Reviews & Analysis

An emerging annelated thiophene of benzodithiophenedione (BDD) has exhibited its distinguished photovoltaic performance since its planar molecular structure, low-lying highest occupied molecular orbit (HOMO) level and well self-assembly property. In recent 7 years, BDD-based polymer donor have shown a rapid and incredible advancement by utilizing different acceptor materials. Considering the potentials of BDD-based materials, we summarize the most recent advances in the BDD-based photovoltaic materials and highlight the relations between BDD-based molecular structures and photovoltaic properties.

Metal halide perovskites are extraordinary defect-tolerant semiconductors. A unique structural aspect of perovskites is the octahedral coordination for (B-site) metal ions, unlike other semiconductors that exhibit tetrahedral coordination. This octahedral coordination helped to achieve lanthanide doping in halide perovskite nanocrystals in 2017. Fundamental understanding of material design, luminescence and quantum cutting phenomena in lanthanides (with focus on Yb³⁺) doped in CsPbX₃ (X = Cl, Br, I) and Cs₂AgInCl₆ nanocrystals are reported. Subsequently, these doped systems are applied for solar energy harvesting and lighting in both visible and near infrared region. This perspective article summarizes everything important that has happened so far in field and discusses about the future research directions.

Over the last decade, triboelectric nanogenerator (TENG) has been verified to be an effective way of converting daily mechanical energy into electric power or detecting various stimuli in the external environment. To promote the material researches in TENG, we introduce recent progresses in materials and material designs to improve the power generation and sensing performance. Also, we discuss on the future challenges and suggest possible approaches to solve the challenges.

Zn battery family with a long research history in the human electrochemical power supply has been revived and reevaluated in recent years. However, Zn anode in rechargeable batteries still lacks mature and reliable solutions to support the satisfactory cyclability required for the current versatile applications. In this paper, novel functional electrolytes, modified electrode-electrolyte interfaces and advanced electrode structures for addressing the bottlenecks encountered in rechargeable Zn anodes are reviewed, highlighting the mechanisms and open questions in practical applications.

Since the first report in 1970s, W–Cu composites have attracted extensive attentions owing to their outstanding integrated properties of high hardness, wear resistance and electrical conductivity and low thermal expansion coefficient. This article reviewed recent important progress in the fields of preparation, microstructural characterization, and mechanical and physical properties of W–Cu composites. Particularly, new technologies for microstructure refinement and strategies to enhance the comprehensive performance were summarized and evaluated. The future promising research issues, which may break though the bottleneck of existing performance level of W–Cu composites and facilitate the development of other refractory/non-ferrous metals based nanocomposites, were proposed.

The inability to administer oxygen in a controlled and sustained manner into thick artificial tissues has attracted a growing interest towards the design and development of new functional biomaterials. Without a sufficient oxygen supply, tissues suffer from the effects of apoptosis and necrosis. Incorporation of oxygen-releasing materials into scaffolds can help address this challenge. This paper provides an overview of the recent developments and technological advances in engineering oxygen-releasing biomaterials to improve the viability and function of cells and prevent hypoxic tissue death. Recent advances in different types of oxygen-releasing materials, mechanisms of oxygen generation, and their applications are discussed.

Stimulus-responsive hydrogels, with biocompatibility, sufficient water content, similarity to extracellular matrices, and responses to specific environmental stimuli, have recently received massive research interest for fabricating bioactuators. The potential of employing these hydrogels that respond to various stimuli (e.g., pH, temperature, light, electricity, and magnetic fields) for actuation purposes has been uncovered by their performances in biosensing, drug delivery, artificial muscle reconstruction, and cell microenvironment engineering. In this review, a material selection of stimulus-responsive hydrogels and a detailed discussion of recent advances in emerging biomedical applications of hydrogel-based bioactuators are proposed. Existing challenges and future prospects are noted as well.

Overview of up-conversion based condensed phase laser cooling of semiconductor nanostructures. Two critical parameters dictate the likelihood of realizing solid state optical refrigeration: nanostructure emission quantum yield and up-conversion efficiency. This review summarizes both parameters for existing high emission quantum yield semiconductor nanostructures such as CdSe and CsPbBr₃. CsPbBr₃ nanocrystals, in particular, possess optimal parameters for cooling, namely near unity emission quantum yields and up-conversion efficiencies up to 75%. This makes them promising materials for verifiable demonstrations of condensed phase laser cooling.

