Materials Chemistry Frontiers最新文献

Various anti-counterfeiting techniques have wide applications in logistics, aviation, documentation and military. Achieving facile, quick, low-cost, and difficult-to-replicate advanced luminescence anti-counterfeiting plays a crucial role in preventing and deterring the acts of counterfeiting. Halide perovskites (HPs) possess excellent optoelectronic characteristics and structural versatilities, offering great potential in multimodal and multicolor anti-counterfeiting. This review emphasizes the effects of dimensionality, the coordination number, and bond length in HPs on the regulation mechanism of photoluminescence. Through ion doping and external stimuli of HPs, their optical characteristics and crystalline structures can be changed. Furthermore, HPs have attractive application potential due to their sensitivity to controllable light, thermo, solvent, mechano, and other conditions. The unique structure makes HPs exhibit an afterglow phenomenon, providing promising technical support for anti-counterfeiting work and high-level encryption/decryption. Finally, we present future prospects on the development of HPs which include production processes and potential high-end anti-counterfeiting strategies.

Photocatalytic hydrogen production, which directly converts solar energy into green chemical fuel, has received widespread attention. However, despite significant efforts, the efficiency of conventional photocatalytic materials remains below industrial requirements, owing to the intrinsic limitations such as insufficient light absorption and poor carrier transport capability. Metal halide perovskite (MHP) materials feature superior optoelectronic properties and structural flexibility, rendering them highly attractive candidates for photocatalysis. This review provides a concise introduction to the structural characteristics of MHPs and summarizes their recent progress in the field of photocatalytic hydrogen evolution, including single-component MHPs and MHP-based composites. The review also discuss the current challenges and prospects of MHP photocatalysts, which hold promise for advancing photocatalytic solar-to-hydrogen technology.

Although lithium-ion batteries (LIBs) show excellent performance, they have some disadvantages such as poor safety performance and low energy density. Solid-state batteries (SSBs) are widely employed because of their intrinsically high safety, and are considered one of the most promising technologies for next-generation energy storage. However, the relatively high working temperature of solid-state electrolytes (SSEs) makes it difficult to work normally at room or low temperatures. Here, we sum up the common strategies to address this issue. This paper mainly focuses on strategies regarding polymer solid electrolytes, which are more difficult to realize at low temperatures. The optimization of electrolyte design, interface, and battery structure, as well as the underlying mechanism is summarized. Finally, the challenges faced by SSEs and promising strategies at room temperature and low temperature are proposed, providing a vision for the development of SSBs to meet low-temperature applications.

Point defects play a significant role in determining the crystallinity, optoelectronic properties, and carrier lifetime of photovoltaic materials. The open-circuit voltage (V_oc) deficit associated with defects is one of the main factors limiting the power conversion efficiency (PCE) of solar cells. In particular, easily formed deep level defects within the bandgap act as electron–hole non-radiative recombination centers, resulting in Shockley–Read–Hall (SRH) recombination and leading to a large V_oc loss. Generally, the formation of point defects in a semiconductor largely relies on its chemical structure. Compared with conventional 2D and 3D semiconductors, the complicated defects located in non-equivalent atomic sites with a low formation energy in asymmetric 1D structures give rise to a large V_oc deficit, which is a great challenge towards further improving the solar cell efficiency. In this review, we introduce the dependence of defect properties on the dimensions among the binary compound semiconductors. Finally, effective strategies to improve the P-type conductivity of the material, as well as the mixing of 1D materials with other 2D or 3D materials to construct hybrid-dimensional semiconductor compounds, are proposed to enable defect control. From this, we provide guidance for breaking the bottlenecks of thin film solar cells.

The separation of gaseous hydrocarbons is involved in many important industrial processes for manufacturing chemicals, polymers, plastics, and fuels, and is performed through cryogenic distillation, which is heavily energy-intensive. Adsorption-based gas separation technology by using adsorbent materials can potentially fulfill a much energy-efficient gas separation. As a new generation of adsorbent materials, metal–organic frameworks (MOFs) have been demonstrated to have great potential in addressing important gas separations of hydrocarbons. In this review, we outline the uniqueness of MOF adsorbents for their separation application for gaseous hydrocarbons. A variety of microporous MOFs have been developed for separating gaseous hydrocarbons, which have been achieved by fine-tuning their pore sizes for high molecular sieving effects and/or immobilizing binding sites on their pore surfaces for their specific recognition of small molecules. Herein, we highlight recent important progress in this very important topic, focusing on the purification of ethylene, propylene, and butadiene.

