Layered oxychalcogenides: structural chemistry and thermoelectric properties

Layered oxychalcogenides have recently emerged as promising thermoelectric materials. The alternation of ionic oxide and covalent chalcogenide layers found in these materials often results in interesting electronic properties, and also facilitates the tuning of their properties via chemical substitution at both types of layers. This review highlights some common structure types found for layered oxychalcogenides and their interrelationships. This review pays special attention to the potential of these materials for thermoelectric applications, and provides an overview of the thermoelectric properties of materials of current interest, including BiCuSeO

The analysis of thermoluminescent glow peaks of CaF2 : Dy (TLD-200) after beta-irradiation

WOS: 000179131600015Variable dose (VD), T-m-T-stop, initial rise (IR), variable heating rate (VHR), peak shape (PS) and computerized glow curve deconvolution (CGCD) methods are used to determine the number of peaks, the order of kinetics (b), the activation energy (Ea) and attempt-to-escape frequency (s) associated with the glow peaks in CaF2: Dy (TLD-200) after beta-irradiation between the dose level 0.1 and 110 Gy. The T-m-T-stop procedure indicates that the glow curve of this crystal consists of at least nine glow peaks. The dose variation experiment indicates that seven of them, namely peaks 1-6 and 8, are of first-order kinetics and peaks 7 and 9 are of general-order kinetics. However, the T-m-T-stop procedure and the CGCD method have indicated that peak 6 has general-order kinetics too. The activation energy found with the IR, VHR, PS and CGCD methods for peak 4 yield very close values. For all other peaks, there is no agreement between the results of all the applied methods. This work also indicates that the post-irradiation annealing and the heating rate have pronounced effects on the evaluated kinetic parameters of all glow peaks

The analysis of dosimetric thermoluminescent glow peak of alpha-Al2O3 : C after different dose levels by beta-irradiation

WOS: 000184554400019The variable dose (VD), T-m-T-stop, initial rise, variable heating rate, peak shape and computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks, the order of kinetics (b), the activation energy (Ea) and attempt-to-escape frequency (s) associated with the dosimetric glow peak of alpha-Al2O3 : C after beta-irradiation at a dose level between 0.02 and 288 Gy. The E-a-T-stop and CGCD methods indicated that the dosimetric peak of this crystal is the superposition of at least two components (peak 2a and 2b). When the dose level reaches and exceeds saturation point, a third peak (peak 2c) is also evident on the low temperature side of the dosimetric peak. The VD and CGCD methods indicated that both components of the dosimetric peak have general-order kinetics that change with doses. The dose responses of peak 2a follow linear, supralinear, saturation and sublinear patterns, whereas peak 2b does not exhibit supralinear behaviour. They are saturated at different dose levels, peak 2a at D = 10 Gy and peak 2b at D = 5 Gy. E-a-T-stop plots obtained at two different dose levels (D = 10 and 1 Gy) indicated that the efficiency of thermal quenching effect on this sample is highly dependent on the dose level and decreases with increasing dose level, which also has pronounced effects on the evaluated kinetic and thermal quenching parameters of the dosimetric peak