel Narrow-Band Blue-Emitting Phosphor Towards Backlight Display Applications

Developing efficient and stable narrow-band blue phosphors has always been crucial for advancing LED backlighting technology. In this study, a host of Na3Ca2TaO6 with a strong rigid structure and high cationic site symmetry was selected, while Bi3+ was utilized as the activator. A novel narrow-band blue-emitting phosphor Na3Ca2TaO6:Bi3+ was obtained through high temperature solid phase sintering. The excitation peak of Na3Ca2TaO6:0.005Bi3+ is at 370 nm, which can effectively match the near-ultraviolet chip. Under near-ultraviolet light excitation, the Na3Ca2TaO6:0.005Bi3+ sample exhibits narrow-band blue emission, characterized by a dominant peak at 421 nm and a full width at half maximum of 47 nm. Additionally, Na3Ca2TaO6:Bi3+ demonstrates the color purity of 93.7 %, a quantum efficiency of 56.3 % and thermal stability of 80 %@150 °C. Based on crystal structure data, spectral data, and empirical formulas, it can be inferred that Bi3+ occupies the Na2 and Ca site and forms two luminous centers in Na3Ca2TaO6. When Na3Ca2TaO6:Bi3+ is utilized as the blue light component in WLED devices packaging, an impressive NTSC color gamut of 89.4 % can be achieved. The present study is anticipated to serve as a valuable point of reference for the future advancement of phosphors specifically tailored for backlight display applications.