Search

Fluorescent detection is a new spectroscopic measurement for ions sensing due to the advantages of real‐time determination with high selectivity, accuracy, and low cost. However, chemosensors based on fluorescent detection are usually determined by absolute intensity from a monochromatic emission signal, which is easy to be fluctuated by the external environment, especially for Fe3+ detection in complex fluids. Herein, we rationally design a dual‐emission Eu3+: CDs@ZIF‐8 to construct a ratiometric fluorescent sensor with self‐calibrating ability for Fe3+ determination. High efficient carbon dots (CDs) are embedded in europium ions (Eu3+)‐doped MOF by simple stirring preparation at room temperature. The label‐free ratiometric fluorescent probe (ICDs@ZIF‐8/IEu) exhibits simultaneous blue and red emission under the same excitation at 365 nm. Remarkably, Eu3+: CDs@ZIF‐8 displays the superiority of high selectivity to Fe3+, which shows ratiometric fluorescence characteristics (I0/I) in a range of 0‐6 μmol\L with a low limit of detection (LOD) of 0.897 μmol\L. Besides, the CDs‐MOF nanocomposite holds good aqueous dispersibility and low cytotoxicity, which shows great potential applications in medical aid including biological detection and clinical diagnosis. [ABSTRACT FROM AUTHOR]

Morphological control is a fundamental challenge of nanomaterial development. Commonly, hierarchical nanostructures cannot be induced by a single driving force, but obtained through balancing multiple driving forces. Here, a feasible strategy is reported based on the synergistic effect of proton and acid anion, leading to the morphological variation of vanadium oxide from nanowire, bundle, to hierarchical nanoflower (HNF). Protons can only induce the formation of nanowire through reducing the pH value ≤ 2. However, acid anions with strong coordination ability, e.g., phosphate radicals, can also participate in morphological regulation at high concentration. Through coordinating with exposed vanadium ions, the enrichment of phosphate radicals at ledge and kink changes the growth directions, giving rise to the advanced structures of bundle and HNF. The lithium ion batteries using HNF as a cathode achieve a 30% improved initial discharge specific capacity of 436.23 mAh g−1 at a current density of 0.1 A g−1, reaching the theoretical maximum value of vanadium oxide based on insertion/desertion of three lithium ions, in addition to strong cyclic stability at 1 A g−1. [ABSTRACT FROM AUTHOR]

By combining the spectroscopic quality of a crystalline phase with the outstanding thermal and chemical stability of the matrix glass, nanocrystal‐in‐glass composites (NGCs) exhibit excellent optical properties. However, strong interfacial diffusion occurs during high‐temperature encapsulation, leading to the erosion of the nanocrystals and detrimental effects on the final performance. The control of interfacial diffusion has so far relied on intuition and experience, with the underlying physical mechanisms remaining largely unknown. In this study, through atomistic simulations and experimental verification, we have developed atomic models of NGCs, revealing the dynamic characteristics of the interface and elucidating how the glass structure can regulate the interface diffusion. Finally, we demonstrate how a tunable interface can be achieved through compositional adjustments of the glass matrix. [ABSTRACT FROM AUTHOR]

Rare earth (RE) ions‐doped luminescent nanocrystals (NCs) with numerous unique advantages have attracted tremendous interest for the wide applications from science to engineering, yet suffering from the shortcoming of thermal quenching coming from surface organic ligands. We propose utilizing a facile acid‐base reaction to remove surface organic ligands introduced choosing carboxylic acids as stabilizing agent and weaken thermal quenching. The results showed that the acid‐base reaction displayed an outstanding cleaning effect. After acid‐treatment, most surface organic ligands were removed, and there was no influence on crystal structure and morphology of as‐prepared β‐NaYF4:Er3+ NCs. Meanwhile, with no surface organic ligands capping, β‐NaYF4:Er3+ NCs preferred brighter emission after thermal treatment, including up‐conversion (UC), near‐infrared (NIR), and mid‐infrared (MIR) emission. When calcined the acid‐treated β‐NaYF4:Er3+ NCs in different atmosphere, such as oxygen and reducing atmosphere (15%H2 + 85%N2), an unexpected enhancement of all emission bands in Er3+ was determined under phase transformation temperature, especially in oxygen atmosphere. Furthermore, all the fluorescence lifetimes of Er3+ also exhibited obvious extension. Our results supposed that the β‐NaYF4:Er3+ NCs have promising applications in safety ink, and the acid‐treatment by diluted hydrochloric acid is a general approach to remove deleterious organic ligands on NC surface further to weaken thermal quenching. [ABSTRACT FROM AUTHOR]

