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Encapsulation of Dual Emitting Giant Quantum Dots in Silica Nanoparticles for Optical Ratiometric Temperature Nanosensors
摘要： Accurate temperature measurements with a high spatial resolution for application in the biomedical fields demand novel nanosized thermometers with new advanced properties. Here, a water dispersible ratiometric temperature sensor is fabricated by encapsulating in silica nanoparticles, organic capped PbS@CdS@CdS “giant” quantum dots (GQDs), characterized by dual emission in the visible and near infrared spectral range, already assessed as efficient fluorescent nanothermometers. The chemical stability, easy surface functionalization, limited toxicity and transparency of the silica coating represent advantageous features for the realization of a nanoscale heterostructure suitable for temperature sensing. However, the strong dependence of the optical properties on the morphology of the final core–shell nanoparticle requires an accurate control of the encapsulation process. We carried out a systematic investigation of the synthetic conditions to achieve, by the microemulsion method, uniform and single core silica coated GQD (GQD@SiO2) nanoparticles and subsequently recorded temperature-dependent fluorescent spectra in the 281-313 K temperature range, suited for biological systems. The ratiometric response—the ratio between the two integrated PbS and CdS emission bands—is found to monotonically decrease with the temperature, showing a sensitivity comparable to bare GQDs, and thus confirming the effectiveness of the functionalization strategy and the potential of GQD@SiO2 in future biomedical applications.
关键词： silica shell,QD functionalization,nanothermometers,optical sensor,ratiometric sensing
更新于2025-09-23 15:19:57
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Reliability of rare-earth-doped infrared luminescent nanothermometers
摘要： The use of infrared-emitting rare-earth-doped luminescent nanoparticles as nanothermometers has attracted great attention during the last few years. The scientific community has identified rare-earth-doped luminescent nanoparticles as one of the most sensitive and versatile systems for contactless local temperature sensing in a great variety of fields, but especially in nanomedicine. Researchers are nowadays focused on the design and development of multifunctional nanothermometers with new spectral operation ranges, outstanding brightness, and enhanced sensitivities. However, no attention has been paid to the assessment of the actual reliability of the measurements provided by rare-earth-doped luminescent nanothermometers. In fact, it is assumed that they are ideal temperature sensors. Nevertheless, this is far from being true. In this work we demonstrate that the emission spectra of rare-earth-doped nanothermometers can be affected by numerous environmental and experimental factors. These include the numerical aperture of the optical elements used for their optical excitation and luminescence collection, the local concentration of nanothermometers, optical length variations, self-absorption of the luminescence by the nanothermometers themselves, and solvent optical absorption. This work concludes that rare-earth-doped luminescent nanothermometers are not as reliable as thought and, consequently, special care has to be taken when extracting temperature estimations from the variation of their emission spectra.
关键词： reliability,solvent absorption,self-absorption,excitation power dependence,infrared luminescent nanothermometers,rare-earth-doped
更新于2025-09-19 17:15:36
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Prediction of Thermal Coupled Thermometric Performance of Er <sup>3+</sup>
摘要： Predicting thermometric performance for diverse materials will facilitate the selection and design of nanothermometers to meet complex environment and specific signal output with saving a lot of time and expense. Herein we explore and unveil the thermal coupled thermometric performance of Er3+/Yb3+ co-doped a set of host lattices via the chemical bond theory of complex crystals. The unknown B and ΔE values of the thermometry are accurately estimated by the chemical bond parameters, further deepening our cognition of the correlation between luminescence properties of Er3+ ions and microscopic crystal structure. This allows us to precisely forecast the thermal coupled thermometric performance of Er3+ for varying host lattices in advance.
关键词： nanothermometers,chemical bond theory of complex crystals,thermally coupled levels,rare earth,luminescence intensity ratio thermometry
更新于2025-09-11 14:15:04
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Surface state-controlled C-dot/C-dot based dual-emission fluorescent nanothermometers for intra-cellular thermometry
摘要： Fluorescence-based nanothermometers have potential to offer accuracy in the measurement of temperature using non-contact approaches. Herein, a C-dot/C-dot based dual-emission temperature sensing platform is fabricated through the electrostatic self-assembly of two kinds of fluorescent CDs with opposite charges. This dual-emission platform consists of several nearly-spherical CDs with two emission centers in blue (440 nm) and orange (590 nm) regions. The orange fluorescence exhibits discernible response to external temperatures in the range of ～15 to 85 °C; on the other hand, the blue fluorescence remains nearly constant. A continuous fluorescence color change in response to temperature from orange to blue can be clearly observed by the naked eye. Thus, the as-prepared C-dot based dual-emission nanospheres can be used for optical thermometry with high reproducibility and sensitivity (0.93%/°C). Detailed characterization shows that temperature (in the 15–85 °C window) impacts the surface states of orange emissive CDs, leaving the blue emissive CDs unaffected. A model is proposed to explain the observations. Finally, by taking advantage of the excellent biocompatibility and stability, the CD based fluorescent nanothermometer is successfully used for the visual measurement of intracellular temperature variations.
关键词： intracellular thermometry,temperature sensing,nanothermometers,dual-emission,fluorescence,carbon dots
更新于2025-09-11 14:15:04
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Lanthanide-Based Thermometers: At the Cutting-Edge of Luminescence Thermometry
摘要： Present technological demands in disparate areas, such as microfluidics and nanofluidics, microelectronics and nanoelectronics, photonics and biomedicine, among others, have reached to a development such that conventional contact thermal probes are not accomplished anymore to perform accurate measurements with submicrometric spatial resolution. The development of novel noncontact thermal probes is, then, mandatory, contributing to an expansionary epoch of luminescence thermometry. Luminescence thermometry based on trivalent lanthanide ions has become very popular since 2010 due to the unique versatility, stability, and narrow emission band profiles of the ions that cover the entire electromagnetic spectrum with relatively high emission quantum yields. Here, a perspective overview on the field is given from the beginnings in the 1950s until the most recent cutting-edge examples. The current movement toward usage of the technique as a new tool for thermal imaging, early tumor detection, and as a tool for unveiling the properties of the thermometers themselves or of their local neighborhoods is also summarized.
关键词： Luminescent Nanothermometers,Early Tumor Detection,Luminescence Thermometry,Lanthanide-Based Thermometers,Thermal Imaging
更新于2025-09-10 09:29:36