Adjustable emission and energy transfer of BaGdGaO4: Bi3+, Eu3+phosphors with high quantum efficiency for multifunctional applications

A series of Bi3+, Eu3+- activated BaGdGaO4 (BGGO) phosphors were synthesized by the solid-phase reaction. Subsequently, their crystal structure, optical characteristics, and thermal stability were comprehensively investigated. Under ultraviolet excitation, the BGGO: Bi3+ phosphor exhibits a deep blue emission ranging from 350 to 550 nm, with a peak emission at 411 nm and an external quantum efficiency of up to 45 %. Integrating the BGGO: Bi3+ sample with commercially available red and green phosphors achieved a high-quality white light emitting diode (LED) with high general color rendering index (CRI) of 92.7 and low correlated color temperature (CCT) of 2928 K. Additionally, a blue-red dual-emission phosphor was synthesized via the BGGO: Bi3+, Eu3+, which exhibits a high energy transfer efficiency (eta T = 85.4 %) of Bi3+ to Eu3+ and tunable emission properties. The multi-modal anti-counterfeiting capabilities of the synthetic fluorescent powder were further investigated, leading to a multi-color switching model characterized by intuitive visualization and straightforward identification. These results imply that the co-activation of Bi3+ and Eu3+ in BGGO phosphors has significant potential for applications in health lighting, plant lighting, and multimodal anti-counterfeiting.