Exploring CsPbX3 (X = Cl, Br, I) Perovskite Nanocrystals in Amorphous Oxide Glasses: Innovations in Fabrication and Applications.

Metal halide perovskites with excellent optical and electronic properties have become a trending material in the current research. However, their limited stability under ambient conditions degrades quality and threatens their potential commercialization as optoelectronic devices. Various approaches are adopted to improve the stability of perovskite nanocrystals (PeNC) while maintaining their advantageous optical properties, particularly strong luminescence. Among different possible improvement strategies, encapsulation of PeNCs within the amorphous glass matrices of inorganic oxides has drawn widespread attention because it ensures high resistance against chemical corrosion and high temperature, thus enhancing their chemical, thermal, and mechanical stability with improved light-emission characteristics. In this article, two types of materials, namely all-inorganic metal halide PeNCs and amorphous oxide glasses are briefly introduced, and then the methods are reviewed to fabricate and improve the quality of PeNC@glass composites. These methods are classified into three universal categories: compositional modification, structural modification, and dual encapsulation. In the final part of this review paper, examples of applications of PeNCs@glass composites in light-emitting devices and displays, data storage and anti-counterfeiting, lasing, photodetectors and X-ray detectors, photocatalysis, optical filters, solar concentrators, and batteries are provided.

Correlation between effects of the particle size and magnetic field strength on the magnetic hyperthermia efficiency of dextran-coated magnetite nanoparticles.

A precise control of the particle size of dextran-coated magnetite nanoparticles (Dex-M NPs) was successfully performed by combination of co-precipitation and hydrothermal synthesis methods. The Dex-M NPs, in the size range 3.1-18.9 nm, were used to fabricate biocompatible magnetic fluids for application in magnetic hyperthermia therapy (MHT). The effects of the carrier fluid viscosity, particle size, and applied magnetic field strength (Happl) on the specific loss power (SLP) of the Dex-M NPs were investigated at a fixed magnetic field frequency (f). The experimental results show that SLP of the larger Dex-M NPs significantly decreases for a highly viscous carrier fluid. Moreover, regardless of the carrier fluid viscosity, the particle size strongly affects the heating efficiency of the Dex-M NPs. SLP ranges from zero for the smallest Dex-M NPs (with particle size d = 3.1 nm) to 55.21 W/g for the largest ones (d = 18.9 nm) at Happl = 28 kA/m and f = 120 kHz. The most important finding in our research is that, at a fixed frequency, the optimal size of the Dex-M NPs (the size that maximizes SLP) shows a rising trend by enhancing Happl. In fact, the highest values of SLP at Happl = 11 kA/m, 13 - 17.5 kA/m, and 19 - 28 kA/m are obtained for the Dex-M NPs with d = 11.5 nm, 15 nm, and 18.9 nm, respectively. The shift of optimal size to the higher values by increasing Happl could shed light on the correlated effects of the particle size and Happl on the heating efficiency of magnetic nanoparticles (MNPs) and pave a new way toward the better tuning of them for an effective and biologically safe treatment.

Luminescent, low-toxic and stable gradient-alloyed Fe:ZnSe(S)@ZnSe(S) core:shell quantum dots as a sensitive fluorescent sensor for lead ions.

In this paper, an aqueous-based approach is introduced for facile, fast, and green synthesis of gradient-alloyed Fe-doped ZnSe(S)@ZnSe(S) core:shell quantum dots (QDs) with intense and stable emission. Co-utilization of co-nucleation and growth doping strategies, along with systematic optimization of emission intensity, provide a well-controllable/general method to achieve internally doped QDs (d-dots) with intense emission. Results indicate that the alloyed ZnSe(S)@ZnSe(S) core:shell QDs have a gradient structure that consists of a Se-rich core and a S-rich shell. This gradient structure cannot only passivate the core d-dots by means of the wider band gap S-rich shell, but also minimizes the lattice mismatch between alloyed core-shell structures. Using this novel strategy and utilizing the wider band gap S-rich shell can obviously increase the cyan emission intensity and also drastically improve the emission stability against chemical and optical corrosion. Furthermore, the cytotoxicity experiments indicate that the obtained d-dots are nontoxic nanomaterials, and thus they can be considered as a promising alternative to conventional Cd-based QDs for fluorescent probes in biological fields. Finally, it is demonstrated that the present low-toxicity and gradient-alloyed core:shell d-dots can be used as sensitive chemical detectors for Pb2+ ions with excellent selectivity, small detection limit, and rapid response time.

