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Transparent luminescent solar concentrators (TLSCs) have been attracting wide attentions for their applications in transparent photovoltaic (PV) windows, smart greenhouses, and mobile electronics on account of the simple architecture and low-cost preparation. We report a novel strategy to fabricate TLSCs using the heterophase lead-free perovskites. The heterophase nanolayered films which combined CsCu2I3 and Cs3Cu2I5 were prepared in one step using a dual-source coevaporation technique. The CsCu2I3/Cs3Cu2I5 films exhibited UV light absorption, a high average visible transmission (AVT) of 86.70%, and dual-color white emission between 350 and 760 nm. Importantly, the TLSCs incorporated with the CsCu2I3/Cs3Cu2I5 films exhibited an impressive optical conversion efficiency of 1.15% under keeping a high AVT of 86.70%. Meanwhile, the TLSCs incorporated with the heterophase films showed considerable stability under ambient conditions. The CIE 1960 color coordinates (0.2082, 0.4680) of the TLSCs incorporated with the CsCu2I3/Cs3Cu2I5 films showed excellent aesthetic quality as compared with those of the TLSCs incorporated with lead-based perovskites. Our finding offers a strategy to prepare lead-free metal halides toward high-performance TLSCs and future transparent PV windows.

This work demonstrates a simple approach to rational fabrication of multishelled hollow silica spheres via periodic injections of a given amount of tetramethylammonium hydroxide (TMAH) to catalyze ...

In this paper, an oxide upconversion nanomaterial, Gd2O3:Ln3+, as an alternative counterpart of NaGdF4:Ln3+ was developed via controlled surfactant-free synthesis, flexible lanthanide loading, compositional/size tuning, hexagonal-to-cubic lattice refinement, and positive surface charging to achieve a substantial enhancement of upconversion luminescence (∼30 times upon calcination at 1000 vs 600 °C; ∼4000 times versus its hydroxide form) due to high crystallinity and extremely low residual impurities for white emission and cellular imaging. Nanyang Technological University Accepted version This work is supported by School of Materials Science and Engineering of Nanyang Technological University and Institute of Materials Research and Engineering for funding support. Electron microscopy and XRD were performed at the Facility for Analysis, Characterization, Testing and Simulation, Nanyang Technological University, Singapore.

Chemically engineered holes on two-dimensional (2D) nanomaterials may significantly increase the number of edge sites to tune their intrinsic properties to achieve promising performance. Here, we report a general and mild approach to the convenient creation of holes on atomically thin nanosheets for engineering bandgaps and enhancing properties of 2D materials. Through surface blocking, controlled dissolution, and chemical stabilization, WO3 nanosheets are readily treated to create holes in the presence of bovine serum albumin (BSA) via the reaction of WO3 with OH– ions at pH 8. Arising from the increased bandgaps and more edge sites as demonstrated experimentally and theoretically, the resulting holey WO3 nanosheets exhibit enhanced photocurrents and much better performance during selective adsorption and photocatalytic degradation compared with those of bulky WO3 and nonporous nanosheets. Also, this approach is further extended to the convenient creation of holes on more 2D nanomaterials such as MoS2 an...

Copper-based multinary sulfides (CMSs) have been the subject of intense research over the past decade due to the numerous outstanding properties that emerge when they are synthesized on the nanoscale. CMS compounds (e.g., CuInS2, Cu2SnS3, Cu12Sb4S13, and Cu2ZnSnS4) are best known for their immense potential in energy-related disciplines. Through nanoscale engineering, new and exciting opportunities have opened up for these materials to be used in a wider range of applications. This review accords particular attention to nanostructured CMS materials with porous morphological features to be used in energy, biomedical, catalytic, and sensing applications owing to their large, tunable, and accessible surface area. Although the construction of porous nanostructures of metals and binary materials has already been well established, tailoring porosity in multinary materials like CMSs remains a big challenge due to their multiple elemental components. Herein, we provide useful discussions on the different modes of...

