Amy L Prieto

• Professor (Associate) at Colorado State University

There is an urgent need for improved energy storage devices to enable advances in markets ranging from small-scale applications (such as portable electronic devices) to large-scale energy storage for transportation and electric-grid energy. Next-generation batteries must be characterized by high energy density, high power density, fast charging cap...

The widescale adaption of intermittent renewable energy sources, such as wind and solar, must be accompanied by a grid storage network to store energy when it is abundant and redistribute it as needed for on-demand use. Short-term storage in the form of rechargeable batteries is an attractive avenue for meeting these storage needs. The dominant tec...

The family of copper antimony selenides is important for renewable energy applications. Several phases are accessible within narrow energy and compositional ranges, and tunability between phases is not well-established. Thus, this system provides a rich landscape to understand the phase transformations that occur in hot-injection nanoparticle synth...

Alloy-based materials such as antimony (Sb) are of interest for both Li/Na-ion batteries due to their theoretical capacity and electronic conductivity. Of the various ways to fabricate Sb films (slurry casting, sputtering, etc.) one promising route is through the use of electrodeposition. Electrodeposition is an industrially relevant synthetic tech...

Alloy-type anodes, such as metallic antimony, demonstrate promise as alternative electrode materials for lithium-ion battery systems due to their high theoretical capacity of 660 mAh/g. However, antimony undergoes anisotropic volume expansion and multiple crystallographic phase transformations upon lithiation and delithiation, which often leads to...

Antimony (Sb) electrodes are an ideal anode material for sodium-ion batteries, which are an attractive energy storage system to support grid-level energy storage. These anodes have high thermal stability, good rate performance, and good electronic conductivity, but there are limitations on the fundamental understanding of phases present as the mate...

Testing sodium battery technology relies on a half-cell setup with sodium metal as the counter electrode. Herein, we show that sodium metal reacts with conventional carbonate electrolyte to form the...

The solid electrolyte interface (SEI) forms from electrolyte decomposition during the initial discharge of half-cell batteries and is affected by the presence of electrolyte additives. Breaking down the initial discharge into stages, defined by voltage cut offs, can help discover the role of additives in SEI growth. In this study, X-Ray Photoelectr...

As the number of markets, as well as the overall market size, for rechargeable batteries continues to grow, it is clear that there is no one perfect battery to suit every application. In the best case, we would have batteries that store a very large amount of energy per unit mass or volume (energy density), can charge and discharge very quickly (po...

Electrolyte additives such as vinylene carbonate (VC) have been demonstrated to improve the capacity retention for many types of Li-ion battery electrodes, including intermetallic alloying anodes, but it is still unclear why VC extends the cycle lifetime of copper antimonide (Cu2Sb) anodes so dramatically. Here, we have studied how VC affects the s...

Olivine Fe2GeS4 has been identified as a promising photovoltaic absorber material introduced as an alternate candidate to iron pyrite, FeS2. The compounds share similar benefits in terms of elemental abundance and relative non-toxicity, but Fe2GeS4 was predicted to have higher stability with respect to decomposition to alternate phases and, therefo...

The first colloidal nanoparticle synthesis of the copper selenophosphate Cu3PSe4, a promising new material for photovoltaics, is reported. Because the formation of binary copper selenide impurities seemed to form more readily, two approaches were developed to install phosphorus bonds directly: 1) the synthesis of molecular P4Se3 and subsequent reac...

Kolloidale Nanopartikelsynthese: Cu3PSe4‐Nanopartikel wurden in der Lösungsphase durch Selenierung von isolierten und gereinigten Cu3P‐Nanopartikeln synthetisiert. Abstract The first colloidal nanoparticle synthesis of the copper selenophosphate Cu3PSe4, a promising new material for photovoltaics, is reported. Because the formation of binary coppe...

Antimony is a known high capacity anode material for both Li- and Na-ion batteries that has the potential to improve the energy storage density over commercial graphite anode-based Li-ion batteries. As with other high capacity anode materials (such as silicon), the large storage capacity of antimony results in large volume changes of the anode duri...

The last fifty years of solid-state chemistry have produced a wealth of compounds with complex structures, exciting properties, and from those discoveries, an explosion of new technologies. We continue to strive to understand structure-property relationships as well as develop expedient methods to discover and control new materials. Nanoparticle sy...

Electrodeposited Cu-Sb thin films on Cu and Ni substrates are investigated as alloy anodes for Li-ion batteries to elucidate the effects of both the film composition and substrate interactions on anode cycling stability and lifetime. Thin films of composition CuxSb (0<x<2) exhibit the longest cycle lifetimes nearest x=1. Additionally, the Cu-Sb fil...

