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A one‐step method to produce ≈12 nm hydrodynamic diameter water‐soluble CdSe/ZnS quantum dots (QDs), as well as CdS/ZnS, ZnSe/ZnMnS/ZnS, AgInS2/ZnS, and CuInS2/ZnS QDs, by ligand exchange with a near‐monolayer of organosilane caps is reported. The method cross‐links the surface‐bound silane ligands such that the samples are stable on the order of months under ambient conditions. Furthermore, the samples...
Solid‐state powders of CdTe quantum dots embedded in a NaCl matrix are applied as a highly sensitive probe for luminescence thermal imaging and sensing across a wide range of temperatures by A. L. Rogach and co‐workers on page 466. They show how the emission color changes over the whole spectral range from green to red as a function of temperature, and demonstrate that the luminescence originating...
Temperature‐dependent optical studies of semiconductor quantum dots (QDs) are fundamentally important for a variety of sensing and imaging applications. The steady‐state and time‐resolved photoluminescence properties of CdTe QDs in the size range from 2.3 to 3.1 nm embedded into a protective matrix of NaCl are studied as a function of temperature from 80 to 360 K. The temperature coefficient is found...
Tin‐based electrodes offer high theoretical capacities in lithium ion batteries, but further commercialization is strongly hindered by the poor cycling stability. An in situ reduction method is developed to synthesize SnO2 quantum dots@graphene oxide. This approach is achieved by the oxidation of Sn2+ and the reduction of the graphene oxide. At 2 A g−1, a capacity retention of 86% is obtained even...
FLIMaging nanoparticle degradation: semiconductor and metal nanoparticle degradation has been observed in live cells over 3 d via the change of the characteristic luminescence lifetime using fluorescence lifetime imaging microscopy (FLIM). Thus, FLIM is a simple yet robust tool to examine the intracellular stability of photoluminescent nanoparticles in live cells, tissues, and organisms.
PEG‐functionalized graphene quantum dots (GQDs) are shown to promote fast exciton dissociation in organic solar cells. Short‐chain PEG promotes the most favorable interaction with other organic layers, and the overall efficiency is improved by 36% when compared to the reference devices. The mechanism of enhancement is shown to be increased absorption due to fewer charges remaining in the bound state...
Synthesis of highly mono‐dispersed large PbS nanocrystals (NCs) with low particle size dispersion is demonstrated by F. So and co‐workers on page 1328, by controlling the sulfur concentration below the nucleation threshold during multiple injections of the sulfur precursor. These NCs are used to fabricate multi‐spectral photodetectors and high detectivity values in the UV‐Visible‐SWIR (short‐wave‐IR)...
Solution‐processed inorganic UV‐visible short‐wave‐infrared photodetectors with light sensitivity from 350 nm to 2000 nm are fabricated using highly monodispersed large PbS NCs. These devices showed detectivity values over 1 × 1011 Jones from 350 nm to 2000 nm, and a maximum detectivity value of 1.2 × 1012 Jones at 1800 nm.
The wide‐ranging applications of fluorescent semiconductor quantum dots (QDs) have triggered increasing concerns about their biosafety. Most QD‐related toxicity studies focus on the subcellular processes in cultured cells or global physiological effects on whole animals. However, it is unclear how QDs affect subcellular processes in living organisms, or how the subcellular disturbance contributes...
The systematic physiological behavior and toxicity of quantum dots (QDs) of three different sizes in Caenorhabditis elegans (C. elegans) is investigated by H. M. Zhang, Y. He, and co‐workers on page 3143. Endocytosis and nutrition storage are disrupted by QDs, which likely accounts for the severe deterioration in growth and longevity of C. elegans. The cover image shows the QDs exhibiting size‐dependent...
Currently, DNA nanotechnology offers the most programmable, scalable, and accurate route for the self‐assembly of matter with nanometer precision into 1, 2, or 3D structures. One example is DNA origami that is well suited to serve as a molecularly defined “breadboard”, and thus, to organize various nanomaterials such as nanoparticles into hybrid systems. Since the controlled assembly of quantum dots...
Biological responses of cells and organisms to nanoparticle exposure crucially depend on the properties of the protein adsorption layer (“protein corona”) forming on nanoparticle surfaces and their characterization is a crucial step toward a deep, mechanistic understanding of their build‐up. Previously, adsorption of one type of model protein on nanoparticles was systematically studied in situ by...
Rational design and development of new‐generation photocatalysts with high hydrogen evolution activity is recognized as an effective strategy to settle energy crisis. To this regard, hybrid photocatalysts of Au quantum dots embedded in rimous cadmium sulfide nanospheres are synthesized by using a simple hydrothermal process followed by photoreduction. The rimous cadmium sulfide nanospheres with rough...
A robust solution phase ligand exchange system for lead sulfide (PbS) quantum dots (QDs) in the presence of Pb‐thiolate ligands is presented that can better preserve the excitonic absorption and emission features as compared to the conventional ligands. The photoluminescence after ligand exchange of PbS QDs with Pb‐thiolate ligand is preserved up to 78% of the original oleate capped PbS QDs.
Tungsten oxide (WO3−x), a new alternative to conventional semiconductor material, has attracted numerous attentions owning to its widespread potential applications. Various methods have been reported for the synthesis of WO3−x nanostructures such as nanowires or nanodots. However, templates or surfactants are often required for the synthesis, which significantly complicate the process and hinder the...
A strategy is reported for the controlled assembly of organic‐inorganic heterostructures consisting of individual single‐walled carbon nanotubes (SWCNTs) selectively coupled to single semiconductor quantum dots (QDs). The assembly in aqueous solution was controlled towards the formation of monofunctionalized SWCNT‐QD structures. Photoluminescence studies in solution, and on surfaces at the single...
A novel architecture made of a CsPbX3/ZnS quantum dot heterostructure is reported, by Xiaosheng Tang, Miao Zhou, and co‐workers in article number 1604085, by combining material synthesis, characterization, optical measurements and density functional theory based first‐principles calculations. This architecture presents high crystal quality, enhanced structural stability and tunable optoelectronic...
The power conversion efficiency of colloidal PbS‐quantum‐dot (QD)‐based solar cells is significantly hampered by lower‐than‐expected open circuit voltage (VOC). The VOC deficit is considerably higher in QD‐based solar cells compared to other types of existing solar cells due to in‐gap trap‐induced bulk recombination of photogenerated carriers. Here, this study reports a ligand exchange procedure based...
All‐inorganic perovskite CsPbX3 (X = Cl, Br, I) and related materials are promising candidates for potential solar cells, light emitting diodes, and photodetectors. Here, a novel architecture made of CsPbX3/ZnS quantum dot heterodimers synthesized via a facile solution‐phase process is reported. Microscopic measurements show that CsPbX3/ZnS heterodimer has high crystalline quality with enhanced chemical...
Multiplexed photoluminescence (PL) detection plays an important role in chemical and biological sensing. Here, it is shown that time‐gated (TG) detection of a single terbium‐donor‐based Förster resonance energy transfer (FRET) pair can be used to selectively quantify low nanomolar concentrations of multiple DNAs or microRNAs in a single sample. This study demonstrates the applicability of single‐TG‐FRET‐pair...
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