The interleukin-6 (IL-6)/signal transducer and activator of transcription (STAT)-3 signaling pathway regulates proliferation and survival of intestinal epithelial cells and has profound impact on the tumorigenesis of colitis-associated cancer (CAC). Tea polysaccharides (TPS) are the major nutraceutical component isolated from tea-leaves and are known to possess antioxidant, anti-inflammatory, and antitumor bioactivities. Here, we investigated the antitumor activities of TPS on CAC using the azoxymethane/dextran sulfate sodium (AOM/DSS) mouse model and IL-6-induced colorectal cancer cell line (CT26) and determined whether TPS exerted its antitumor effects through the IL-6/STAT3 pathway. Results demonstrated that TPS significantly decreased the tumor incidence, tumor size, and markedly inhibited the infiltration of pro-inflammatory cells and the secretion of pro-inflammatory cytokines via balancing cellular microenvironment. Furthermore, we found that TPS suppressed the activation of STAT3 and transcriptionally regulated the expressions of downstream genes including MMP2, cyclin Dl, survivin, and VEGF both in vivo and in vitro. Thus, it was concluded that TPS attenuated the progress of CAC via suppressing IL-6/STAT3 pathway and downstream genes' expressions, which indicated that TPS may be a hopeful antitumor agent for the prevention and treatment of colon cancer.

As a light-activated noninvasive cancer treatment paradigm, photodynamic therapy (PDT) has attracted extensive attention because of its high treatment efficacy and low side effects. Especially, spatiotemporal control of singlet oxygen (1O2) release is highly desirable for realizing on-demand PDT, which, however, still remains a huge challenge. To address this issue, a novel switchable near-infrared (NIR)-responsive upconversion nanoprobe has been designed and successfully applied for controlled PDT that can be optically activated by tumor-associated disruption of labile Zn2+ (denoted as Zn2+ hereafter) homeostasis stimuli. Upon NIR irradiation, this theranostic probe can not only quantitatively detect the intracellular endogenous Zn2+ in situ but also selectively generate a great deal of cytotoxic reactive oxygen species (ROS) for efficiently killing breast cancer cells under the activation of excessive endogenous Zn2+, so as to maximally avoid adverse damage to normal cells. This study aims to propose a ...

Fluorescent colorimetry test papers are promising for the assays of environments, medicines, and foods by the observation of the naked eye on the variations of fluorescence brightness and color. Unlike dye-absorption-based pH test paper, however, the fluorescent test papers with wide color-emissive variations with target dosages for accurate quantification remain unsuccessful even if the multicolorful fluorescent probes are used. Here, we report the dosage-sensitive fluorescent colorimetry test paper with a very wide/consecutive "from red to cyan" response to the presence and amount of arsenic ions, As(III). Red quantum dots (QDs) were modified with glutathione and dithiothreitol to obtain the supersensitivity to As(III) by the quenching of red fluorescence through the formation of dispersive QDs aggregates. A small amount of cyan carbon dots (CDs) with spectral blue-green components as the photostable internal standard were mixed into the QDs solution to produce a composited red fluorescence. Upon the addition of As(III) into the sensory solution, the fluorescence color could gradually be reversed from red to cyan with a detection limit of 1.7 ppb As(III). When the sensory solution was printed onto a piece of filter paper, surprisingly a serial of color evolution from peach to pink to orange to khaki to yellowish to yellow-green to final cyan with the addition of As(III) was displayed and clearly discerned the dosage scale as low as 5 ppb. The methodology reported here opens a novel pathway toward the real applications of fluorescent test papers.

