Showing papers by "Ralph G. Nuzzo published in 2019"

Local Structure and Electronic State of Atomically Dispersed Pt Supported on Nanosized CeO2

Abstract: Single atom catalysts (SACs) have shown high activity and selectivity in a growing number of chemical reactions. Many efforts aimed at unveiling the structure-property relationships underpinning th ...

Designing and transforming yield-stress fluids

Abstract: We review progress in designing and transforming multi-functional yield-stress fluids and give a perspective on the current state of knowledge that supports each step in the design process. We focus mainly on the rheological properties that make yield-stress fluids so useful and the trade-offs which need to be considered when working with these materials. Thinking in terms of “design with” and “design of” yield-stress fluids motivates how we can organize our scientific understanding of this field. “Design with” involves identification of rheological property requirements independent of the chemical formulation, e.g. for 3D direct-write printing which needs to accommodate a wide range of chemistry and material structures. “Design of” includes microstructural considerations: conceptual models relating formulation to properties, quantitative models of formulation-structure-property relations, and chemical transformation strategies for converting effective yield-stress fluids to be more useful solid engineering materials. Future research directions are suggested at the intersection of chemistry, soft-matter physics, and material science in the context of our desire to design useful rheologically-complex functional materials.

Ionic Hydrogels with Biomimetic 4D-Printed Mechanical Gradients: Models for Soft-Bodied Aquatic Organisms

Abstract: Direct-ink writing (DIW), a rapidly growing and advancing form of additive manufacturing, provides capacities for on-demand tailoring of materials to meet specific requirements for final designs. T ...

CoS2 as a sulfur redox-active cathode material for high-capacity nonaqueous Zn batteries

Abstract: Nonaqueous Zn-ion batteries are a promising candidate for a high-energy storage system to replace Li-ion batteries. Here, we report on CoS2 as a cathode material for Zn-ion batteries using nonaqueo...

3D-Printed Hydrogel Composites for Predictive Temporal (4D) Cellular Organizations and Patterned Biogenic Mineralization

Abstract: Materials chemistries for hydrogel scaffolds that are capable of programming temporal (4D) attributes of cellular decision-making in supported 3D microcultures are described. The scaffolds are fabricated using direct-ink writing (DIW)-a 3D-printing technique using extrusion to pattern scaffolds at biologically relevant diameters (≤ 100 µm). Herein, DIW is exploited to variously incorporate a rheological nanoclay, Laponite XLG (LAP), into 2-hydroxyethyl methacrylate (HEMA)-based hydrogels-printing the LAP-HEMA (LH) composites as functional modifiers within otherwise unmodified 2D and 3D HEMA microstructures. The nanoclay-modified domains, when tested as thin films, require no activating (e.g., protein) treatments to promote robust growth compliances that direct the spatial attachment of fibroblast (3T3) and preosteoblast (E1) cells, fostering for the latter a capacity to direct long-term osteodifferentiation. Cell-to-gel interfacial morphologies and cellular motility are analyzed with spatial light interference microscopy (SLIM). Through combination of HEMA and LH gels, high-resolution DIW of a nanocomposite ink (UniH) that translates organizationally dynamic attributes seen with 2D gels into dentition-mimetic 3D scaffolds is demonstrated. These analyses confirm that the underlying materials chemistry and geometry of hydrogel nanocomposites are capable of directing cellular attachment and temporal development within 3D microcultures-a useful material system for the 4D patterning of hydrogel scaffolds.

In Situ Strain Measurement in Solid-State Li-Ion Batteries

Abstract: Volumetric changes due to repeated lithiation and delithiation are a significant source of electrode degradation and capacity fade in rechargeable batteries Measurement of such volumetric changes and their resultant electro-chemo-mechanical strains and stresses have previously been investigated in conventional liquid-electrolyte Li-ion batteries In the present study, we propose to extend the current knowledge and measurement techniques into the area of all-solid-state Li-ion batteries Due to the presence of inherent property mismatch as well as confinements imposed at the interfaces between the electrodes and solid electrolyte, solid-state battery components are more prone to interfacial damage and In this work, novel experimental approaches are designed to facilitate in-situ strain measurements on solid electrolytes (SE), electrodes and SE/electrode interface Digital image correlation (DIC) is utilized to enable full-field strain measurements

Micro-Grid Luminescent Solar Concentrators and Related Methods of Manufacturing

Abstract: Luminescent solar concentrators having a grid-based PV design can be implemented in many different ways. In several embodiments, the LSC is implemented using infrared luminophore technology combined with a PV design implementing a grid of PV cells. LSCs can incorporate quantum dots that absorb uniformly across the visible spectrum and photoluminesce down-shifted energy light in the infrared wavelength regime. Some embodiments include PV cells utilizing micro-grid structures that can be implemented for scalable and controllably transparent applications, such as but not limited to power windows targeted for building integrated photovoltaic applications. In a number of embodiments, the LSCs can utilize a unique PV cell form factor and spectral filter coatings to increase the thermal insulation of the window and enhance photocurrent capture by a silicon micro-grid.

Luminescent Solar Concentrator Tandem-on-Silicon with above 700mV Passivated Contact Silicon Bottom Cell

Abstract: Luminescent solar concentrator (LSC) tandem-on-silicon (Si) provides a route towards achieving higher than 30% overall efficiency which can overcome the theoretical efficiency limit of a single junction Si cell. Here, we present optical coupling and performance of high V oc passivated contact Si bottom cell for LSC tandem-on-Si where the top module consists of highly efficient luminophores and an array of micro InGaP cells embedded in a poly (lauryl methacrylate) waveguide. In this device configuration, InGaP cell area coverage is only ~0.5% of the total LSC area which significantly reduces the high cost III-V material usage. The performance of Si sub-cell is investigated under LSC spectrum and is compared against the measurement done under 1 μm thick InGaP filter which mimics the spectrum seen by Si bottom cell in a conventional III-V/Si tandem. V oc of greater than 700 mV has been observed for the passivated contact Si bottom cell in these tandem applications.