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ZnSe and ZnS nanocrystals (NCs) were precipitated in glasses through heat-treatment. High resolution transmission electron microscope image confirmed that ZnSe NCs were formed in the silicate glasses, and the X-ray diffraction patterns confirmed that ZnS NCs were precipitated in the borosilicate glasses. Absorption shoulders of the ZnSe NCs and ZnS NCs appeared at ~ 2.76 eV and ~ 3.78 eV, corresponding to the bandgap energies of bulk ZnSe and ZnS crystals, respectively. Instead of the intrinsic emissions, broad-band visible photoluminescence from the surface defects or color centers in the glasses was observed from these ZnSe or ZnS NCs. [ABSTRACT FROM AUTHOR]

Distribution and roles of rare earth ions in fluoride nanocrystals and lead chalcogenide quantum dots formed in glasses are reported. High-resolution transmission electron microscopic analysis and electron energy loss spectroscopic ( EELS) analysis showed that oxyfluoride glasses initially form crystals with high Er3+ content such as PbErF5 during heating and gradually form crystals with low Er3+ concentration. Amount of PbErF5 crystals depended upon the initial concentration of Er3+ ions in the parent glasses. EELS analysis also showed that Nd3+ ions were formed inside PbS quantum dots, supporting the proposition of the formation of Nd-O clusters. [ABSTRACT FROM AUTHOR]

Abstract: Optical properties of PbS quantum dots (QDs) precipitated inside the oxide glass matrix were investigated. Photoluminescence (PL) from the PbS QDs showed peak wavelengths located at 1170–1680nm with widths of 150–550nm. Radii of QDs in glasses were 2.3–4.7nm depending upon the thermal treatment. Peak wavelengths of PL bands shifted as much as 70nm as the temperatures and excitation irradiances increased. Calculated effective local temperatures indicated that these shifts of PL spectra were associated with local heating induced by the temperatures and laser beam. [Copyright &y& Elsevier]

Functional nanoparticles (NPs) hold immense promise in diverse fields due to their unique biological, chemical, and physical properties associated with size or morphology. Microfluidic technologies featuring precise fluid manipulation have become versatile toolkits for manufacturing NPs in a highly controlled manner with low batch-to-batch variability. In this review, we present the fundamentals of microfluidic fabrication strategies, including mixing-, droplet-, and multiple field-based microfluidic methods. We highlight the formation of functional NPs using these microfluidic reactors, with an emphasis on lipid NPs, polymer NPs, lipid-polymer hybrid NPs, supramolecular NPs, metal and metal-oxide NPs, metal–organic framework NPs, covalent organic framework NPs, quantum dots, perovskite nanocrystals, biomimetic NPs, etc. we discuss future directions in microfluidic fabrication for accelerated development of functional NPs, such as device parallelization for large-scale NP production, highly efficient optimization of NP formulations, and AI-guided design of multi-step microfluidic reactors. [ABSTRACT FROM AUTHOR]

Abstract: PbSe quantum dots (QDs) were synthesized in borosilicate glass and their optical properties were investigated. The typical quantum confinement effects were clearly observed from the absorption when the average radii of the QDs changed from 1.7 to 3.1nm. Photoluminescence from PbSe QDs was achieved in 1.1–2.2μm wavelength region that covers the entire fiber-optic telecommunication window. Borosilicate glasses containing controlled size of PbSe QDs provide potentials for the fiber-optic amplifiers. [Copyright &y& Elsevier]

In this work, PbSe QDs were precipitated in oxyfluoride glass-ceramics containing BaF2 nanocrystals. Tunable and broad absorption and photoluminescence from PbSe QDs doped glass-ceramics were observed in the near-infrared wavelength range. When the glasses were heat-treated at temperatures below 560°C using one-step heat-treatment schedule, single photoluminescence band was observed from each sample. Upon high temperature (560°C or 570°C) one-step or two-step heat-treatment, dual-band photoluminescence was observed. These two photoluminescence bands in each spectrum were separated by a gap of ~110–150meV, and as a result, effective full width at half maximum as large as ~500nm was recorded. [ABSTRACT FROM AUTHOR]

Pb 1-x Sr x Se quantum dots (QDs) were prepared in Li 2 O-Al 2 O 3 -SiO 2 (LAS) glass-ceramics with 0–2.0 mol% SrO by conventional melt-quenching method. The near-infrared photoluminescence and photodarkening properties of Pb 1-x Sr x Se QDs in LAS glass-ceramics were studied. Upon the heat treatments of 490–550 °C for 10 h, there are LiAlO 2 nanocrystals and PbSe QDs co-existed in the glassy matrix without SrO, and 1024–1745 nm near infrared emission from PbSe QDs were realized. With the increasing of SrO concentration from 0 to 2 mol%, the absorption wavelengths blue-shifted from 1738 to 1380 nm at 540 °C, the PL peak wavelengths blue-shifted from 1788 to 1538 nm at 540 °C. The blue-shifts are attributed to the increasing bandgap by incorporation of Sr2+ ions into PbSe crystalline lattice. Pb 1-x Sr x Se QDs display better photoinduced anti-darkening properties than pure PbSe QDs with the increasing of pumping power, and the Pb 1-x Sr x Se QDs embedded in the LAS glass with 2.0 mol% SrO shows the highest photoluminescence quantum yield of ∼36.9%. [Display omitted] [ABSTRACT FROM AUTHOR]

The treatment of Alzheimer's disease (AD) has been hampered by a lack of sensitive and specific non-invasive diagnostic methods. Quantum dots (QD) are nano-crystals with unique photo-physical properties that bypass some of the limitations of conventional dyes and imaging tools. This study is aimed to evaluate the fluorescence properties of a QD probe conjugated with an anti-Aβ antibody (QD-Aβ-Ab). Healthy mice and mice bearing mutated human APP695swe and APP717 V- F transgenes received intracerebroventricular injection of the probe for subsequent imaging. Immunohistochemistry revealed that Aβ was distributed in the hippocampus CA1 area in the APP transgenic mice. Fluorescence microscopy demonstrated that fluorescence was mainly observed in the hippocampus area, the cerebral cortex, sagittal septum and striatum of APP transgenic mice. In vivo imaging of mice receiving the QD-Aβ-Ab probe showed that healthy mice exhibited a narrow range of fluorescence and lower fluorescence intensity compared with APP transgenic mice. The mean fluorescence intensity of brain tissues of healthy C57BL mice was 12.3784 ± 3.9826, which was significantly lower than that of 10- and 16-month-old APP transgenic mice (45.03 ± 2.66 and 46.69 ± 3.22, respectively; P < 0.05). In this study we present the first direct evidence that QD-Aβ-Ab conjugate probes can track in vivo state of Aβ accumulation in mice and the findings suggest that such probes may be of potential use for early molecular diagnostic imaging of AD. [ABSTRACT FROM AUTHOR]