Illustration of ferroptosis therapy for the treatment of kidney cancer using Fe/Ni-LDH. GPX4: glutathione peroxidase 4, GSH: reduced glutathione, GSSG: oxidized glutathione, LOOH: lipid hydroperoxide, LOH: lipid alcohol. [Display omitted] • A general and facile method was proposed for synthesizing Fe/Ni-LDH to achieve apoptosis-enhanced and ferroptosis-involved cancer nanotherapy. • The Fe/Ni-LDH exhibited great ROS-generating catalytic activity for chemo-dynamic therapy, resulting in the apoptosis-induced cell death pathway, intracellular oxidative damage, and LPO accumulation to promote ferroptosis-involved cancer cell death. • The KEGG pathway enrichment and GSEA analyses of transcriptome sequencing indicated that ferroptosis was involved in Fe/Ni-LDH anti-tumor therapy. Nanocatalysts provide a platform for developing anti-tumor strategies by activating intratumoral chemical catalysis to produce highly toxic reactive oxygen species (ROS). However, the biological effect of nanocatalysts on tumor cells, which is pivotal for effective nanotherapy treatment, remains poorly understood. Herein, we present a general and facile method of synthesizing Fe/Ni-layered double hydroxides (LDHs) for enhanced apoptosis- and ferroptosis-induced cancer nano-therapy, as well as a potential mechanism underlying the anti-tumor effect based on transcriptome sequencing. An analysis of the chemical structure suggests that the Fe atoms interact strongly with the Ni atoms in Fe/Ni-LDH. Compared with Fe-OH and Ni-OH, Fe/Ni-LDH exhibited significantly better ROS-catalytic activity, with a V max of 5.015 × 10−2 μM·s−1, and generated massive amounts of •OH and O 2 •− radicals, enabling outstanding chemo-dynamic therapy. Both in vitro and in vivo experiments indicated a robust apoptosis-induced cell death pathway, increased intracellular oxidative stress, and accumulation of lipid peroxide (LPO), promoting ferroptosis-involved cancer-cell death, which was further confirmed by transcriptome sequencing. The Fe/Ni-LDH biocatalyst not only provides a robust nanoplatform for tumor suppression but also encourages further exploration and applications of nanobiocatalysts. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mono-dispersed ZnS: Mn nanocrystals were synthesized by a hydrothermal route. [•] Photoluminescence of nanocrystals were studied by steady and transient state spectra. [•] A novel energy transfer mechanism of ZnS: Mn nanocrystals was proposed. [ABSTRACT FROM AUTHOR]

With the rapidly increasing energy crisis and environment pollution, the development of renewable and clean energy sources has become indispensable. To this end, electrocatalytic oxygen evolution reaction (OER) plays a crucial role in advanced energy conversion and storage technologies such as water splitting and rechargeable metal-air batteries. Considerable efforts have been devoted to exploit non-precious metal catalysts for replacing the catalysts based on precious metals such as iridium (Ir) and ruthenium (Ru). However, a clear understanding of the OER mechanism of electrocatalysts is vital for the directional synthesis of high-performance electrocatalysts. In this review, the recent perspectives on OER mechanisms of non-precious metal-based catalysts are presented, which includes electron transfer, defect/vacancy, and electronic-configuration regulation structures. The construction strategies of electrocatalysts and fundamental mechanisms for enhancing the catalytic activity are discussed. Furthermore, the catalysts that can be beneficial for water splitting and metal-air batteries are introduced. Besides, an overview of past developments and future challenges is presented. Image 1 • Progress in OER catalytic mechanism and application is shown. • Techniques for identifying catalyst structures are discussed. • Challenges and future opportunities of OER catalysts are proposed. [ABSTRACT FROM AUTHOR]

