A Review of Properties, Synthesis and Applications on Lanthanum Copper Oxychalcogenides

The study of layered materials has been a significant and fascinating area due to their unique physical and chemical properties. Among various layered materials, lanthanum copper oxychalcogenides (LaCuOX (X=S, Se, Te)) have drawn a lot of attention of researchers. The study of LaCuOX was initially focused on the optoelectronic performance due to its excellent optical and electronic properties. Recently, it was found that the layered LaCuOX material also exhibits good thermoelectric properties, providing an opportunity to achieve high energy conversion efficiency through the thermoelectric effects. In this report, an overview of recent advances in LaCuOX research is provided, including crystal and electronic structure, synthetic methods, physical properties, practical applications as well as some strategies to optimize their transport properties. Theoretical and experimental results on LaCuOX crystals or thin films are both discussed in this report. Finally, the challenges and outlook for LaCuOX are evaluated based on current progress.

Hydrogen supply chain and production technology

Hydrogen is forecasted as an energy solution for the future thanks to its advantages of cleanliness, abundance and high energy conversion efficiency. The paper briefly introduces the hydrogen supply chain, hydrogen production technologies prevailing or expected in the future, as well as challenges that need to be addressed for a successful transition to a hydrogen-based economy.

Silicon-Based Technologies for Flexible Photovoltaic (PV) Devices: From Basic Mechanism to Manufacturing Technologies

Over the past few decades, silicon-based solar cells have been used in the photovoltaic (PV) industry because of the abundance of silicon material and the mature fabrication process. However, as more electrical devices with wearable and portable functions are required, silicon-based PV solar cells have been developed to create solar cells that are flexible, lightweight, and thin. Unlike flexible PV systems (inorganic and organic), the drawbacks of silicon-based solar cells are that they are difficult to fabricate as flexible solar cells. However, new technologies have emerged for flexible solar cells with silicon. In this paper, we describe the basic energy-conversion mechanism from light and introduce various silicon-based manufacturing technologies for flexible solar cells. In addition, for high energy-conversion efficiency, we deal with various technologies (process, structure, and materials).

Deep-Learning-Based Defect Evaluation of Mono-Like Cast Silicon Wafers

Solar cells based on mono-like cast silicon (MLC-Si) have been attracting increasing attention in the photovoltaic (PV) market due to their high energy conversion efficiency and low cost. As in the production of monocrystalline silicon (MC-Si) and polycrystalline silicon (PC-Si) cells, various defects will inevitably occur during the production process of MLC-Si cells. Although computer vision technology has been employed for defect detection in the production processes, it is still difficult to achieve high accuracy in detecting defects in PV cells using traditional machine vision methods due to defect similarity and complex background. To address this challenge, a deep-learning-based quality assessment algorithm of MLC-Si wafers is proposed. Focusing on the dislocation defects, four different deep learning models are used to conduct migration learning and selected different optimizers (ADAM and SGDM) are used to optimize the network models, achieving good results in evaluating and comparing the quality of ML-Si wafers. On this basis, an improved network model MVGG-19 based on the VGG-19 is designed to improve the prediction accuracy further. The experimental results show that the prediction error of the improved network model is reduced by 63% (compared with VGG-19) and the reasoning speed reaches 10.22 FPS, indicating good detection performance.

Accelerated discovery of a large family of quaternary chalcogenides with very low lattice thermal conductivity

The development of efficient thermal energy management devices such as thermoelectrics and barrier coatings often relies on compounds having low lattice thermal conductivity (κl). Here, we present the computational discovery of a large family of 628 thermodynamically stable quaternary chalcogenides, AMM′Q3 (A = alkali/alkaline earth/post-transition metals; M/M′ = transition metals, lanthanides; Q = chalcogens) using high-throughput density functional theory (DFT) calculations. We validate the presence of low κl in these materials by calculating κl of several predicted stable compounds using the Peierls–Boltzmann transport equation. Our analysis reveals that the low κl originates from the presence of either a strong lattice anharmonicity that enhances the phonon-scatterings or rattler cations that lead to multiple scattering channels in their crystal structures. Our thermoelectric calculations indicate that some of the predicted semiconductors may possess high energy conversion efficiency with their figure-of-merits exceeding 1 near 600 K. Our predictions suggest experimental research opportunities in the synthesis and characterization of these stable, low κl compounds.

Discovery of High Performance Thermoelectric Chalcogenides Through First-Principles High-Throughput Screening

Searching for thermoelectric materials with high energy conversion efficiency is important to solve the energy and environment issues of our society. In this work, we studied the thermoelectric-related transport properties...

Vanadium disulfide nanosheets loaded on carbon cloth as electrode for flexible quasi-solid-state asymmetric supercapacitors: Energy storage mechanism and electrochemical performance

Supercapacitor has predominated current discharge capacity and high energy conversion efficiency, which compared with other energy storage devices has little pollution to the environment. However, it generally exhibits lower energy...