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Alkaline zirconium fluorides (AxZryFx+y, A = Li, Na, and K), featuring unique crystallographic structures, have recently emerged as a class of attractive hosts for fabricating lanthanide (Ln3+)‐doped upconversion nanocrystals (UCNCs) that exhibited distinct morphology, upconversion luminescence (UCL) performance, and physicochemical property. In this paper, for the first time the controlled preparation of Yb3+/Er3+‐doped UCNCs is reported based on the trigonal Cs2ZrF6 host, leading to tunable morphology and size of the resulting UCNCs by varying the reaction temperature and time. By further incorporating Na+ ions into the Cs2ZrF6 crystal lattice, sub‐10 nm Yb3+/Er3+/Na+ tridoped UCNCs with highly improved crystallinity and thus greatly enhanced UCL intensity are obtained. Moreover, these resulting UCNCs display abnormal thermal enhancement of UCL over a temperature range from 333 to 493 K, enabling the fabrication of supersensitive luminescent nanothermometers for temperature sensing. Based on the luminescence intensity ratio of two nonthermally coupled levels (i.e., 4F9/2 and 2H11/2) of Er3+, the as‐prepared Cs2ZrF6:Yb/Er/Na UCNCs exhibit an extremely large absolute sensitivity of 177.3% K−1 and a considerably high relative sensitivity of 1.52% K−1 at 333 K. These results unambiguously demonstrate that Cs2ZrF6 is a suitable host material for preparing small‐sized Ln3+‐doped UCNCs as nanothermometer for high‐performance ratiometric temperature sensing. [ABSTRACT FROM AUTHOR]

To be successfully implemented, an efficient conversion, affordable operation and high values of CO2‐derived products by electrochemical conversion of CO2 are yet to be addressed. Inspired by the natural CaO‐CaCO3 cycle, we herein introduce CaO into electrolysis of SnO2 in affordable molten CaCl2‐NaCl to establish an in situ capture and conversion of CO2. In situ capture of anodic CO2 from graphite anode by the added CaO generates CaCO3. The consequent co‐electrolysis of SnO2 and CaCO3 confines Sn in carbon nanotube (Sn@CNT) in cathode and increases current efficiency of O2 evolution in graphite anode to 71.9 %. The intermediated CaC2 is verified as the nuclei to direct a self‐template generation of CNT, ensuring a CO2‐CNT current efficiency and energy efficiency of 85.1 % and 44.8 %, respectively. The Sn@CNT integrates confined responses of Sn cores to external electrochemical or thermal stimuli with robust CNT sheaths, resulting in excellent Li storage performance and intriguing application as nanothermometer. The versatility of the molten salt electrolysis of CO2 in Ca‐based molten salts for template‐free generation of advanced carbon materials is evidenced by the successful generation of pure CNT, Zn@CNT and Fe@CNT. [ABSTRACT FROM AUTHOR]

Nanothermometers that can reflect temperature in real‐time are crucial for photothermal therapy. Near‐infrared (NIR) fluorescent probes that conform to Boltzmann distribution will play an important role if they have the above characteristics. Here, the LiLuF4: Nd3+/Yb3+ nanocrystals were designed and synthesized by control, exhibiting multiple bright near‐infrared emission peaks at 925–1080 nm region at 280–360 K under the excitation of an 808 nm laser. The feasibility of being used as a nanothermometer was confirmed by testing the spectral variation with temperature and analysis. [ABSTRACT FROM AUTHOR]

The thermal behavior of enzymes in nanoscale is of great significance to life phenomena. This nonequilibrium state real‐time thermal behavior of enzymes at nanoscale cannot be accurately detected by existing methods. Herein, a novel method is developed for the detection of this thermal behavior. The enzyme‐quantum dot (QD) conjugates can be obtained by chemically grafting temperature‐sensitive amino‐AgInS2 QDs to the enzyme, where the QDs act as nanothermometers with a sensitivity of −2.82% °C−1. Detecting the photoluminescence intensity changes of the enzyme‐QD conjugates, the real‐time thermal behavior of enzymes can be obtained. The enzyme‐QD conjugates show a temperature difference as high as 6 °C above ambient temperature in nano‐microregions with good reproducibility (maximum error of 4%) during catalysis, while solution temperature hardly changed. This method has a temperature resolution of ≈0.5 °C with a detection limit of 0.02 mg mL−1 of enzyme, and spatially ensured that the amino‐AgInS2 QDs are quantitatively bound to the enzyme; thus, it can accurately detect the exothermic behavior of the enzyme and can be extended to other organisms' detection. This method has high sensitivity, good stability, and reliability, indicating its great potential application in investigating the thermal behavior of organisms in nanoscale and related life phenomena. [ABSTRACT FROM AUTHOR]

Temperature measurement in biology and medical diagnostics is of great importance. Herein, a novel carbon nanodot (CND) based fluorescent nanothermometry device for spatially resolved temperature measurements is demonstrated. The fluorescence CNDs are prepared by a simple one-pot solvothermal method using sucrose as carbon source. Resultant CNDs show stable green fluorescence at 520 nm with high quantum yield (≈6%). The fluorescence of resultant CNDs exhibits a reversible linear response to temperature in a wide range of 20-85 °C. Moreover, the temperature resolution better than 0.5 °C and high sensitive variation of ≈1.3% °C−1 are observed in a broad physiological temperature range of 20-40 °C. Therefore, the as-prepared CNDs possess high water solubility, stable fluorescence, small size, and good biocompatibility, which make them promising candidate for thermometry and cell imaging in biological media. [ABSTRACT FROM AUTHOR]