Aqueous-based synthesis of Cd-free and highly emissive Fe-doped ZnSe(S)/ZnSe(S) core/shell quantum dots with antibacterial activity.

The effective insertion of intentional impurities in direct aqueous preparation of doped QDs still needs a chemical route with well-designed strategy. The present work reports a facile, one-pot, and aqueous-based method for green synthesis of Fe-doped ZnSe(S)/ZnSe(S) core/shell QDs with improved emission intensity. In the proposed strategy, by using a sulfur rich ZnSe(S) shell, we can provide a wider band gap shell with low structural defects in the interface between core and shell. Utilization of combined co-nucleation and growth doping strategies along with increasing the shell refluxing time all are the chemo-physical tactics which led to high intensity dopant-related emission. The antibacterial activity of the as-prepared doped core/shell QDs was investigated using agar disk diffusion method. The results show, these QDs have a significant antibacterial activity against different pathogenic bacteria comparing with the conventional antibiotics. The facility of suggested aqueous route for reaching a dopant emission, the bio-compatibility and considerable antibacterial characteristics of present QDs, nominate them as good candidates in further biological applications.

Physics responsible for heating efficiency and self-controlled temperature rise of magnetic nanoparticles in magnetic hyperthermia therapy.

Magnetic nanoparticles as heat-generating nanosources in hyperthermia treatment are still faced with many drawbacks for achieving sufficient clinical potential. In this context, increase in heating ability of magnetic nanoparticles in a biologically safe alternating magnetic field and also approach to a precise control on temperature rise are two challenging subjects so that a significant part of researchers' efforts has been devoted to them. Since a deep understanding of Physics concepts of heat generation by magnetic nanoparticles is essential to develop hyperthermia as a cancer treatment with non-adverse side effects, this review focuses on different mechanisms responsible for heat dissipation in a radio frequency magnetic field. Moreover, particular attention is given to ferrite-based nanoparticles because of their suitability in radio frequency magnetic fields. Also, the key role of Curie temperature in suppressing undesired temperature rise is highlighted.

High impact of in situ dextran coating on biocompatibility, stability and magnetic properties of iron oxide nanoparticles.

Biocompatible ferrofluids based on dextran coated iron oxide nanoparticles were fabricated by conventional co-precipitation method. The experimental results show that the presence of dextran in reaction medium not only causes to the appearance of superparamagnetic behavior but also results in significant suppression in saturation magnetization of dextran coated samples. These results can be attributed to size reduction originated from the role of dextran as a surfactant. Moreover, weight ratio of dextran to magnetic nanoparticles has a remarkable influence on size and magnetic properties of nanoparticles, so that the sample prepared with a higher weight ratio of dextran to nanoparticles has the smaller size and saturation magnetization compare with the other samples. In addition, the ferrofluids containing such nanoparticles have an excellent stability at physiological pH for several months. Furthermore, the biocompatibility studies reveal that surface modification of nanoparticles by dextran dramatically decreases the cytotoxicity of bare nanoparticles and consequently improves their potential application for diagnostic and therapeutic purposes.

Preparation of Highly Biocompatible ZnSe Quantum Dots Using a New Source of Acetyl Cysteine as Capping Agent.

In this paper, we describe a facile method for preparation of ZnSe quantum dots (QDs) using an inexpensive and biocompatible source of acetyl cysteine in aqueous media. The structural properties of the ZnSe QDs have been characterized using XRD, FT-IR, and TEM techniques. The optical properties of the as-prepared QDs were found to be size-dependent, due to the strong confinement regime at relatively low refluxing time. Effect of solution pH and refluxing temperature on absorption and emission characteristics of the ZnSe QDs was studied. The empirical effective mass approximation also reveals that, both solution pH and refluxing temperature parameters would effect on ZnSe QDs growth, and increase their size. However, the influence of the solution pH was found to be more prominent. Water-solubility, high emission intensity and sub-10 nm nanocrystals size are the most essential features that suggest our synthesized aqueous-based ZnSe QDs (with a very cost-effective and biocompatible capping agent) can be utilized for biological intentions.