Temperature-Sensitive Chameleon Luminescent Films Based on PMMA Doped with Europium(III) and Terbium(III) Anisometric Complexes

The spin-coating technique was used to produce composite films consisting of PMMA polymer doped with anisometric complexes of Eu(III) and Tb(III). It was found that an increase in the content of Tb3+ complexes intensifies emission of both ions due to the intermolecular energy transfer from the Tb(III) complex to the Eu(III) complex, which results in the increase in the relative luminescence quantum yield of Eu(III) ion by 36%. The temperature sensitivity of the film luminescence intensity and lifetime in the range of 296–363 K was investigated. The maximum relative sensitivity of the films reaches 5.44% × K−1 and exceeds that of all known lanthanide-containing thermal sensors designed for measuring physiological temperatures. In combination with changing luminescence color, such a sensitivity makes these films promising colorimetric thermal sensors for in situ temperature measurements.

Synthesis and luminescence properties of Eu3+-activated BiF3 nanoparticles for optical thermometry and fluorescence imaging in rice root

The luminescence, optical thermometric properties, phytotoxicity, and fluorescence imaging in plant cells of Eu³⁺-activated BiF₃ nanoparticles were systematically studied. Under the excitation of near-ultraviolet light, the prepared compounds emitted visible red light arising from the intra-4f transitions of Eu³⁺ ions. By employing the fluorescence intensity ratio technique, the temperature sensing performance of the synthesized nanoparticles was investigated and the maximum sensitivity was demonstrated to be 3.4 × 10⁻⁵ K⁻¹ at 443 K. Furthermore, the rice root, which was treated with Eu³⁺-activated BiF₃ nanoparticles, showed similar primary root elongation and crown root number to the seedlings cultivated in the MS0 medium without nanoparticles, indicating the relatively low phytotoxicity of the resultant samples to the rice root. Additionally, the results of the toxicity-related gene levels and phenotypes also demonstrated the low phytotoxicity of the as-prepared nanoparticles to the plant cells. Ultimately, with the help of the red emission of Eu³⁺ ions, the studied compounds were found to be accumulated in the division and differentiation regions of the rice root rather than transferred to the above-ground tissues. These results suggest that the Eu³⁺-activated BiF₃ nanoparticles may have potential applications in non-invasive optical temperature sensors and fluorescence probes in plant cells.

The luminescence, optical thermometric properties, phytotoxicity, and fluorescence imaging in plant cells of Eu³⁺-activated BiF₃ nanoparticles were systematically studied.

Luminescent properties of Eu3+-activated Gd2ZnTiO6 double perovskite red-emitting phosphors for white light-emitting diodes and field emission displays

We synthesized a series of double perovskite Eu³⁺-activated Gd₂ZnTiO₆ red-emitting phosphors by a solid-state reaction method and analyzed their morphology, crystallinity, luminescent properties, and thermal stability.

A stoichiometric terbium-europium dyad molecular thermometer: energy transfer properties

The optical thermometer has shown great promise for use in the fields of aeronautical engineering, environmental monitoring and medical diagnosis. Self-referencing lanthanide thermo-probes distinguish themselves because of their accuracy, calibration, photostability, and temporal dimension of signal. However, the use of conventional lanthanide-doped materials is limited by their poor reproducibility, random distance between energy transfer pairs and interference by energy migration, thereby restricting their utility. Herein, a strategy for synthesizing hetero-dinuclear complexes that comprise chemically similar lanthanides is introduced in which a pair of thermosensitive dinuclear complexes, cycTb-phEu and cycEu-phTb, were synthesized. Their structures were geometrically optimized with an internuclear distance of approximately 10.6Å. The sensitive linear temperature-dependent luminescent intensity ratios of europium and terbium emission over a wide temperature range (50-298K and 10-200K, respectively) and their temporal dimension responses indicate that both dinuclear complexes can act as excellent self-referencing thermometers. The energy transfer from Tb³⁺ to Eu³⁺ is thermally activated, with the most important pathway involving the ⁷F₁ Eu³⁺ J-multiplet at room temperature. The energy transfer from the antenna to Eu³⁺ was simulated, and it was found that the most important ligand contributions to the rate come from transfers to the Eu³⁺ upper states rather than direct ligand-metal transfer to ⁵D₁ or ⁵D₀. As the first molecular-based thermometer with clear validation of the metal ratio and a fixed distance between the metal pairs, these dinuclear complexes can be used as new materials for temperature sensing and can provide a new platform for understanding the energy transfer between lanthanide ions.

Luminescence and energy transfer in a color tunable CaY4(SiO4)3O:Ce3+, Mn2+, Tb3+ phosphor for application in white LEDs

White light with CIE coordinate (0.3553, 0.3338) was generated in the sample.