Structural and Electromagnetic Study of Heavily Doped ZR-Added REBCO Coated Conductors Fabricated by Reel-To-Reel MOCVD

High Temperature Superconducting (HTS) Coated Conductors (CCs) based on epitaxial REBa2Cu3O7-δ (REBCO, RE = rare earth) films with superior mechanical strength and high current carrying capacity are being developed for various large-scale electric power and magnetic applications. The critical current density (Jc) of REBCO coated conductors in a magnetic field is higher than that of any other HTS. However, further Jc enhancement in REBCO coated conductors, particularly in fields perpendicular to the tape (B||c) is necessary due to the highly anisotropic nature of REBCO films. The inherently high in-field angular anisotropy of Jc of REBCO CCs can be diminished by introducing Artificial Pinning Centers (APCs) with optimal size, geometry, and density. The incorporation of a high BaMO3 (BMO; M=Zr, Hf, Sn) dopant concentration in REBCO films to achieve a higher density of nanoscale defects has been demonstrated in this work as a very effective strategy to pin the vortices, especially in moderate-to-high applied magnetic fields and low temperatures. Determination of the optimum chemical composition and the REBCO c-axis lattice parameter has been an important objective to create self-assembled growth of elongated perovskite oxide nanostructures at different Zr dopant levels. Maintaining an optimal texture of the epitaxial REBCO film amidst a high density of BMO nanocolumnar defects was another objective. In the present work, REBCO films with 15 and 25 mol.% Zr addition were grown on biaxially-textured templates on metal substrates using a reel-to-reel Metal Organic Chemical Vapor Deposition (MOCVD) method to systematically investigate the self-assembled BZO generated nanorods and the influence of increased Zr content on the texture and superconducting properties. The optimal composition range of 15 and 25 mol.% Zr-added REBCO to achieve the highest self-field and in-field performance has been determined. Also, the influence of REBCO c-axis lattice parameter on the elastic mismatch strain as well as the internal strain in the REBCO matrix surrounded by BZO nanocolumns was investigated. At the same time, the effects of REBCO c-axis lattice parameter on the self-field Jc at 77 K and the in-field Jc at 30 K in applied magnetic fields of 3 and 9 T (B||c) were found. The demonstrated five-fold improvement in REBCO coated conductor performance at 30 K in magnetic fields of 2-3 T accomplished through a systematic study of the influence of heavy doping of Zr in this work can enable future applications of superconducting devices in several rotating machinery applications such as wind turbines and electric motors.Mechanical Engineering, Department o

Texture and nanostructural engineering of conjugated conducting and semiconducting polymers

© 2020 The Author(s) Conducting polymers have attracted tremendous attention because of their unique characteristics, such as metal-like conductivity, ionic conductivity, optical transparency, and mechanical flexibility. Texture and nanostructural engineering of conjugated conducting polymers provide an outstanding pathway to facilitate their adoption in a variety of technological applications, including energy storage and harvesting devices, flexible optoelectronic devices, and wearable electronic devices. Generally, obtaining high carrier mobility in the presence of high carrier density is challenging and requires precise control of the texture and nanostructure of conducting polymers to avoid the charge localization. Preferential semicrystalline orientation, π–π stacking distances, crystallite size, intra- and interchain couplings, intra- and intercrystallite connections, and grain boundaries are the key parameters that influence the charge carrier mobility and needs to be controlled by the synthesis parameters. This article provides a comprehensive overview of the recent texture and nanostructural engineering development of conducting polymers. In addition, this work describes the fundamental of charge carrier transport mechanisms in conducting polymers; and the latest progress on the optoelectronic characteristics of flexible transparent conductive electrodes based on conducting polymers is reported

Recent Progress in Conjugated Conducting and Semiconducting Polymers for Energy Devices

Advanced conductors (such as conducting and semiconducting polymers) are vital building blocks for modern technologies and biocompatible devices as faster computing and smaller device sizes are demanded. Conjugated conducting and semiconducting polymers (including poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), polythiophene (PTh), and polypyrrole (PPy)) provide the mechanical flexibility required for the next generation of energy and electronic devices. Electrical conductivity, ionic conductivity, and optoelectronic characteristics of advanced conductors are governed by their texture and constituent nanostructures. Thus, precise textural and nanostructural engineering of advanced conjugated conducting and semiconducting polymers provide an outstanding pathway to facilitate their adoption in various technological applications, including but not limited to energy storage and harvesting devices, flexible optoelectronics, bio-functional materials, and wearable electronics. This review article focuses on the basic interconnection among the nanostructure and the characteristics of conjugated conducting and semiconducting polymers. In addition, the application of conjugated conducting and semiconducting polymers in flexible energy devices and the resulting state-of-the-art device performance will be covered

