Lanthanide–Organic Framework Nanothermometers Prepared by Spray‐Drying

Abstract

Accurate, noninvasive, and self-referenced temperature measurements at the submicrometer scale are of great interest, prompted by the ever-growing demands in the fi elds of nanotechnology and nanomedicine. The thermal dependence of the phosphor's luminescence provides high detection sensitivity and spatial resolution with short acquisition times in, e.g., biological fl uids, strong electromagnetic fi elds, and fast-moving objects. Here, it is shown that nanoparticles of [(Tb 0.914 Eu 0.086 ) 2 (PDA) 3 (H 2 O)]·2H 2 O (PDA = 1,4-phenylenediacetic acid), the fi rst lanthanide-organic framework prepared by the spray-drying method, are excellent nanothermometers operating in the solid state in the 10-325 K range (quantum yield of 0.25 at 370 nm, at room temperature). Intriguingly, this system is the most sensitive cryogenic nanothermometer reported so far, combining high sensitivity (up to 5.96 ± 0.04% K −1 at 25 K), reproducibility (in excess of 99%), and low-temperature uncertainty (0.02 K at 25 K).

Optical Properties of Hybrid Organic‐Inorganic Materials and their Applications

“…[127][128][129][130] Although relatively recent (luminescent thermometry exploded over the past five years), the technique appears to be beneficial to many technological applications in a great variety of areas, such as microelectronics, microfluidics, bio-and nanomedicine. [131] Examples of luminescent thermometers based on organic-inorganic hybrids include metal-organic molecular compounds, [132] layer double hydroxides, [133] metalorganic frameworks, [134] polymer nanocomposites, [135] QDs in polymers, [136] inorganic NPs coated with an organic (or hybrid) layer, [137] and di-ureasil films co-doped with Eu 3+ and Tb 3+ $-diketonate complexes. [119,138] These later films were used as self-referenced and efficient luminescent probes to map temperature in microelectronic circuits [119,138,139] and optoelectronic devices, [140] demonstrating an intriguing application of hybrid materials in microelectronics.…”

Elaboration of Luminescent and Magnetic Hybrid Networks Based on Lanthanide Ions and Imidazolium Dicarboxylate Salts: Influence of the Synthesis Conditions

“…The value of the χT product at 300 K is the expected value for the isolated Sm 3+ ion (S = 5/2, g J = 2/7) [44]. At 52 K, the value of the χT product is equal to 0.09 emu·K·mol −1 , which is the theoretical value for the Sm 3+ ion in its ground state, 6 H 5/2 [45]. The value at 1.8 K is smaller, suggesting the presence of weak antiferromagnetic interactions between Sm 3+ ions [33].…”

“…The three spectra show a common band centered at 220 nm due to the intraligand π-π* transition of the imidazolium ligand [26,31,38] Figure 11. The excitation spectra (monitored for λ em = 404 nm) show seven peaks corresponding to the transitions from the ground state of the Sm 3+ ion, 6 Figure 12. The spectra show a broad band between 400 nm and 550 nm with a maximum at 433 nm, which is attributed to the luminescence of the imidazolium ligand [31].…”

“…The versatility of the synthesis of such metal coordination polymers is now exploited to generate new functional hybrid networks with specific electronic properties (luminescence, magnetism, conductivity, etc.) [6][7][8][9][10].…”

Rare earth based nanostructured materials: synthesis, functionalization, properties and bioimaging and biosensing applications

“…Spray-based methods have also been reported in the literature. Figure 1I) [66]. Other examples are mechanochemical syntheses, which imply the mechanical breakage of intramolecular bonds, which is followed by a chemical transformation.…”