Conventional near-infrared luminescent phosphors activated by transition metal elements or rare earth activators were already widely reported. In this work, we develop a self-activated near-infrared luminescent phosphor with a typical double perovskite structure, which exhibits an emission at 650–750 nm under excitation at 365 nm. The origin of the desired luminescence in (Ca,Sr)LaMgTaO 6 compounds is attributed to the oxygen vacancies defects, oxygen interstitial defects and substitution defects and antioccupation defects. Thermal quenching of photoluminescence is undesirable with an integrated emission loss of 30–50% at 150 °C, which needs to be improved. This new series of near-infrared luminescent materials have potential applications in agricultural cultivations and bio-imaging materials. More importantly, we demonstrate a strategy by self-activation to realize near-infrared light. [ABSTRACT FROM AUTHOR]

Rare earth doped mid-infrared (MIR) fluorescent sources have been widely investigated due to their various potential applications in the fields of communication, chemical detecting, medical surgery and so forth. However, with emission wavelength extended to MIR, multiphonon relaxation process that strongly quenched the MIR emission is one of the greatest challenges for such practical applications. In our design, we have described a controllable gas-aided annealing strategy to modulate the phase, crystal size, morphology and fluorescent performance of a material simultaneously. Uniform and monodispersed Er3+-doped La2O2S and La2O2SO4 nanocrystals with a similar lattice structure, crystallinity, diameter and morphology have been introduced to investigate the impact of multiphonon relaxation on luminescence performance. Detailed spectroscopic evolutions in the region of MIR, near-infrared (NIR), visible upconversion (UC) and their corresponding decay times provide insight investigation into the fluorescent mechanism caused by multiphonon relaxation. A possible energy transfer model has also been established. Our results present direct observation and mechanistic investigation of fluorescent evolution in multiphonon relaxation process, which is conductive to design MIR fluorescent materials in the future. To the best of our knowledge, it is the first investigation on MIR fluorescent performance of La2O2S nanocrystals, which may find various applications in many photoelectronic fields. [ABSTRACT FROM AUTHOR]

As an analog of graphite, graphitic carbon nitride (g-C3N4) has been the hotspot in the materials science for its unique electronic structure. With medium band gap as well as thermal and chemical stability in ambient environment, it becomes one of the most promising photocatalytic materials. Intensive investigation has been focus on its photocatalytic performance for various reactions to date. What is more, controllable modulation of its electronic structure via doping or chemical functionalization is available. In addition, considerable attention has been paid on its photoelectronic application, such as light emitting device, photocathode, optical sensor, etc. Based on the electronic properties and pathway to modulate its electronic structure, in this review, we highlight the applications of g-C3N4 ranging from photocatalytic to photoelectronic materials. [ABSTRACT FROM AUTHOR]

The application of graphitic carbon nitride (g‐C3N4) has been restricted in some optoelectronics fields due to its narrow tunable emission region. In order to engineer the optical properties, herein we combine Eu3+:Y2O3 nanocrystals with g‐C3N4to control its electronic structure. Surprisingly, with the increasing concentration of Eu3+:Y2O3 nanocrystals, the photoluminescence of Eu3+:Y2O3/g‐C3N4 (EYCN) showed a continuous red shift in comparison with pure g‐C3N4 from blue to green. In EYCN composites, the Eu3+:Y2O3 nanocrystals as electron donors, can improve the degree of electron delocalization and narrow the bandgap. Importantly, the EYCN composites not only maintain the intrinsic blue‐green emission of g‐C3N4, but also introduce the red light of Eu3+ ions. Based on the EYCN composites, white light‐emitting diode (WLED) were fabricated with a Commission International de L'Eclairage value of (0.3631, 0.3560). This work proposes a new kind of luminescent g‐C3N4‐based composites, which is expected to broaden its applications in optoelectronics field. [ABSTRACT FROM AUTHOR]