Semiconductor nanostructures that can effectively serve as light-responsive photocatalysts have been of considerable interest over the past decade. This is because their use in light-induced photocatalysis can potentially address some of the most serious environmental and energy-related concerns facing the world today. One important application is photocatalytic hydrogen production from water under solar radiation. It is regarded as a clean and sustainable approach to hydrogen fuel generation because it makes use of renewable resources (i.e., sunlight and water), does not involve fossil fuel consumption, and does not result in environmental pollution or greenhouse gas emission. Another notable application is the photocatalytic degradation of nonbiodegradable dyes, which offers an effective way of ridding industrial wastewater of toxic organic pollutants prior to its release into the environment. Metal oxide semiconductors (e.g., TiO2) are the most widely studied class of semiconductor photocatalysts. Their nanostructured forms have been reported to efficiently generate hydrogen from water and effectively degrade organic dyes under ultraviolet-light irradiation. However, the wide band gap characteristic of most metal oxides precludes absorption of light in the visible region, which makes up a considerable portion of the solar radiation spectrum. Meanwhile, nanostructures of cadmium chalcogenide semiconductors (e.g., CdS), with their relatively narrow band gap that can be easily adjusted through size control and alloying, have displayed immense potential as visible-light-responsive photocatalysts, but the intrinsic toxicity of cadmium poses potential risks to human health and the environment. In developing new nanostructured semiconductors for light-driven photocatalysis, it is important to choose a semiconducting material that has a high absorption coefficient over a wide spectral range and is safe for use in real-world settings. Among the most promising candidates are the multinary chalcogenide semiconductors (MCSs), which include the ternary I-III-VI2 semiconductors (e.g., AgGaS2, CuInS2, and CuInSe2) and the quaternary I2-II-IV-VI4 semiconductors (e.g., Cu2ZnGeS4, Cu2ZnSnS4, and Ag2ZnSnS4). These inorganic compounds consist of environmentally benign elemental components, exhibit excellent light-harvesting properties, and possess band gap energies that are well-suited for solar photon absorption. Moreover, the band structures of these materials can be conveniently modified through alloying to boost their ability to harvest visible photons. In this Account, we provide a summary of recent research on the use of ternary I-III-VI2 and quaternary I2-II-IV-VI4 semiconductor nanostructures for light-induced photocatalytic applications, with focus on hydrogen production and organic dye degradation. We include a review of the solution-based methods that have been employed to prepare multinary chalcogenide semiconductor nanostructures of varying compositions, sizes, shapes, and crystal structures, which are factors that are known to have significant influence on the photocatalytic activity of semiconductor photocatalysts. The enhancement of photocatalytic performance through creation of hybrid nanoscale architectures is also presented. Lastly, views on the current challenges and future directions are discussed in the concluding section.

In this article, Drosophila larvae are applied as an in vivo model to investigate the transport and uptake of polymeric nanoparticles in the larval digestive tract after oral administration. After feeding the larvae with food containing bare and chitosan-coated Poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles encapsulated with BODIPY, time-lapse imaging of live larvae is used to monitor the movement of fluorescent nanoparticles in the anterior, middle, and posterior midgut of the digestive tract. Also, the dissection of the digestive tract enables the analysis of cellular uptake in the midgut. Bare PLGA nanoparticles travel through the whole midgut smoothly while chitosan-coated PLGA nanoparticles have a long retention time in the posterior midgut. We identify that this retention occurs in the posterior segment of the posterior midgut, and it is termed as the retention segment. During transport in the midgut, chitosan-coated nanoparticles pass through the near-neutral anterior midgut and become high...

