Retraction: Phosphorus-Rich Colloidal Cobalt Diphosphide (CoP ) Nanocrystals for Electrochemical and Photoelectrochemical Hydrogen Evolution.

Adv. Mater. 2019, 31, 1900813.

Retraction: Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc-Air Battery.

Adv. Mater. 2018, 30, 1705796 https://doi.

Correction: Synthesis of lead-free CsSbBr perovskite alternative nanocrystals with enhanced photocatalytic CO reduction activity.

Correction for 'Synthesis of lead-free CsSbBr perovskite alternative nanocrystals with enhanced photocatalytic CO reduction activity' by Chang Lu , , 2020, , 2987-2991, https://doi.org/10.1039/C9NR07722G.

Facet-Selective Deposition of Ultrathin Al O on Copper Nanocrystals for Highly Stable CO Electroreduction to Ethylene.

Catalysts based on Cu nanocrystals (NCs) for electrochemical CO -to-C conversion with high activity have been a subject of considerable interest, but poor stability and low selectivity for a single C product remain obstacles for realizing sustainable carbon-neutral cycles. Here, we used the facet-selective atomic layer deposition (FS-ALD) technique to selectively cover the (111) surface of Cu NCs with ultrathin Al O to increase the exposed facet ratio of (100)/(111), resulting in a faradaic efficiency ratio of C H /CH for overcoated Cu NCs 22 times higher than that for pure Cu NCs. Peak performance of the overcoated catalyst (Cu NCs/Al O -10C) reaches a C H faradaic efficiency of 60.

Scalable neutral HO electrosynthesis by platinum diphosphide nanocrystals by regulating oxygen reduction reaction pathways.

Despite progress in small scale electrocatalytic production of hydrogen peroxide (HO) using a rotating ring-disk electrode, further work is needed to develop a non-toxic, selective, and stable O-to-HO electrocatalyst for realizing continuous on-site production of neutral hydrogen peroxide. We report ultrasmall and monodisperse colloidal PtP nanocrystals that achieve HO production at near zero-overpotential with near unity HO selectivity at 0.27 V vs.

Synthesis of lead-free CsSbBr perovskite alternative nanocrystals with enhanced photocatalytic CO reduction activity.

A synthetic method for uniform and pure Cs3Sb2Br9 NCs has been developed. Cs3Sb2Br9 NCs exhibit a 10-fold increase in activity for the photocatalytic CO2 reduction reaction compared to CsPbBr3 NCs, achieving 510 μmol CO g-1 cat. after 4 h.

Colloidal silver diphosphide (AgP) nanocrystals as low overpotential catalysts for CO reduction to tunable syngas.

Production of syngas with tunable CO/H ratio from renewable resources is an ideal way to provide a carbon-neutral feedstock for liquid fuel production. Ag is a benchmark electrocatalysts for CO-to-CO conversion but high overpotential limits the efficiency. We synthesize AgP nanocrystals (NCs) with a greater than 3-fold reduction in overpotential for electrochemical CO-to-CO reduction compared to Ag and greatly enhanced stability.

Impact of Nb(V) Substitution on the Structure and Optical and Photoelectrochemical Properties of the Cu(TaNb )O Solid Solution.

A family of solid solutions, Cu(TaNb )O (0 ≤ x ≤ 0.4), was investigated as p-type semiconductors for their band gaps and energies and for their activity for the reduction of water to molecular hydrogen. Compositions from 0 to 40 mol % niobium were prepared in high purity by solid-state methods, accompanied by only very small increases in the lattice parameters of ∼0.

Phosphorus-Rich Colloidal Cobalt Diphosphide (CoP ) Nanocrystals for Electrochemical and Photoelectrochemical Hydrogen Evolution.

Developing earth-abundant and efficient electrocatalysts for photoelectrochemical water splitting is critical to realizing a high-performance solar-to-hydrogen energy conversion process. Herein, phosphorus-rich colloidal cobalt diphosphide nanocrystals (CoP NCs) are synthesized via hot injection. The CoP NCs show a Pt-like hydrogen evolution reaction (HER) electrocatalytic activity in acidic solution with a small overpotential of 39 mV to achieve -10 mA cm and a very low Tafel slope of 32 mV dec .

Molecular Rectifiers on Silicon: High Performance by Enhancing Top-Electrode/Molecule Coupling.

One of the simplest molecular-scale electronic devices is the molecular rectifier. In spite of considerable efforts aimed at understanding structure-property relationships in these systems, devices with predictable and stable electronic properties are yet to be developed. Here, we demonstrate highly efficient current rectification in a new class of compounds that form self-assembled monolayers on silicon.

Interface Engineering of Colloidal CdSe Quantum Dot Thin Films as Acid-Stable Photocathodes for Solar-Driven Hydrogen Evolution.

Colloidal semiconductor quantum dot (CQD)-based photocathodes for solar-driven hydrogen evolution have attracted significant attention because of their tunable size, nanostructured morphology, crystalline orientation, and band gap. Here, we report a thin film heterojunction photocathode composed of organic PEDOT:PSS as a hole transport layer, CdSe CQDs as a semiconductor light absorber, and conformal Pt layer deposited by atomic layer deposition (ALD) serving as both a passivation layer and cocatalyst for hydrogen evolution. In neutral aqueous solution, a PEDOT:PSS/CdSe/Pt heterogeneous photocathode with 200 cycles of ALD Pt produces a photocurrent density of -1.

Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc-Air Battery.

Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this work, highly monodisperse CoP and Co P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co P NCs show higher OER performance owing to easier formation of plentiful Co P@COOH heterojunctions.

An atomic layer deposition chamber for in situ x-ray diffraction and scattering analysis.

The crystal structure of thin films grown by atomic layer deposition (ALD) will determine important performance properties such as conductivity, breakdown voltage, and catalytic activity. We report the design of an atomic layer deposition chamber for in situ x-ray analysis that can be used to monitor changes to the crystal structural during ALD. The application of the chamber is demonstrated for Pt ALD on amorphous SiO2 and SrTiO3 (001) using synchrotron-based high resolution x-ray diffraction, grazing incidence x-ray diffraction, and grazing incidence small angle scattering.

In Vacuo Photoemission Studies of Platinum Atomic Layer Deposition Using Synchrotron Radiation.

The mechanism of platinum atomic layer deposition using (methylcyclopentadienyl)trimethylplatinum and oxygen is investigated with in vacuo photoemission spectroscopy at the Stanford Synchrotron Radiation Lightsource. With this surface-sensitive technique, the surface species following the Pt precursor half cycle and the oxygen counter-reactant half cycle can be directly measured. We observed significant amounts of carbonaceous species following the Pt precursor pulse, consistent with dehydrogenation of the precursor ligands.

Electroluminescence from nanoscale materials via field-driven ionization.

The high degree of morphological and energetic disorder inherent to many nanosized materials places limitations on charge injection into and transport rates through thin films of these materials. We demonstrate electroluminescence achieved by local generation of charge that eliminates the need for injection of charge carriers from the device electrodes. We show electroluminescence from thin films of nanoscale materials that do not support direct current excitation and suggest a mechanism for the charge generation and electroluminescence that is consistent with our time-averaged and time-resolved observations.

Efficient luminescent down-shifting detectors based on colloidal quantum dots for dual-band detection applications.

A colloidal quantum dot (QD) luminescent down-shifting (LDS) layer is used to sensitize an InGaAs short wavelength infrared photodetector to the near UV spectral band. An average improvement in the external quantum efficiency (EQE) from 1.8% to 21% across the near UV is realized using an LDS layer consisting of PbS/CdS core/shell QDs embedded in PMMA.

Perspective on the prospects of a carrier multiplication nanocrystal solar cell.

This article presents a perspective on the experimental and theoretical work to date on the efficiency of carrier multiplication (CM) in colloidal semiconductor nanocrystals (NCs). Early reports on CM in NCs suggested large CM efficiency enhancements. However, recent experiments have shown that CM in nanocrystalline samples is not significantly stronger, and often is weaker, than in the parent bulk when compared on an absolute photon energy basis.

Control of the carrier type in InAs nanocrystal films by predeposition incorporation of Cd.

Nanocrystal (NC) films have been proposed as an alternative to bulk semiconductors for electronic applications such as solar cells and photodetectors. One outstanding challenge in NC electronics is to robustly control the carrier type to create stable p-n homojunction-based devices. We demonstrate that the postsynthetic addition of Cd to InAs nanocrystals switches the resulting InAs:Cd NC films from n-type to p-type when operating in a field effect transistor.

Colloidal PbS quantum dot solar cells with high fill factor.

We fabricate PbS colloidal quantum dot (QD)-based solar cells using a fullerene derivative as the electron-transporting layer (ETL). A thiol treatment and oxidation process are used to modify the morphology and electronic structure of the QD films, resulting in devices that exhibit a fill factor (FF) as high as 62%. We also show that, for QDs with a band gap of less than 1 eV, an open-circuit voltage (VOC) of 0.

A broadband Fourier transform microwave spectrometer based on chirped pulse excitation.

Designs for a broadband chirped pulse Fourier transform microwave (CP-FTMW) spectrometer are presented. The spectrometer is capable of measuring the 7-18 GHz region of a rotational spectrum in a single data acquisition. One design uses a 4.

The use of size-selective excitation to study photocurrent through junctions containing single-size and multi-size arrays of colloidal CdSe quantum dots.

This paper describes a study of the generation and flow of photocurrent through junctions containing three-dimensional arrays of colloidal CdSe quantum dots (QDs) of either a single size or multiple sizes. The electrodes were indium tin oxide (ITO) covered with a thin layer of poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) and a eutectic alloy of Ga and In (EGaIn). We measured the current-voltage characteristics of the junctions in the dark and under illumination, with various sources and wavelengths of excitation, and their photocurrent action spectra.

Size-dependent charge collection in junctions containing single-size and multi-size arrays of colloidal CdSe quantum dots.

This paper describes the electrical characteristics of junctions composed of three-dimensional arrays of colloidal CdSe quantum dots (QDs) with tin-doped indium oxide (ITO)/poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) and eutectic Ga-In (EGaIn) electrodes. It focuses on a comparison of junctions containing QDs of one size to those of arrays containing QDs of multiple sizes. This comparison makes it possible to estimate the relative contributions of transport across various interfaces (e.