Humidity‐Initiated Gas Sensors for Volatile Organic Compounds Sensing

A new volatile organic compounds (VOCs) sensing concept called humidity-initiated gas (HIG) sensors is described and demonstrated. HIG sensors employ the impedance of water assembled at sensor interfaces when exposed to humidity to sense VOCs at low concentrations. Here, two HIG sensor variants are studied—Type I and Type II. Type I sensors benefit from simplicity, but are less attractive in terms of key performance metrics, including response time and detection limits. Type II sensors are more complex, but are more attractive in terms of key performance metrics. Notably, it is observed that the best-in-class Type II HIG sensors achieve <2 min response times and <10 ppb detection limit for geranyl acetone, a VOC linked to the asymptomatic form of Huanglongbing (HLB) citrus disease. Both Type I and Type II sensors are assembled from off-the-shelf materials and demonstrate remarkable stability at high humidity. HIG sensors are proposed as an attractive alternative to existing VOCs sensors for remote field detection tasks, including VOCs detection to diagnose HLB citrus disease

Humidity‐Initiated Gas Sensors for Volatile Organic Compounds Sensing

A new volatile organic compounds (VOCs) sensing concept called humidity-initiated gas (HIG) sensors is described and demonstrated. HIG sensors employ the impedance of water assembled at sensor interfaces when exposed to humidity to sense VOCs at low concentrations. Here, two HIG sensor variants are studied—Type I and Type II. Type I sensors benefit from simplicity, but are less attractive in terms of key performance metrics, including response time and detection limits. Type II sensors are more complex, but are more attractive in terms of key performance metrics. Notably, it is observed that the best-in-class Type II HIG sensors achieve <2 min response times and <10 ppb detection limit for geranyl acetone, a VOC linked to the asymptomatic form of Huanglongbing (HLB) citrus disease. Both Type I and Type II sensors are assembled from off-the-shelf materials and demonstrate remarkable stability at high humidity. HIG sensors are proposed as an attractive alternative to existing VOCs sensors for remote field detection tasks, including VOCs detection to diagnose HLB citrus disease

oCVD PEDOT-Cl Thin Film Fabricated by SbCl₅ Oxidant as the Hole Transport Layer to Enhance the Perovskite Solar Cell Device Stability

Perovskite solar cells (PSCs) exhibit remarkable power conversion efficiency (PCE) but face limitations due to poor stability, restricting their practical applications. The commonly used hole transport layer, poly(3,4-ethylene dioxythiophene):polystyrene­sulfonate (PEDOT:PSS), suffers from inherent acidity that compromises PSCs device stability through detrimental interactions with the counter electrode and perovskite layer. This study explores the use of oxidative chemical vapor deposition (oCVD) with antimony pentachloride (SbCl5) as a liquid oxidant to fabricate stable, ultrathin, and highly conformal PEDOT thin films, presenting a promising alternative for the hole transport layer in PSCs. The oCVD PEDOT-Cl thin films, grown using liquid SbCl5 oxidant, demonstrate excellent optoelectronic properties, precise control over nanostructure, stability, and integration capabilities, making them a robust and efficient choice as a hole transport layer. Integration of oCVD PEDOT-Cl thin films as the hole transport layer in PSCs yields a remarkable PCE of 20.74%, surpassing the PCE of 16.53% obtained by spin-coated PEDOT:PSS thin films treated with the dimethyl sulfoxide (DMSO) polar solvent. Furthermore, PSCs incorporating oCVD PEDOT-Cl thin films demonstrate a notable 2.5× enhancement in stability compared to PEDOT:PSS-DMSO counterparts. Utilizing as-deposited oCVD PEDOT-Cl thin films fabricated using SbCl5 oxidant with highly conformal characteristics introduces opportunities for enhancing light absorption by the photoactive layer through artificially textured surfaces. This advancement opens up possibilities for the development of PSCs with high performance and enhanced stability