Studies reveal that biomolecules can form intriguing molecular structures with fascinating functionalities upon interaction with graphene. Then, interesting questions arise. How does silk fibroin interact with graphene? Does such interaction lead to an enhancement in its mechanical properties? In this study, using large-scale molecular dynamics simulations, we first examine the interaction of graphene with several typical peptide structures of silk fibroin extracted from different domains of silk fibroin, including pure amorphous (P1), pure crystalline (P2), a segment from N-terminal (P3), and a combined amorphous and crystalline segment (P4), aiming to reveal their structural modifications. Our study shows that graphene can have intriguing influences on the structures formed by the peptides with sequences representing different domains of silk fibroin. In general, for protein domains with stable structure and strong intramolecular interaction (e.g., β-sheets), graphene tends to compete with the intramolecular interactions and thus weaken the interchain interaction and reduce the contents of β-sheets. For the silk domains with random or less ordered secondary structures and weak intramolecular interactions, graphene tends to enhance the stability of peptide structures; in particular, it increases the contents of helical structures. Thereafter, tensile simulations were further performed on the representative peptides to investigate how such structure modifications affect their mechanical properties. It was found that the strength and resilience of the peptides are enhanced through their interaction with graphene. The present work reveals interesting insights into the interactions between silk peptides and graphene, and contributes in the efforts to enhance the mechanical properties of silk fibroin.

White-light-emitting materials for the applications in display and lighting have widely been prepared by the rare earth with high photoluminescent efficiency and stability, but the short resource, ...

Single-phase “greener” phosphor with broadband emission made of colloidal quantum dots (QDs) is most desirable for use as color convertors in white light-emitting diodes (WLEDs). Here, we demonstrate a single “cadmium-free” component system consisting of Cu-doped InP core/ZnS barrier/InP quantum well/ZnS shell QDs, which exhibits two emission peaks by controlling the barrier thickness under single-excitation wavelength, one of which being attributed to Cu-doped InP, and the other resulting from InP quantum well. The dual emissive peaks were successfully tuned in a range from visible to near-infrared by simple control of the core size and the well thickness, respectively. Using optimal structures as color converters, we successfully obtained WLED with a color rending index (CRI) up to 91 and CIE color coordinates of (0.338, 0.330) by combination with blue LED chip, indicating this single-phase phosphor with great promise for use in solid-state lighting due to flexibly tunable dual emission peak position in...

Site and size control of ordered arrays of semiconductor nanostructures in an efficient way has remained a large challenge and has thus attracted intensive research interest due to their potential applications in integrated optoelectronics. In this work, we report an original approach to grow hexagonally ordered arrays of InGaAs/GaAs nanobars on the designed regions of GaAs substrate coated with silicon dioxide through nanosphere lithography (NSL). To control the growth sites of the nanostructures, microsized wells are first fabricated on a thin silicon dioxide film deposited on the GaAs substrate by photolithography, and bilayers of hexagonally ordered polymer nanospheres are then self-assembled on the silicon dioxide films with two different thicknesses. Finally, an array of nanocavities is created by dry etching through the self-assembled nanospheres. By controlling the etching depth, the nanocavities are etched down to the GaAs substrate first in the wells, leading to epitaxial growth of InGaAs/GaAs n...

Growing oxide shells on seed nanoparticles requires the control of several processes: (a) the nucleation and growth of the shell material; (b) the "wetting" of the shell material on the seeds; and (c) the aggregation of the nanoparticles. These processes are influenced by a number of factors, many of which are related. Without understanding the interdependence of these contributing factors, it is difficult to circumvent problems and achieve rational synthesis. We first did a case study on encapsulating Au nanoparticles with ZnO to understand the multiple roles of polyvinylpyrrolidone (PVP) and their dependence on other factors. We developed a general method for coating ZnO on a variety of seeds, including metals, oxides, polymer nanoparticles, graphene oxide, and carbon nanotube. This method can be further extended to include Fe3O4, MnO, Co2O3, TiO2, Eu2O3, Tb2O3, Gd2O3, β-Ni(OH)2, ZnS, and CdS as the shell materials. The understanding obtained in this systematic study will aid rational design and synthesis of other core-shell nanostructures.

