Sensitized intense near-infrared downconversion quantum cutting three-photon luminescence phenomena of the Tm(3+) ion activator in Tm(3+)Bi(3+):YNbO(4) powder phosphor

Dual-emitting temperature dependent material based on Bi3+/Eu3+ co-activated Ba2Y2Si4O13 phosphor with multicolor anti-counterfeiting

Bi³⁺, Eu³⁺ co-doped Ba₂Y₂Si₄O₁₃ phosphors with multi-color luminescence properties were prepared by high temperature solid state method. The structure, luminescent properties and temperature characteristics were studied by X-ray diffraction, scanning electron microscope, fluorescence spectrum and temperature-dependence of emission spectrum. Ba₂Y₂Si₄O₁₃: Bi³⁺, Eu³⁺ phosphors can emit color from cyan to red when the excitation wavelength was changed from 340 nm to 390 nm, which is attributed to that there are two Bi³⁺ ion emission centers, and their emission intensity will change with the change of excitation wavelength. Moreover, the emission of the phosphor has good temperature sensing characteristics, based on the fluorescence intensity ratio of the two blue emission bands of Bi³⁺ and the red emission peak of Eu³⁺, a multimode thermometer with high temperature sensitivity was constructed. At the same time, based on the dynamic luminescence characteristics of the phosphor, the dynamic anti-counterfeiting experiments are designed. Therefore, the results show that the material has a bright prospect in the field of temperature sensing and anti-counterfeiting.

Luminescence Spectroscopy and Origin of Luminescence Centers in Bi-Doped Materials

Bi-doped compounds recently became the subject of an extensive research due to their possible applications as scintillator and phosphor materials. The oxides co-doped with Bi3+ and trivalent rare-earth ions were proposed as prospective phosphors for white light-emitting diodes and quantum cutting down-converting materials applicable for enhancement of silicon solar cells. Luminescence characteristics of different Bi3+-doped materials were found to be strongly different and ascribed to electronic transitions from the excited levels of a Bi3+ ion to its ground state, charge-transfer transitions, Bi3+ dimers or clusters, radiative decay of Bi3+-related localized or trapped excitons, etc. In this review, we compare the characteristics of the Bi3+-related luminescence in various compounds; discuss the possible origin of the corresponding luminescence centers as well as the processes resulting in their luminescence; consider the phenomenological models proposed to describe the excited-state dynamics of the Bi3+-related centers and determine the structure and parameters of their relaxed excited states; address an influence of different interactions (e.g., spin-orbit, electron-phonon, hyperfine) as well as the Bi3+ ion charge and volume compensating defects on the luminescence characteristics. The Bi-related luminescence arising from lower charge states (namely, Bi2+, Bi+, Bi0) is also reviewed.

Spectral and energy transfer in Bi3+–Ren+ (n = 2, 3, 4) co-doped phosphors: extended optical applications

Bismuth with [Xe]4f¹⁴5d¹⁰6s²6p³ electronic configuration is considered as ‘a wonder metal’ due to its diverse oxidation states and multi-type electronic structures.