Year: 2019
Type: article
Abstract: In situ fabrication of nanostructures within a solid-polymer electrolyte confined to subwavelength-diameter nanoapertures is a promising approach for producing nanomaterials for nanophotonic and chemical sensing applications. The solid-polymer electrolyte can be patterned by lithographic photopolymerization of poly(ethylene glycol) diacrylate (PEGDA)-based silver cation (Ag+)-containing polyelectrolyte. Here, we present a new method for fabricating nanopore-templated Ag nanoparticle (AgNP) arrays by in situ photopolymerization using a zero-mode waveguide (ZMW) array to simultaneously template embedded AgNPs and control the spatial distribution of the optical field used for photopolymerization. The approach starts with an array of nanopore-confined recessed Ag ring electrodes fabricated by sequential layer-by-layer deposition and focused ion beam milling. These structures have an optically transparent bottom, allowing access of the optical radiation to the attoliter-volume ZMW region to photopolymerize a PEGDA monomer solution containing AgNPs and Ag+. The electric field intensity distribution is calculated for various ZMW optical cladding layer thicknesses using finite-element simulations, closely following the light-blocking efficiency of the optical cladding layer. The fidelity of the polyelectrolyte nanopillar pattern was optimized with respect to experimental conditions, including the presence or absence of Ag+ and AgNPs and the concentrations of PEGDA and Ag+. The self-templated approach for photopatterning high-resolution photolabile polyelectrolyte nanostructures directly within a ZMW array could lead to a new class of metamaterials formed by embedding metal nanoparticles within a dielectric in a well-defined spatial array.
Source: Frontiers in Chemistry
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,490
Awards: G6328961138, IN THIS PROPOSAL THE FUNDAMENTAL QUANTUM AND PHOTONIC INTERACTIONS OF BIMETALLIC ATOMIC-SCALE JUNCTIONS (ASJS) WILL BE EXPLORED WITH THREE MAJOR SPACE TECHNOLOGY-RELATED APPLICATIONS IN FOCUS: 1)CHEMICAL SENSING 2)SMART/METAMATERIALS AND 3)MEMRISTORBASED COMPUTING. AN ASJ IS A TYPE OF QUANTUM-POINT CONTACT CREATED BY ELECTROCHEMICALLY DEPOSITING SILVER BETWEEN TWO NANOSCALE ELECTRODES. THIS CONNECTION CAN BE FORMED AND DESTROYED BY APPLYING THE APPROPRIATE VOLTAGE POTENTIAL ACROSS THE ELECTRODES AND THUS CONTROLLED TO THE POINT WHERE THE JUNCTION NARROWS TO THE WIDTH OF A SINGLE ATOM. AT THIS POINT THE JUNCTION CAN EXHIBIT A PHENOMENON KNOWN AS QUANTIZED CONDUCTANCE. IN THIS REGION THE JUNCTION IS ESPECIALLY SENSITIVE TO DISTURBANCES IN THE SURROUNDING ENVIRONMENT. PREVIOUS RESEARCH HAS DEMONSTRATED THE POTENTIAL OF A SINGLE ASJ IN SENSING CHEMICALS BOUND TO THE JUNCTION AT THIS NARROWEST SECTION; THIS PROPOSAL WILL EXTEND ON THAT WORK BY EXAMINING PARALLEL AND SERIAL ARRAYS OF ASJS FOR CHEMICAL SENSING AND MEMRISTIVE COMPUTING AS WELL AS THE INTERACTION OF THE JUNCTIONS IN 3-DIMENSIONAL CONFIGURATIONS WITH LIGHT FOR METAMATERIALS. THE OBJECTIVES OF THIS PROJECT ARE TO ESTABLISH CONTROL OVER JUNCTION GROWTH IN MASSIVELY PARALLEL ARRAYS BOTH THROUGH DIRECT ELECTRICAL CONTACT AND WITH PHOTO-INDUCED CHARGING THEN UTILIZE THIS CONTROL TO EXAMINE THE POTENTIAL APPLICATION OF THESE JUNCTIONS IN THE AREAS DESCRIBED ABOVE. JUNCTIONS WILL BE CREATED USING ELECTROCHEMICAL DEPOSITION BETWEEN CONDUCTIVE ELECTRODES WHICH MAY BE LITHOGRAPHICALLY-DEFINED MACROSCALE ELECTRODES ON A WAFER A CONDUCTIVE AFM TIP OR NANOPARTICLES STIMULATED WITH FOCUSED LASERS. ACHIEVING THESE OBJECTIVES WOULD BE HIGHLY SIGNIFICANT TO BOTH NASA AND THE COMMUNITY AT LARGE. DUE TO THE JUNCTIONS SMALL SPACE AND WEIGHT A MASSIVELY PARALLEL ARRAY OF JUNCTIONS WOULD NOT TAKE UP MORE THAN A FEW SQUARE MILLIMETERS OF AREA ON A SILICON WAFER YET COULD PERFORM A WIDE ARRAY OF FUNCTIONS; THUS THEY ARE IDEALLY SUITED TO THE TIGHT WEIGHT AND SIZE REQUIREMENTS OF TERRESTRIALLYLAUNCHED SPACE MISSIONS. THE APPLICATIONS OF ASJS IN CHEMICAL SENSING AND MEMRISTOR-BASED NEURAL NETWORK APPLICATIONS COULD ALLOW FOR NEW EXPERIMENTS AND DATA ANALYSIS NOT POSSIBLE WITH EXISTING TECHNOLOGY. IN ADDITION THE FUNDAMENTAL INSIGHTS INTO QUANTUM AND PHOTONIC PHENOMENA GAINED BY DEVICES THAT OPERATE AT ROOM-TEMPERATURE AND UNDER SIMPLE CONDITIONS WOULD ALSO GREATLY BENEFIT THE SCIENTIFIC COMMUNITY AND SCIENCE EDUCATION.
OpenAlex ID: W2940317418