There is an urgent need for highly efficient sorbents capable of selectively removing

In this study, we report structural, vibrational, and magnetic data providing evidence of random ion displacement in the core CdSe quantum dots on Cd(2+) sites by Co(2+) ions (between x = 0 0.30). Structural for doping is obtained analyzing powder X-ray diffraction (pXRD), which exhibits a linear lattice compression with increasing concentration, accord Vegard's law. Correlated pXRD shift, hardening longitudinal optical phonon mode new local vibrational are observed track concentration....

The electronic structure of ${\mathrm{TiO}}_{2}$ aerogels is studied by soft x-ray absorption near-edge (XANES) spectroscopy. High-resolution O K-edge and Ti ${L}_{2,3}$-edge XANES spectra are compared with those rutile, anatase, unrelaxed amorphous phases full-density ${\mathrm{TiO}}_{2}.$ Results show that all the main spectroscopic features aerogels, reflecting element-specific partial density empty states correlation effects, can be attributed to absence long-range order in...

The exciton binding energy (EBE) in CdSe quantum dots (QDs) has been determined using X-ray spectroscopy. Using absorption and photoemission spectroscopy, the conduction band (CB) valence (VB) edge shifts as a function of particle size have combined to obtain true gap QDs (i.e., without an exciton). These values can be compared excitonic obtained optical spectroscopy determine EBE. experimental EBE results are with theoretical calculations on show excellent agreement.

The introduction of dopants plays a key role in the physical properties semiconductors for optoelectronic applications. However, doping is generally challenging nanocrystals (NCs), especially two-dimensional (2D) NCs, due to self-annealing effect and high surface energies required dopant addition. Here, we report an efficient strategy Mn-doped 2D CsPbCl3 (i.e., Mn:CsPbCl3) nanoplatelets (NPLs) through postsynthetic solvothermal process. While original lightly doped Mn:CsPbCl3 NPLs were...

To offset the environmental impact of platinum-group element (PGE) mining, recycling techniques are being explored. Porous organic polymers (POPs) have shown significant promise owing to their selectivity and ability withstand harsh conditions. A series pyridine-based POP nanotraps, POP-Py, POP-pNH2 -Py, POP-oNH2 been designed systematically explored for capture palladium, one most utilized PGEs. All nanotraps demonstrated record uptakes rapid capture, with amino group be vital in improving...

The local structure and composition of Cu ions dispersed in CdSe nanocrystals is examined using soft X-ray absorption near edge spectroscopy (XANES). Using L-edge XANES photoelectron measurements (XPS), we find that the exist Cu(I) oxidation state. We also observed signal directly proportional to molar percent present our final material. Se indicates changes density states with doping, due a chemical bonding effect, supports statistical doping mechanism. Photoluminescence (PL) indicate may...

The ability to dope transition-metal ions into semiconductor nanocrystals (NCs) allows for the introduction and exploitation of new extrinsic properties in original intrinsic material. Although synthesis doped zero-dimensional quantum dots one-dimensional nanorods/nanowires has been widely reported, ion-doped two-dimensional (2D) NCs have less explored. In this study, we developed a one-pot Mn2+-doped 2D CdS (i.e., Mn:CdS) nanoplatelets (NPLs). Successful Mn doping inside NPL lattice was...

Abstract All‐inorganic lead halide perovskite nanocrystals (NCs) have great optoelectronic properties with promising applications in light‐emitting diodes (LEDs), lasers, photodetectors, solar cells, and photocatalysis. However, the intrinsic toxicity of Pb instability NCs impede their broad applications. Shell‐coating is an effective method for enhanced environmental stability while reducing by choosing non‐toxic shell materials such as metal oxides, polymers, silica, etc. multiple can be...

Compressive and tensile stress in colloidal CdSe quantum dots (QDs) is examined using resonance Raman spectroscopy. We find that the dispersion of longitudinal optical phonon mode with size does not follow theoretical calculations based on confinement models. To account for these deviations, presence compressive or QDs proposed. The influence surface reconstruction QD behavior evidenced by differences hexadecylamine (HDA) trioctylphospine oxide (TOP/TOPO) passivation. passivated HDA exhibit...

Formation of biomineral structures is increasingly attributed to directed growth a mineral phase from an amorphous precursor on organic matrix. While many in vitro studies have used calcite formation organothiol self-assembled monolayers (SAMs) as model system investigate this process, they generally focused the stability calcium carbonate (ACC) or maximizing control over order final phase. Little known about early stages formation, particularly structural evolution SAM and mineral. Here we...

The detailed mechanism by which ethylene polymerization is initiated the inorganic Phillips catalyst (Cr/SiO2) without recourse to an alkylating cocatalyst remains one of great unsolved mysteries heterogeneous catalysis. Generation active starts with reduction CrVI ions dispersed on silica. A lower oxidation state, generally accepted be CrII, required activate form organoCr site. In this work, a mesoporous, optically transparent monolith CrVI/SiO2 was prepared using sol–gel chemistry in...

