Luminescent Papers with Asymmetric Complexes of Eu(III) and Tb(III) in Polymeric Matrices and Suggested Combinations for Color Tuning

Multi-functional GdEuxTb1-xO3 (x = 0 to 1) nanoparticles: colour tuning optical properties, water proton spin relaxivities, and X-ray attenuation properties

Multi-functional nanoparticles are useful for various applications, such as biomedical imaging, detection, and display technologies. Colour-tunable GdEuxTb1-xO3 nanoparticles were synthesized with emission colour ranging from green (545 nm) to red (616 nm) by varying x (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1). These nanoparticles were surface-grafted with polyacrylic acid and a small quantity of 2,6-pyridinedicarboxylic acid. This modification aimed to ensure long-term colloidal stability (>1 year without precipitation) and high quantum yields (>30%) in aqueous media. Additionally, they exhibited long emission lifetimes (∼1 ms), high longitudinal water proton spin relaxivities (>30 s-1mM-1), and high X-ray attenuation efficiencies (∼10 HU mM-1). These multiple exceptional properties within a single nanoparticle make them highly valuable for applications in biomedical imaging, noise-free signal detection, and colour display.

Luminescence of Binary-Doped Silica Aerogel Powders: A Two-Step Sol-Gel Approach

In this study, we report a novel synthesis of hydrophobic silica aerogel powder composites, functionalized and binary-doped with [Tb(phen)2](NO3)3 and [Eu(phen)2](NO3)3 nanocrystals, employing a two-step sol-gel methodology. The investigation delves into the structural elucidation, optical properties and thermal conductivity of these functionalized Tb(III)-Eu(III) composites. Our analysis includes diffuse reflectance spectra and excitation and luminescence spectra, highlighting the quantum yields of composites with varying chemical compositions. Remarkably, these samples exhibit a strong luminescence, with distinct hues of red or green based on the specific doping type and level. The detailed examination of excitation spectra and quantum yields establishes robust energy-transfer mechanisms from the 1,10-phenanthroline molecule to the lanthanide ions. Notably, our study uncovers a Tb3⁺→Eu3⁺ energy-transfer phenomenon within the binary functionalized samples, providing compelling evidence for a structural formation process occurring within the mesoporous framework of the aerogel powders.