Organic field-effect transistors (OFETs) not only act as the ideal platforms for the investigation of charge transport properties of organic semiconductor materials, but also represent the basic units of integrated circuits in flexible and wearable electronic devices. Because of a better understanding of the structure–property relationship of organic semiconductor materials, considerable advancement has been achieved in this field over the past few decades. Among them, metal–organic coordination materials, mainly including discrete metal complexes, coordination polymers and frameworks, have been employed to obtain high-performance OFETs due to their distinct features, such as wide structural diversities, finely tuned HOMO and LUMO energies achieved using different metals and ligands, and metal/ligand-involved pathways for the modulation of charge transport. Herein, the recent development of OFETs based on metal–organic coordination materials and related applications are reviewed. Representative high-performance semiconducting metal–organic coordination materials are systematically summarized into four categories: metal porphyrins and metal phthalocyanines, metal dithiolene/diamine and polypyridine metal complexes, coordination polymers, and metal–organic coordination frameworks. The applications of these transistor devices in organic light-emitting transistors, transistor sensors, photodetectors and memory devices are discussed. Some perspectives and potential guidelines are given in Conclusions for future research studies in this field.

A detailed overview of thermally activated delayed fluorescence conjugated polymers reported from 2015 to present is provided, with a focus on their molecular structures, excited-state properties, and organic light-emitting diode performance. In addition, the rules for regulating the excited-state properties of these TADF conjugated polymers are summarized. By carefully designing the molecular structures of conjugated TADF polymers, their excited-state properties and the energy gaps between the lowest singlet excited states and the lowest triplet excited state can effectively be adjusted. Furthermore, the reverse intersystem crossing rate of conjugated polymers can be increased by enhancing the spin–orbit coupling effect between the triplet and singlet states, and thus optimizing the collection of triplet excitons and improving the device performance, including external quantum efficiency and efficiency roll-off.

The discovery of the aggregation-induced emission (AIE) phenomenon in many classes of organic molecules has revolutionized our understanding of the photoluminescence properties of materials. These breakthroughs have opened up new possibilities for real-life applications and state-of-the-art technologies. AIE luminogens (AIEgens) have emerged as highly useful tools, effectively overcoming the limitations of conventional aggregation-caused quenching (ACQ) luminogens. They find applications in various fields such as biomedical uses, optoelectronics, stimuli-responsive materials, and chemosensing. In particular, the development of highly sensitive and selective AIE fluorescent probes has significantly complemented conventional instrumental analysis methods, offering low-cost, convenient, and rapid detection of target analytes. With intensive research efforts in this area, a wide range of small molecule analytes, including biologically important molecules, drug molecules, volatile organic compounds, and explosives, can now be detected. This review aims to provide an overview of the progress made in the development of AIE-based organic small molecule probes over the past five years.

With the growing interest in metal–organic frameworks (MOFs) and their potential applications, it has become crucial to discover novel MOFs and modify their constituent components. One promising strategy for enhancing the properties of MOFs is the alignment of crystals in specific orientations, which induce anisotropic properties in particular facets. The integration of oriented MOFs at the macroscopic level can be achieved through two main approaches: the direct growth in an oriented manner and the alignment of pre-formed crystals. Direct growth methods involve the adsorption of precursor molecules on substrates, initiating the guided growth based on factors like lattice parameters, surface interactions, and differential growth rates of crystal facets. Integrating MOFs with other substrates in an oriented manner generates novel architectures with unique properties. Another approach is to create alignment using pre-formed MOF crystals, which mainly involves external forces, interfaces of synthetic media, and their assembly. This strategy offers greater flexibility in material selection because of the wide range of pre-existing MOF structures of different compositions. Furthermore, it enables the fabrication of highly ordered alignment over large areas. Ideally, perfectly aligned MOF crystals can mutually synchronize with each other to act like a large single-crystal, ultimately facilitating the full utilization of the directional anisotropic properties over a large area. This review focuses on the preparation strategies and examples of macroscopically oriented MOFs.