Photovoltaic (PV) devices based on bulk polycrystalline Cu2ZnSn(S1-ySey)4 (CZTSSe) as the absorber material have historically shown the best efficiency with high Se compositions. The selenization process, which is employed in the formation of absorber layer, has been shown to result in maximum device efficiency at a lower than predicted optimal ban...

The efficient conversion of optical laser light into bright ultrafast x-ray pulses in laser created plasmas is of high interest for dense plasma physics studies, material science, and other fields. However, the rapid hydrodynamic expansion that cools hot plasmas has limited the x-ray conversion efficiency (CE) to 1% or less. Here we demonstrate mor...

Nanocrystal (NC) Cu₂ZnSnS₄ (CZTS) solar cells, composed of a non-toxic and earth abundant absorber material, have great potential in low-cost solar energy harvesting. However, CZTS NC films typically must be thermally annealed at elevated temperatures and under harsh environments in order to produce high efficiency devices. Th...

Nanowires of electrochemically active electrode materials for lithium ion batteries represent a unique system that allows for intensive investigations of surface phenomena. In particular, highly ordered nanowire arrays produced by electrodeposition into anodic aluminum oxide templates can lead to new insight into a materials electrochemical perform...

Electrodeposited crystalline Cu2Sb thin films are studied to evaluate the use of these electrodes as model systems for studying Cu2Sb as a lithium ion battery anode material. The films have been characterized with an emphasis on determining the film quality and relating the structure, composition, and morphology to the resulting electrochemical and...

Poor charge transport in Cu2ZnSnS4 (CZTS) nanocrystal (NC) thin films presents a great challenge in the fabrication of solar cells without post-annealing treatments. We introduce a novel approach to facilitate the charge carrier hoping between CZTS NCs by growing a stoichiometric Cu2Se shell that can be oxidized to form a conductive Cu2-xSe phase w...

An apparatus and method for measuring the isoelectric pH for materials deposited on or otherwise affixed onto and in contact with an electrode surface, and a method for utilizing the isoelectric pH to form nanometer thickness, self-assembled layers on the material, are described. Forming such layers utilizing information obtained about the isoelect...

We report the electrodeposition of zinc-antimony composite films from aqueous solution. We show that it is possible to produce Zn4Sb3 films on zinc substrates by low temperature annealing and we evaluate their performance as sodium-ion battery anodes. Near complete utilization of the antimony during cycling, good capacity retention, and high rate p...

A thorough structure determination has been performed on Cu2ZnSnS4 nanoparticles, a popular photovoltaic material, using neutron diffraction—to characterize the long-range average crystal structure—and X-ray absorption fine structure (XAFS) spectroscopy at the Cu, Zn, and Sn K-edges to elucidate the element-specific local structure. This is the fir...

The coating of three-dimensional nanostructured electrodes is a significant challenge for the future of many energy storage devices and, if successful, could profoundly increase battery power. The synthesis of a new class of monomers that can be electrochemically polymerized is a key first step in affording a conformally coated, nanoscale lithium-i...

A lithium-ion battery having an anode including an array of nanowires electrochemically coated with a polymer electrolyte, and surrounded by a cathode matrix, forming thereby interpenetrating electrodes, wherein the diffusion length of the Li.sup.+ ions is significantly decreased, leading to faster charging/discharging, greater reversibility, and l...

Hydrogen is an attractive fuel for many applications because of its high energy density as molecular hydrogen, as well as the clean exhaust produced when burned with oxygen. One significant challenge to the widespread adoption of hydrogen, for mobile applications in particular, is the inability to efficiently store large amounts of readily accessib...

We have demonstrated the volumetric heating of near-solid density plasmas to keV temperatures using ultra-high contrast femtosecond laser pulses of only 0.5 J energy to irradiate arrays of vertically aligned nanowires (Purvis et al. Nat Photonics 7:796–780, 2013). Our x-ray spectra and particle-in-cell (PIC) simulations show extremely highly ionize...

The objective of this study was to assess the antibacterial activity and inhibition of biofilm formation of silver nanoparticles (AgNPs) against Escherichia coli (MG1655), Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Janthinobacterium lividum. The AgNPs utilized in this study were prepared through one...

Silver nanoparticles (AgNPs) were prepared in a one-step microwave-assisted synthesis guided by the principles of green chemistry. Microwave parameters were optimized using the Box–Benhken design for three factors (time, temperature, and pressure). Aqueous extracts from the peels of citrus fruits (orange, grapefruit, tangelo, lemon, and lime) were...