To achieve selectivity in direct chemiluminescence (CL) detection is very significant and a great challenge as well. Here, we report a novel concept of developing intrinsically selective CL switching at the surface of Fe(3)O(4) nanoparticles for the sensitive detection and simultaneous determination of various pesticides. Fe(3)O(4) nanoparticles have peroxidase-like catalytic activity and catalyze the decomposition of dissolved oxygen to generate superoxide anions, so that the CL intensity of luminol was amplified by at least 20 times. The CL signals can be quenched by the addition of ethanol because ethanol readily reacts with superoxide anions as a radical scavenger. However, the quenching effect can be inhibited through the specific binding of target molecules on Fe(3)O(4) nanoparticles, leading to CL "turn-on" in the presence of ethanol. The novel CL "switching-on" concept demonstrated unique advantages in the detection of pesticide residues. Using the surface coordinative reactions, nonredox pesticide ethoprophos were sensitively detected with a detection limit of 0.1 nM and had a very wide detection range of 0.1 nM to 100 μM. More importantly, the selectivity of CL switching is tunable through the special surface modification of Fe(3)O(4) nanoparticles, and these Fe(3)O(4) nanoparticles with different surface groups can generate unique CL response pattern for the simultaneous determination of various pesticides. Meanwhile, the superparamagnetic properties of Fe(3)O(4) nanoparticles provide a simple magnetic separation approach to attain interference-free measurement for real detection. The very facile and versatile strategy reported here should open a new window to exploration of selective CL molecular switching and application of magnetic nanoparticles for chemo/biodetection.

Here, we report a general protocol for coating molecularly imprinted polymers (MIPs) at the superparamagnetic iron oxide nanoparticles (Fe3O4 NPs) to make highly controllable core–shell Fe3O4@MIP NPs for rapid enrichment and separation of herbicides in water. Acrylic acid monomers were first anchored at the surface of Fe3O4 by the simple complexing reaction with unsaturated iron ions at the nanoparticle surface, which forms a polymerizable molecule monolayer. It was found that the monolayer highly directed the selective occurrence of molecular imprinting polymerization at the surface of Fe3O4 NPs, and the homogeneous copolymerization in solution phase was completely prohibited by the optimized reaction conditions. As a result, one can easily produce the uniformly spherical Fe3O4@MIP NPs with tunable MIP shell thickness from several to tens of nanometers that can simply be achieved by changing the amounts of precursors. The Fe3O4@MIP NPs with saturation magnetization of 38 emu/g exhibit the capability of u...

We report a facile chemical synthesis of well-defined gold nanocrosses through anisotropic growth along both110and001, whereas gold nanorods grow only along either110or001. The multiple branching was achieved by breaking the face-centered-cubic lattice symmetry of gold through copper-induced formation of single or double twins, and the resulting gold nanocrosses exhibited pronounced near-IR absorption with a great extension to the mid-IR region. As studied by discrete dipole approximation (DDA) simulations, the entire nanocross gets excited even when one of the branches is exposed to incident light. The above properties make them useful as octopus antennas for capturing near-IR light for effective photothermal destruction of cells. The cell damage process was analyzed using the Arrhenius model, and its intrinsic thermodynamic characteristics were determined quantitatively. Besides effective photothermal treatment and two-photon luminescence imaging, the near- and mid-IR-absorbing gold nanocrosses may also find applications in IR sensing, thermal imaging, telecommunications, and the like.

Nanodisk heterostructures consisting of monoclinic Cu(1.94)S and wurtzite CdS have been colloidally synthesized for the first time. Initially, hexagonal-shaped nanodisks of Cu(1.94)S were produced upon thermolysis of a copper complex in a solvent mixture of HDA and TOA at 250 °C. Rapid addition of Cd precursor to the reaction mixture resulted in the partial conversion of Cu(1.94)S into CdS, yielding Cu(1.94)S-CdS nanoheterostructures. The original morphology of the Cu(1.94)S nanodisks was conserved during the transformation. When Zn precursor was added together with the Cd precursor, Cu(1.94)S-Zn(x)Cd(1-x)S nanodisks were generated. These two-component nanostructures are potentially useful in the fabrication of heterojunction solar cells.

