Enhancing Luminescence and X-ray Absorption Capacity of Eu³⁺:LaF₃ Nanoparticles by Bi³⁺ Codoping

Abstract

Bi3+ codoping has been proposed in this work with a twofold objective, namely, enhancing the luminescence emission of Eu3+:LaF3 nanoparticles (NPs) and increasing their X-ray attenuation capacity, with the purpose of obtaining a bimodal bioprobe for luminescence bioimaging and X-ray computed tomography. The synthesis method, reported here for the first time for LaF3 particles, allowed obtaining uniform, nonaggregated NPs using a homogeneous precipitation in polyol medium at room temperature in just 2 h. The simplicity of the synthesis method allows the large-scale production of NPs. LaF3 NPs with different Eu3+ contents were first synthesized to find the critical Eu3+ concentration, producing the highest emission intensity. This concentration was subsequently used to fabricate Bi3+–Eu3+-codoped LaF3 NPs using the same method. The emission intensity of the codoped NPs increased in more than one order of magnitude, thanks to the possibility of excitation through the Bi3+ → Eu3+ energy-transfer band. The luminescence properties of the codoped NPs were analyzed in detail to find the mechanism responsible for the emission enhancement. Finally, it was demonstrated that the high atomic number of Bi3+, higher than that of lanthanides, was an added value of the material because it increased its X-ray attenuation capacity. In summary, the LaF3 NPs codoped with Eu3+ and Bi3+ presented in this work are promising candidates as a bimodal bioprobe for luminescence bioimaging and X-ray computed tomography.

Multimodal Luminescent Yb3+/Er3+/Bi3+‐Doped Perovskite Single Crystals for X‐ray Detection and Anti‐Counterfeiting

“…A small amount of Bi 3+ doped into RE‐1 structure absorbs the high energy from X‐ray, which enhances the structure perfection, promotes the exciton localization, and further improves the XEL performance as well as the photoluminescence quantum yield (PLQY). [ 17,28,36,55 ]…”

Dysprosium and Holmium Vanadate Nanoprobes as High-Performance Contrast Agents for High-Field Magnetic Resonance and Computed Tomography Imaging

“…More interestingly, the slope of the obtained straight line for our systems was very similar (29.6 HU/mg cm –3 for DyVO 4 and 29.1 HU/mg cm –3 for HoVO 4 ) and much higher than that for iohexol (12.7 HU/mg cm –3 ), an iodine-based probe, indicating that a lower dose of our Dy- or Ho-based CA is required to obtain a similar contrast, which should be favorable for the patient. The higher X-ray attenuation capacity of our CAs when compared with iohexol can be attributed to the higher atomic number of Dy ( Z = 66) and Ho ( Z = 67), as compared with that of I ( Z = 53), since it is well-known that the X-ray attenuation coefficient increases with the fourth power of Z . The similar Z value for Dy and Ho therefore justifies the similar X-ray attenuation properties of the Dy- and Ho-based samples.…”

“…The higher X-ray attenuation capacity of our CAs when compared with iohexol can be attributed to the higher atomic number of Dy (Z = 66) and Ho (Z = 67), as compared with that of I (Z = 53), since it is wellknown that the X-ray attenuation coefficient increases with the fourth power of Z. 25 The similar Z value for Dy and Ho therefore justifies the similar X-ray attenuation properties of the Dy-and Ho-based samples. Magnetic properties.…”

Tunable luminescence from Bi3+ sensitized La2Zr2O7:Eu3+ red nanophosphors for display applications

“…The observed decrease in emission intensities above 3 at% concentration of Eu 3+ in the codoped sample is accounted for by the concentration quenching effect and is a sign of the existence of energy transfer between Bi 3+ to Eu 3+ . [ 52,53 ] The existence of energy transfer phenomena is demonstrated by the spectral overlap graph between emission spectra of La 2 Zr 2 O 7 :0.5 at% Bi 3+ and excitation spectra of La 2 Zr 2 O 7 :3 at% Eu 3+ which is depicted as Figure 6d. It was observed that, the emission pattern of Bi 3+ in host overlap with the excitation spectra of Eu 3+ strongly confirms the efficient energy transfer between Bi 3+ and Eu 3+ in the host lattice (Figure 6d).…”