Ang Feng

TU Wien | TU Wien · Institute for Microelectronics

An accurate measurement of radiation doses is required to ensure efficient use of electromagnetic radiation in medical diagnostics, agriculture, or general lighting applications. Yet, existing dosimeters usually face the issues of cumbersome manipulation, time-consuming analysis, or power-supply requirement. Here, an all-round dosimeter is reported...

A good control over the valence state of dopants in luminescent materials or phosphors is important for the development of highly efficient phosphors for white light-emitting diodes (LEDs). Detailed spectroscopic studies allow us to reveal optically induced charge transfer processes and elucidate the underlying mechanisms in phosphors with addition...

Glow‐in‐the‐dark materials have been around for a long time. While formerly materials had to be mixed with radioactive elements to achieve a sufficiently long and bright afterglow, these have now been replaced by much safer alternatives. Notably strontium aluminate, SrAl2O4, doped with europium and dysprosium, has been discovered over two decades a...

Flexible X-ray storage phosphor sheets are regarded as promising alternatives to conventional electronic flat-panel X-ray detectors, enabling X-ray imaging and dosimetry in less accessible situations. However, it is a challenge to develop phosphor-based detectors with high memory stability and convenient readout processes. Here, an approach to real...

The performance of persistent phosphors under given charging and working conditions is determined by the properties of the traps that are responsible for these unique properties. Traps are characterized by the height of their associated barrier for thermal detrapping, and a continuous distribution of trap depths is often found in real materials. Ac...

Inorganic materials combining photochromism and luminescence modulation characteristics have great potential in dual-mode rewritable optical storage due to their unique optical features and excellent thermal stability. However, the failure of achieving a large luminescence modulation and a strong photochromic efficiency in photostimulated inorganic...

The performance of persistent phosphors under given charging and working condition is determined by the properties of the traps that are responsible for these unique properties. Traps are characterized by the depth of their associated thermal barrier and a continuous distribution of trap depths is often found in real materials. Accurately determini...

The relation between the optimum working temperature of persistent ‘glow‐in‐the‐dark’ phosphors and their thermoluminescence glow curve is investigated. In article number 2000060, Jiaren Du, Ang Feng, and Dirk Poelman present new perspectives for designing and screening persistent phosphors for various ambient conditions, and beyond.

Phosphors featuring persistent luminescence, as distinctive photonic materials, have been explored extensively owing to their unusual properties and commercial interest as self‐sustained emitters in night‐vision surveillance, emergency signage, optical data storage, and in vivo bio‐imaging. However, widespread utilization of persistent phosphors at...

The phenomenon of mechanoluminescence (ML), where phosphors emit light when pressure is applied, is considered to be closely related to the crystallographic structure of those phosphors. In this work we unravel this connection for the anorthite solid solution Ca1-xSrxAl2Si2O8, which displays two important phase transitions as a function of strontiu...

Mechanoluminescence (ML) is the phenomenon describing the emission of light during mechanical action on a solid, leading to applications such as pressure sensing, damage detection and visualization of stress distributions. In most cases, this mechanical action releases energy that was previously stored in the crystal lattice of the phosphor by mean...

The demand of smart composite materials is increasing in all sectors. With it, the need of new sensor technologies for structural health monitoring purposes is also increasing. The requirements for the next generation of sensing devices are quite high. Ideally, they should be able to sense different physical parameters, in-situ, on a (sub-)micromet...

The phenomenon of mechanoluminescence (ML), where phosphors emit light when pressure is applied, is considered to be closely related to the crystallographic structure of those phosphors. In this work we unravel this connection for the anorthite solid solution Ca1-xSrxAl2Si2O8, which displays two important phase transitions as a function of strontiu...

The monitoring of stress changes in structural components under various kinds of dynamical loading is crucial for the assessment of their integrity and lifetime. In addition to many methodologies available, such as strain gauges, optical fiber sensors, X-Ray diffraction and digital image correlation, we introduce a novel non-contact method to visua...

Mechanoluminescence (ML) is the non-thermal emission of light as a response to mechanical stimuli on a solid material. While this phenomenon has been observed for a long time when breaking certain materials, it is now being extensively explored, especially since the discovery of non-destructive ML upon elastic deformation. A great number of materia...

CaZnOS:Mn(2+) is a rare-earth-free luminescent compound with an orange broadband emission at 612 nm, featuring pressure sensing capabilities, often explained by defect levels where energy can be stored. Despite recent efforts from experimental and theoretical points of view, the underlying luminescence mechanisms in this phosphor still lack a profo...

BaSi2O2N2: Eu2+ is a mechanoluminescent (ML) phosphor that shows high sensitivity to dynamic loads. Our tensile tests show that the ML intensity is independent of prior stress and its spatial distribution agrees well with the Von Mises strain. However, the magnitude of ML intensity, total ML energy and ML decay time depend on the strain rate and l...

This study fully investigated the vacuum ultraviolet excitation spectra of pure and rare-earth (RE=Eu, Tb and Dy)-doped A2Zr(PO4)2 (A=Li, Na and K) phosphors. The synthesized Na and Li compounds were characterized by XRD showing two new types of phases after indexation. Although these three pure compounds had different crystal structures, they exhi...

The electronic structure of CaZnOS calculated using the CASTEP mode is an intermediate band gap semiconductor with a direct band gap of 2.4 eV. Ce3+-activated CaZnOS samples were prepared by a solid-state reaction method at high temperature and their luminescence properties under UV-visible and X-ray excitation were investigated. CaZnOS:Ce3+ exhibi...

RE3+ (RE = Pr, Sm, Er, Tm)-activated CaZnOS samples were prepared by a solid-state reaction method at high temperature, and their photoluminescence properties were investigated. Doping with RE3+ (RE = Pr, Sm, Er, Tm) into layered-CaZnOS resulted in typical RE3+ (RE = Pr, Sm, Er, Tm) f-f line absorptions and emissions, as well as the charge transfer...