The ability to engineer the band gap energy of semiconductor nanocrystals has led to the development of nanomaterials with many new exciting properties and applications. Band gap engineering has thus proven to be an effective tool in the design of new nanocrystal-based semiconductor devices. As reported in numerous publications over the last three decades, tuning the size of nanocrystalline semiconductors is one way of adjusting the band gap energy. On the other hand, research on band gap engineering via control of nanocrystal composition, which is achieved by adjusting the constituent stoichiometries of alloyed semiconductors, is still in its infancy. In this Account, we summarize recent research on colloidal alloyed semiconductor nanocrystals that exhibit novel composition-tunable properties. Alloying of two semiconductors at the nanometer scale produces materials that display properties distinct not only from the properties of their bulk counterparts but also from those of their parent semiconductors. As a result, alloyed nanocrystals possess additional properties that are composition-dependent aside from the properties that emerge due to quantum confinement effects. For example, although the size-dependent emission wavelength of the widely studied CdSe nanocrystals can be continuously tuned to cover almost the entire visible spectrum, the near-infrared (NIR) region is far outside its spectral range. By contrast, certain alloy compositions of nanocrystalline CdSe(x)Te(1-x), an alloy of CdSe and CdTe, can efficiently emit light in the NIR spectral window. These NIR-emitting nanocrystals are potentially useful in several biomedical applications. In addition, highly stable nanocrystals formed by alloying CdSe with ZnSe (i.e., Zn(x)Cd(1-x)Se) emit blue light with excellent efficiency, a property seldom achieved by the parent binary systems. As a result, these materials can be used in short-wavelength optoelectronic devices. In the future, we foresee new discoveries related to these interesting nanoalloys. In particular, colloidal semiconductor nanoalloys that exhibit composition-dependent magnetic properties have yet to be reported. Further studies of the alloying mechanism are also needed to develop improved synthetic strategies for the preparation of these alloyed nanomaterials.

Single-walled carbon nanotubes (SWNTs) are stabilized with sodium dodecyl sulfate (SDS) micelles in aqueous solution. Aggregation among semiconducting SWNTs can be identified by exciton energy transfer (EET) features in photoluminescence excitation (PLE) mapping. Addition of o-dichlorobenzene (ODCB) not only changes the micelle structure but also induces the aggregation among SWNT species, leading to drastic changes in the EET features of the ensemble. Force-field and molecular dynamic simulation confirm that SWNT bundles are energetically favorable at room temperature. Observed EET features in PLE mappings are found to be SWNT species-dependent. Moreover, the rapid bundling process induced by ODCB allows us to obtain SWNT bundles which are potentially useful for optical and optoelectronic applications.

In this article, we have demonstrated one-step solid-phase transformation from high-quality cadmium carbonate microcrystals into highly nanoporous cadmium oxide. The high crystal quality of cadmium carbonate is critical for the successful fabrication of porous nanoarchitectures with predetermined morphology and well-controlled internal structure. This novel strategy has a good potential to prepare nanoporous materials at a large scale by using perfect monolithic carbonate crystals, and it is also useful to synthesize different nanoporous materials on metal-oxide-coated substrates. Meanwhile, this simple thermal transformation of cadmium carbonate into porous structures has further been extended to convert calcium carbonate into such porous structures.

Various diversified morphology-modulated ZnO nanostructures including nanorods, nanotetrahedrons, nanofans, nanodumbbells, and nanosquamas have been successfully prepared via an effective aminolytic reaction of zinc carboxylates with oleylamine in noncoordinating and coordinating solvents. Their shape- and structural defect-dependent optical properties have been investigated as well. Highly crystalline defect-free nanotetrahedrons/nanorods have a sharp band-edge emission, and highly defective nanodumbbells/nanosquamas show a very broad deep-trap emission, resulting from the radiative recombination of electrons with holes in singly ionized oxygen vacancies.