Yellow-to-orange emission from B2+-doped RF2 (R = Ca and Sr) phosphors

The riddle of orange-red luminescence in Bismuth-doped silica glasses

For over the past two decades it has been believed that the intense orange-red photoluminescence in Bismuth-doped materials originates from Bi[Formula: see text] ions. Based on the results from magnetic circular polarization experiments, we demonstrate that this hypothesis fails for Bismuth-doped silica glasses. Our findings contradict the generally accepted statement that the orange-red luminescence arises from [Formula: see text] [Formula: see text] [Formula: see text] transition in a divalent Bismuth ion. The degree of magnetic circular polarization of this luminescence exhibits non-monotonic temperature and field dependencies, as well as sign reversal. This complex behaviour cannot be explained under the assumption of a single Bi[Formula: see text] ion. The detailed analysis enables us to construct a consistent diagram of energy levels involved in the magneto-optical experiments and propose a new interpretation of the nature of orange-red luminescence in Bismuth-doped silica glass. A centre responsible for this notorious photoluminescence must be an even-electron system with an integer total spin, presumably a dimer of Bismuth ions or a complex consisting of Bi[Formula: see text] and an oxygen vacancy.

Preparation of zero-thermal-quenching tunable emission bismuth-containing phosphors through the topochemical design of ligand configuration

We report a high performance bismuth-containing phosphor with zero-thermal-quenching, which can be used for white light illumination and non-contact temperature sensing.

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.

Surface Sensitive Techniques for Advanced Characterization of Luminescent Materials

The important role of surface sensitive characterization techniques such as Auger electron spectroscopy (AES), X-ray photo electron spectroscopy (XPS), time of flight scanning ion mass spectrometry (TOF-SIMS) and High resolution transmission electron microscopy (HRTEM) for the characterization of different phosphor materials is discussed in this short review by giving selective examples from previous obtained results. AES is used to monitor surface reactions during electron bombardment and also to determine the elemental composition of the surfaces of the materials, while XPS and TOF-SIMS are used for determining the surface chemical composition and valence state of the dopants. The role of XPS to determine the presence of defects in the phosphor matrix is also stated with the different examples. The role of HRTEM in combination with Energy dispersive spectroscopy (EDS) for nanoparticle characterization is also pointed out.

Ultra-broadband luminescent from a Bi doped CaO matrix

CaO:Bi phosphor powders were successfully synthesized by the sol–gel combustion method. Both blue and orange emission were obtained with CL excitation, Bi²⁺ in the BiO clusters was responsible to the orange emission under electron beam excitation.

Blue absorption and red emission of Bi2+ in solids: strongly spin–orbit coupled 6p levels in low symmetry fields

Ab initio calculations on a (BiO₈)¹⁴⁻ cluster under the effects of a high symmetry O_h confinement potential are used to study the energies of the ²P_1/2, ²P_3/2(1), and ²P_3/2(2) spin–orbit coupling levels of the 6s²6p configuration of Bi²⁺ in O_h, D_4h, D_2h, D₄, D_2d, D₂, S₄, C_4v, C₄, C_3v, C_2v, C₂, C_s, and C₁ fields, together with the ²P_1/2 → ²P_3/2(1) and ²P_1/2 → ²P_3/2(2) absorption oscillator strengths and the ²P_3/2(1) radiative lifetime.