This paper describes the synthesis of Eu(III)-doped ZnB2O4 (B = Al(III) or Ga(III)) nanospinels with Eu(III) concentrations varying between 1% and 15.6%. The was achieved through a microwave (MW) synthetic methodology producing 3 nm particles by thermal decomposition zinc undecylenate (UND) metal 2,4-pentanedionate (B(acac)3, B Al3+ Ga3+) in oleylamine (OAm). were then ligand exchanged β-diketonate, 2-thenoyltrifluoroacetone (tta). Using tta as on surface resulted soluble materials that...

All-inorganic metal halide perovskites (ABX3, X = Cl, Br, or I) show great potential for the fabrication of optoelectronic devices, but toxicity and instability lead-based limit their applications. Shell passivation with a more stable lead-free perovskite is promising strategy to isolate unstable components from environment as well feasible way tune optical properties. However, it challenging grow core/shell nanocrystals (NCs) due soft ionic nature lattice. In this work, we developed facile...

Condensed-phase hydrogen-terminated diamond clusters (diamondoids) have been studied with soft-x-ray emission and x-ray-absorption spectroscopy. The occupied unoccupied electronic states measured these methods imply an increasing highest molecular orbital--lowest orbital gap decreasing diamondoid size, the shifting entirely in states, contrast to other semiconductor nanocrystals. These experimental results are compared theoretical calculations on structure of diamondoids.

A quantum dot (QD) contains a well-defined surface passivated by ligands and bulklike core. The effect of passivation lattice truncation on local structural electronic microenvironments within CdSe QD is an area active research. Selectively probing the that exist at core difficult but can be achieved use Mn(II) impurity ion doped into using electron paramagnetic resonance (EPR). By high frequency EPR (HF-EPR) spectroscopy, site-dependent perturbation experienced for incorporated as guest QDs...

Thioctic acid (α-lipoic acid) is a molecule with large disulfide-containing base, short alkyl chain four CH2 units, and carboxyl termination. Self-assembled monolayer (SAM) films of thioctic adsorbed on Au(111) have been investigated near-edge X-ray absorption fine structure (NEXAFS) spectroscopy photoelectron (XPS) to determine film quality, bonding, morphology. Using standard preparation protocols for SAMs, that is, dissolving in ethanol exposing gold the solution, results poor films....

X-ray absorption spectroscopy has been used to characterize the evolution in conduction band (CB) density of states CdSe quantum dots (QDs) as a function particle size. We have unambiguously witnessed QD CB minimum (CBM) shift higher energy with decreasing size, consistent confinement effects, and directly compared our results recent theoretical calculations. At smallest evidence for pinning CBM is presented. Our observations can be explained by considering size-dependent change...

We report evidence that paramagnetism in CdSe QDs can be induced via manipulation of the surface chemistry. Using SQUID magnetometry and X-ray absorption spectroscopy, we demonstrate paramagnetic behavior varied by changing ligand end-group functionality passivating layer. Contrary to previous reports, no for ferromagnetism was observed. The results suggest is π back-bonding between Cd 4d orbtials ligands with empty π* orbitals.

There currently exists much debate as to the active state related "long afterglow" effect in europium doped oxide materials. Redox couples that consist of Eu(+/2+) and Eu(2+/3+) are discussed, but no common answer is accepted. Here, we present a comparison optical properties commercially available SrAl(2)O(4):Eu, Dy phosphor, function nanoparticle size reduction via dry mechanical milling. X-ray spectroscopic data indicate significant decrease phosphorescence efficiency an increase laser...

Open AccessCCS ChemistryRESEARCH ARTICLE1 May 2021CrN-Encapsulated Hollow Cr-N-C Capsules Boosting Oxygen Reduction Catalysis in PEMFC Hui Yang, Xu Wang, Tao Zheng, Nelly Cantillo Cuello, Gabriel Goenaga, Thomas A. Zawodzinski, He Tian, Joshua T. Wright, Robert W. Meulenberg, Xiangke Zhenhai Xia and Shengqian Ma Yang College of Environmental Science Engineering, North China Electric Power University, Beijing 102206 , Wang State Key Laboratory Silicon Materials, Center Electron Microscopy,...

Abstract In terms of producing new advances in sustainable nanomaterials, cation exchange (CE) post-processed colloidal nanocrystals (NCs) has opened avenues towards non-toxic energy materials via simple chemical techniques. The main processes governing CE can be explained by considering hard/soft acid/base theory, but the detailed mechanism CE, however, been debated and attributed to both diffusion vacancy processes. this work, we have performed situ x-ray absorption spectroscopy further...

Use of Chatt metal-arene protocols with uranium leads to the synthesis first well-characterized, unsupported actinide–arenide sandwich complexes. The electronic structures actinide centres show a key sensitivity ion pairing effects.