Tyndall National Institute

About: Tyndall National Institute is a based out in . It is known for research contribution in the topics: Laser & Semiconductor laser theory. The organization has 1473 authors who have published 3607 publications receiving 71911 citations.

Color‐Coded Batteries – Electro‐Photonic Inverse Opal Materials for Enhanced Electrochemical Energy Storage and Optically Encoded Diagnostics

Abstract: For consumer electronic devices, long-life, stable, and reasonably fast charging Li-ion batteries with good stable capacities are a necessity. For exciting and important advances in the materials that drive innovations in electrochemical energy storage (EES), modular thin-film solar cells, and wearable, flexible technology of the future, real-time analysis and indication of battery performance and health is crucial. Here, developments in color-coded assessment of battery material performance and diagnostics are described, and a vision for using electro-photonic inverse opal materials and all-optical probes to assess, characterize, and monitor the processes non-destructively in real time are outlined. By structuring any cathode or anode material in the form of a photonic crystal or as a 3D macroporous inverse opal, color-coded "chameleon" battery-strip electrodes may provide an amenable way to distinguish the type of process, the voltage, material and chemical phase changes, remaining capacity, cycle health, and state of charge or discharge of either existing or new materials in Li-ion or emerging alternative battery types, simply by monitoring its color change.

Ferroelectricity and large piezoelectric response of AlN/ScN superlattice

Abstract: Based on density functional theory, we investigate the ferroelectric and piezoelectric properties of the AlN/ScN superlattice, consisting of ScN and AlN buckled monolayers alternating along the cry...

Polarization fields in nitride-based quantum dots grown on nonpolar substrates

Abstract: We use a surface-integral method to determine the polarization potential in nitride-based quantum dots (QDs) grown on a nonpolar substrate. There is uncertainty in the literature regarding the sign of the piezoelectric constant ${e}_{15}$. We find that only a negative ${e}_{15}$ can give the reduced electrostatic built-in field found experimentally in nonpolar GaN/AlN QDs. Our analysis of nonpolar InN/GaN QDs indicates that a significant built-in field remains in these structures. We calculate that despite the reduced polarization potential, ground-state electrons and holes can remain spatially separated in GaN/AlN QDs.

Monitoring of cell growth in vitro using biochips packaged with indium tin oxide sensors

Abstract: Cell-based biosensors, which treat living cells as sensing elements, are able to detect the functional information of biologically active analytes and also provide quantitative analysis. In general, they maintain living cells and observe the cellular physiological response after subjecting cells to stimulus and verify the presence and the concentration of these stimuli. This paper describes the use of indium tin oxide (ITO) as a bioimpedance sensor. ITO was chosen as the sensor material due to its optical transparency, electrical characteristics and biocompatibility. These features enabled cells to be visualised and cell signalling to be assessed thus enabling real time non-invasive in vitro analysis of the physiological state of biological cells. The developed biochip integrates optical and electronic devices for monitoring cell behaviour and would facilitate long-term measurement of cytotoxicity. It is envisaged that the developed technology together with proprietary assays will address markets including the pharmaceutical industry, environmental monitoring, health care and security/defence sectors.

Ge1-xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration.

Abstract: In this work we study the nature of the band gap in GeSn alloys for use in silicon-based lasers. Special attention is paid to Sn-induced band mixing effects. We demonstrate from both experiment and ab-initio theory that the (direct) Γ-character of the GeSn band gap changes continuously with alloy composition and has significant Γ-character even at low (6%) Sn concentrations. The evolution of the Γ-character is due to Sn-induced conduction band mixing effects, in contrast to the sharp indirect-to-direct band gap transition obtained in conventional alloys such as Al1-xGaxAs. Understanding the band mixing effects is critical not only from a fundamental and basic properties viewpoint but also for designing photonic devices with enhanced capabilities utilizing GeSn and related material systems.