Identification of Point Defects in Multielement Compounds and Alloys with Positron Annihilation Spectroscopy: Challenges and Opportunities

Abstract

Three topical materials systems are discussed from the point of view of point defect characterization with positron annihilation spectroscopy. The family of III‐nitride semiconductors and device structures made thereof poses interesting challenges for data interpretation due to preferential localization and annihilation with various elements. Semiconducting oxides with relatively complex crystal lattice structures further highlight the need for combining systematically designed experiments with state‐of‐the‐art theoretical calculations. High‐entropy alloys generate another challenge due to the large number of randomly distributed elements, combining chemical disorder with structural order.

Investigating the role of oxygen vacancies in metal oxide for enhanced electrochemical reduction of NO3− to NH3: mechanistic insights

“…Given that those vacancies (OVs) are also considered types of cavity within crystals, there is an interest in utilizing PAS to detect these OVs. 118,119 Recent work has used PAS to examine VO in TiO 2 samples synthesized at 350 °C and 550 °C (denoted m-350 and m-550, respectively). 119 found in the samples.…”

Positron Annihilation Spectroscopy as a Diagnostic Tool for Probing the First‐Cycle Defect Evolution in Magnesium–Sulfur Battery Electrodes

“…The lifetime of o-Ps picks off annihilation in polymers typically falls between 1 and 10 ns, depending on the size of the free volume holes, and its intensity is related to the fraction of free volume holes. [17,18] In this context, Li Song et al used positron annihilation lifetime spectroscopy as one of the powerful tools to quantify vanadium-defective clusters in the V 2 O 3 lattice to optimize Zn 2þ storage performance. [16] Yang et al used PAL, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) to gain insight into the mechanism of Co doping in Li 2 FeSiO 4 cathode material for lithium-ion battery.…”