Iron chalcogenides, in particular iron pyrite, have great potential to be useful materials for cost effective thin film photovoltaics. However, the performance of pyrite as an absorber material in a photovoltaic device has fallen far short of the theoretical efficiency. A potential cause of this may be the instability of the pyrite phase. An altern...

The heating of dense matter to extreme temperatures motivates the development of powerful lasers1, 2, 3, 4. However, the barrier the critical electron density imposes to light penetration into ionized materials results in the deposition of most of the laser energy into a thin surface layer at typically only 0.1% of solid density. Here, we demonstra...

Secondary lithium-ion batteries have found multiple applications in portable electronics where high charge and discharge rates are not required to improve performance. However, lithium-ion batteries are currently being sought for high power applications that require long cycle life, such as those encountered in the transportation sector. To meet th...

Electrodeposition as a Route Toward Fabrication of Three-Dimensional Electrochemical Energy Storage Devices Derek C. Johnson, Matthew T. Rawls, and Amy L. Prieto Chemistry Department, Colorado State University Prieto Battery, Inc., Fort Collins, CO Lithium-ion batteries have become the primary energy choice for low power applications, and a...

Aqueous Based Cathode Slurries For Use in Three-Dimensional Lithium-ion Batteries Derek C. Johnson, Matthew T. Rawls, and Amy L. Prieto Chemistry Department, Colorado State University Prieto Battery, Inc., Fort Collins, CO Traditional two-dimensional planar based lithium-ion batteries have the inherent trade-off between energy and power den...

We are experimentally and theoretically studying the generation of bright x-ray pulses in volumetrically heated plasmas created by intense femtosecond laser pulse irradiation of vertically aligned nanowire arrays. The scheme we utilize allows us to achieve homogeneous volumetric heating of near-solid density targets to simultaneously achieve almost...

A lithium-ion battery including an electrodeposited anode material having a micron-scale, three-dimensional porous foam structure separated from interpenetrating cathode material that fills the void space of the porous foam structure by a thin solid-state electrolyte which has been reductively polymerized onto the anode material in a uniform and pi...

Strontium titanate nanoparticles have been synthesized using a combination of sol-precipitation and hydrothermal techniques for subsequent testing as an anode material for lithium-ion batteries. The potentials associated with lithiation are 0.105V and 0.070V vs. Li/Li+ and 0.095V and 0.142V vs. Li/Li+ during de-lithiation. These potentials are sign...

Nanocrystals of multicomponent chalcogenides, such as Cu(2)ZnSnS(4) (CZTS), are potential building blocks for low-cost thin-film photovoltaics (PVs). CZTS PV devices with modest efficiencies have been realized through postdeposition annealing at high temperatures in Se vapor. However, little is known about the precise role of Se in the CZTS system....

Three-dimensional (3D) battery architectures have emerged as a new direction for powering microelectromechanical systems and other small autonomous devices. Although there are few examples to date of fully functioning 3D batteries, these power sources have the potential to achieve high power density and high energy density in a small footprint. Thi...

Mg nanocrystals of controllable sizes were prepared in gram quantities by chemical reduction of magnesocene using a reducing solution of potassium with an aromatic hydrocarbon (either biphenyl, phenanthrene, or naphthalene). The hydrogen sorption kinetics were shown to be dramatically faster for nanocrystals with smaller diameters, although the act...

An apparatus and method for measuring the isoelectric pH for materials deposited on or otherwise affixed onto and in contact with an electrode surface, and a method for utilizing the isoelectric pH to form nanometer thickness, self-assembled layers on the material, are described. Forming such layers utilizing information obtained about the isoelect...

Cu2ZnSnS4 (CZTS) nanocrystals, synthesized by a hot injection solution method, have been fabricated into thin films by dip-casting onto fluorine doped tin oxide (FTO) substrates. The photoresponse of the CZTS nanocrystal films was evaluated using absorbance measurements along with photoelectrochemical methods in aqueous electrolytes. Photoelectroch...

Ternary copper ferrite and copper cobalt ferrite nanotubes were deposited via a chemical vapor deposition process utilizing decomposing solid precursors under oxygen flow into anodic aluminum oxide templates heated to 450 °C. Extracted nanotubes were subsequently calcined at 450 °C for 12 h. Transmission electron microscopy, selected-area electron...

