Luminescence properties of a novel promising red phosphor Na3Gd2−x(BO3)3:xEu3+

•A new promising red-emitting Na3Gd2(BO3)3:Eu3+ phosphor was synthesized.•The microstructure and properties of the phosphor were researched in detail.•The phosphor can exhibit pure red light under near-UV excitation.•The quantum efficiency of Na3Gd2(BO3)3:Eu3+ phosphor is as high as 35.2%.

The novel red-emitting Na3Gd2−x(BO3)3:xEu3+ phosphors were synthesized by a solid-state method. Under near ultraviolet excitation, the phosphors exhibit dominant emission peak at 614 nm and generate bright red light, which is attributed to the electric-dipole transition 5D0→7F2. The optimal doping amount of Eu3+ in Na3Gd2−x(BO3)3:xEu3+ phosphors is x=0.3 for the maximum emission. The exchange interaction between Eu3+ ions is identified to be the main mechanism in the concentration quenching process. The CIE color coordinates of the Na3Gd2−x(BO3)3:xEu3+ phosphors (x=0.650, y=0.350) are close to the NTSC standard values of red. With a relatively high quantum efficiency of 35.2%, Na3Gd2−x(BO3)3:xEu3+ red-emitting phosphor is probably a promising candidate for near ultraviolet-based white LEDs application.