Stoichiometric copper(I) selenide nanoparticles have been synthesized using the hot injection method. The effects of air exposure on the surface composition, crystal structure, and electronic properties were monitored using X-ray photoelectron spectroscopy, X-ray diffraction, and conductivity measurements. The current-voltage response changes from...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chemical vapor deposition (CVD) with vapor-liquid-solid (VLS) growth is employed to synthesize individual Ge(2)Sb(2)Te(5) nanowires with the ultimate goal of synthesizing a large scale nanowire array for universal memory storage. A consistent challenge encountered during the synthesis is a lack of control over the composition and morphology across...

Here we report the in situ doping of Sinanowires with Cu, which results in nanowires containing nanocrystalline inclusions of Cu3Si and significantly enhanced electrical conductivity. These nanowires are of interest for use in secondary Li batteries as well as nanowire arrays that can be directly sensitized for photovoltaic applications. This synth...

Cu(2)Sb was electrodeposited onto transmission electron microscopy (TEM) grids to investigate changes in morphology, composition, and crystal structure during the early stages of nucleation and growth. Multiple transitions were observed within the first second of the deposition, leading to the formation of crystalline Cu(2)Sb. These transitions wer...

Recent advances have been made in thin-film solar cells using CdTe and CuIn(1-x)Ga(x)Se(2) (CIGS) nanoparticles, which have achieved impressive efficiencies. Despite these efficiencies, CdTe and CIGS are not amenable to large-scale production because of the cost and scarcity of Te, In, and Ga. Cu(2)ZnSnS(4) (CZTS), however, is an emerging solar cel...

We describe the direct single potential electrodeposition of crystalline Cu2Sb, a promising anode material for lithium-ion batteries, from aqueous solutions at room temperature. The use of citric acid as a complexing agent increases the solubility of antimony salts and shifts the reduction potentials of copper and antimony toward each other, enabli...

Protein phosphorylation serves as a critical biochemical regulator of short-term and long-term synaptic plasticity. Receptor protein tyrosine kinases (RPTKs) including members of the trk, eph and erbB subfamilies have been shown to modulate signaling cascades that influence synaptic function in the central nervous system (CNS). Tyro3 is one of thre...

The stability of the superconducting dissipationless and resistive states in single-crystalline NbSe2 nanoribbons is characterized by transport measurements in an external magnetic field (H). Current-driven electrical measurements show voltage steps, indicating the nucleation of phase-slip structures. Well below the critical temperature, the positi...

The stability of the superconducting dissipationless and resistive states in single-crystalline NbSe2 nanobelts is characterized by transport measurements in an external magnetic field (H). Current-driven electrical measurements show voltage steps, indicating the nucleation of phase-slip structures. Well below the critical temperature, the position...

Superconducting NbSe2 nanowires have been studied with electrical transport. The cross-sectional dimensions are smaller than the London penetration depth, and signatures of confined magnetic vortices have been observed. The critical current shows non-monotonic behavior as the external magnetic field is increased, including periodic features corresp...

We report the synthesis of single-crystalline VO2 nanowires with rectangular cross sections using a vapor transport method. These nanowires have typical diameters of 60 (+/-30) nm and lengths up to >10 mum. Electron microscopy and diffraction measurements show that the VO2 nanowires are single crystalline and exhibit a monoclinic structure. Moreove...

Bismuth telluride nanowires are of interest for thermoelectric applications because of the predicted enhancement in the thermoelectric figure-of-merit in nanowire structures. In this letter, we carried out temperature-dependent thermal diffusivity characterization of a 40 nm diameter Bi ₂ Te ₃ nanowires/alumina nanocomposite....

We report a simple and reproducible method to fabricate two metallic electrodes made of different metals with a nanometer-sized gap. These electrodes are fabricated by defining a pair of gold electrodes lithographically and electrodepositing a second metal onto one of them. The method enables the fabrication of pairs of metallic electrodes that exh...

Films and 200-nm wire arrays of Bi 1-x Sb x alloys, one of the best known low-temperature thermoelectric materials, have been obtained by electrodeposition without the need for complexing the Sb cations in solution or further thermal treatment after deposition. The process consists of reduction of Bi 1-x Sb x directly from a solution of Bi(NO 3) 3...

Arrays of 40 nm Bi2-xSbxTe3 nanowires (x similar to 0.7, density similar to5 x 10(10) cm(-2)) have been synthesized. The individual wires are crystalline, relatively homogeneous, and highly textured in a <110> direction after thermal treatment. Wires containing Sb exhibit incomplete wetting of the alumina templates in which they are grown (see Figu...

Films and arrays of 200 and 50 nm diameter wires of Bi2Te3-xSex have been electrodeposited in the following general reaction: 2Bi3+ + (3−y)HTeO2+ + (y)H2SeO3 + (9+y)H+ + 18e- → Bi2Te3-ySey + (6+y)H2O. Films produced from an electrolyte of 0.0075 M Bi, 0.0090 M Te, and 0.0010 M Se in 1 M HNO3 at a potential of 0 V vs Ag/AgCl are single phase with co...

Here we report the synthesis of dense arrays of Bi1-xSbx nanowires with >5 x 1010 nanowires/cm2. The individual wires are crystalline, relatively homogeneous, and highly textured in a 110 direction, with diameters of 40 nm and a composition of x = 12-15 atom % Sb. By tuning the solution concentrations and controlling the growth rate by controlling...

In this paper, the processes associated with the electrodeposition of bismuth telluride (Bi2Te3), a thermoelectric material, are reported along with an analysis of the composition and crystallinity of the resulting films. The electrodeposition can be described by the general reaction 3HTeO2+ + 2Bi3+ + 18e- + 9H+ -> Bi2Te3 + 6H2O. Cyclic voltammetry...

Theoretical predictions suggest that the thermoelectric properties of nanowires could be greatly enhanced compared with the bulk materials. To investigate these predictions, bismuth telluride nanowires are synthesized by electrodeposition into the cavities of porous alumina templates. Individual nanowires are then isolated, and subjected to measure...

The fabrication of high-density, high aspect ratio, large area bismuth telluride nanowire arrays by electrodeposition into porous anodic alumina templates was demonstrated. Wires with average diameter ≅ 45nm and aspect ratio greater than 1000 were prepared. The array-template composites used were thick, and had a high wire density permitting the as...

Narrow Bi2Te3 nanowire arrays, where the individual wires are dense and parallel, have been fabricated by electrodeposition. The array–template composites have a high wire density over a large area (see Figure) and are relatively thick, which makes them ideally suited for direct incorporation into existing device structures for thermoelectric or ot...

In the recent years there has been an increasing interest in low-dimensional thermoelectric materials such as superlattices, quantum dots and nanowires [1,2,3]. An enhancement in thermoelectric figure-of-merit, Z=σα2 /k, where α is the Seebeck coefficient, σ is electrical conductivity, and k is the thermal conductivity, is predicted due to increase...

The function and viability of vertebrate photoreceptors requires the daily phagocytosis of photoreceptor outer segments (OS) by the adjacent retinal pigment epithelium (RPE). We demonstrate here a critical role in this process for Gas6 and by implication one of its receptor protein tyrosine kinases (RTKs), Mertk (Mer). Gas6 specifically and selecti...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Due to effects of reduced dimensionality, Bi2Te3 nanowires are predicted to have increased thermoelectric efficiency relative to bulk Bi2Te3, one of the most efficient thermoelectric materials known. High-density arrays of nanowires have desirable characteristics for accessing nanowire properties in potential applications and also allow for facile...

Widespread applications of thermoelectric materials are limited due to low efficiency. Currently, the most widely used thermoelectric devices consist of alloys based on Bi 2 Te 3 . In such devices, the thermoelectric figure-of-merit (ZT) of bulk Bi 2 Te 3 has been increased through doping. It is postulated that further enhancements in ZT may be att...

Tyro-3, Axl, and Mer are three related receptor protein-tyrosine kinases (RPTKs) characterized by an extracellular domain exhibiting significant amino acid sequence similarity to neural cell adhesion molecules. The molecule Gas6 (for growth arrest-specific gene-6) has been shown to activate each of these receptors. Gas6 is expressed extensively in...

We have employed transmission electron microscopy (TEM) and analytical electron microscopy to perform preliminary assessment of the structure, composition and electronic properties of nanowire arrays at high spatial resolution. The two systems studied were bismuth and bismuth telluride nanowire arrays in alumina (wire diameters ~40nm), both of whic...

Gas6 (growth arrest specific gene-6) is a ligand for members of the Axl subfamily of receptor protein-tyrosine kinases. One of these receptors, Tyro-3, is widely expressed in the central nervous system. We have used biochemical and histological techniques, including in situ hybridization, to determine the expression patterns of Gas6 mRNA and protei...

Materials with the skutterudite crystal structure, such as CoSb ₃, have been demonstrated to be promising in the development of high figure-of-merit thermoelectric materials. Theoretical studies have shown that quantum confinement may produce enhancements in the figure-of-merit. Calculations based on the Kubakaddi model for thermopower o...

The functional units in most inductive and morphogenetic processes in the embryo are not single cells, but rather collectives of interacting cells that give rise to the tissues and organs. Cell adhesion molecules (CAMs) are involved in defining cell collectives and their borders as they interact during inductive events in morphogenesis. The express...