Mass spectrometry, coupled with soft ionization methods, in conjunction with associated techniques such as tandem mass spectrometry, ion mobility and spectroscopies of sorts, has become a powerful tool for the characterization of advanced materials.

Given the current needs for lasers on flexible substrates or as disposable, low-cost appliances, solution-processable lasers based on tunable colloidal quantum dots (QD) could revolutionize the field of laser-based opto-electronics, much as these QD materials currently do for the growing markets of displays and lighting. In this perspective, we present the status of this rapidly advancing field, followed by a discussion of the remaining challenges and possible avenues for future research and valorization.

Spin transport is the key process for the operation of spinbased devices. Here the recent progress of spin transport in antiferromagnetic insulators (AFMI) is briefed. The observations of the temperature dependence of spin transmission, spin current switching in AFMI and the negative spin Hall magnetoresistance are discussed. The challenges for developing the functionality of antiferromagnetic insulator as well as the unresolved problems from the experimental observations are also discussed.

This perspective highlights various representative manufacturing methods of 3D microelectronic devices and their specific features/limitations. It offers an outlook on future developments in the manufacturing of 3D multifunctional microelectronics devices, and provides some perspectives on the remaining challenges as well as possible solutions. Mechanically guided 3D assembly based on compressive buckling is proposed as a versatile platform that can be merged with micromanufacturing technologies and/or other assembly methods to provide access to microelectronic devices with more types of integrated functions and highly increased densities of functional components.

With two-thirds of the primary energy produced every year rejected as heat, the need for techniques that harvest low-grade waste heat with higher fractions of Carnot efficiency is clear. This article develops a perspective on pyroelectric energy conversion (PEC), that leverages the intrinsic coupling between electrical polarization and temperature in pyroelectric materials where a change in temperature begets a flow of electrical charge. This article will shed light on what thermo-electrical properties are crucial for PEC and the routes to enhance them. Subsequent discussion will cover thermodynamic cycles and device design rules to extract maximum work and power.

Surface-grafting polymer brush (SPB) technique can be used to change the inherent physical/chemical properties of materials surface. Practical applications are paid more attention since SPB technique enables to decorate materials with diverse functions. This paper reviews the current grafting strategies to generate polymer brush layer on surface of solid materials with diverse geometric structures/sizes, and then systematically summarizes the recent research advances on application of polymer brushes-modified materials. Correspondingly, some key challenges of SPB technique with considering its real application in future are discussed. The aim to draft this paper is to tell the readers how to engineer functional materials by SPB technique.

Progress in soft machines and electronics depends on new classes of soft multifunctional materials that can self-repair and heal when damaged so that they can survive the same real-world conditions that human skin and other soft biological materials are typically subjected too. Here, we provide a perspective on current trends and future opportunities in self-healing soft systems that enhance the durability, mechanical robustness, and longevity of soft-matter machines and electronics.

Chemical cross-linking represents a unique approach for creating hybrid materials with enriched properties. This method facilitates the formation of interconnected networks within the material, which can modulate its porosity, conductivity and photophysical properties. Porous morphologies are beneficial for electrochemical applications as they enable the smooth diffusion and penetration of ions, effective ion transport at material interfaces, and also offer a synergy of the properties of the constituent materials and cross-linker. This perspective article highlights the recent advances in the area of covalently cross-linked hybrid metal oxides.

The past decade has witnessed substantial advances in the synthesis of various electrode materials with three-dimensional (3D) ordered macroporous or mesoporous structures (the so-called “inverse opals”) for applications in electrochemical energy storage devices. Yuping Wu from Nanjing Tech University anchored recent advancements in 3D ordered porous (3DOP) electrode materials and their unusual electrochemical properties bound by their intrinsic and geometric structures. The team introduces various 3DOP electrode materials and their representative applications as electrode materials. Additionally, the team also provides research opportunities as well as the challenges to facilitate further contributions to this emerging research frontier.

Biological structures such as amino acids, peptides, and proteins are emerging as promising candidates for piezoelectric energy harvesting and sensing. Here we highlight the position of biological materials in the diverse world of piezoelectric structures, and emphasise how a nanoscale insight into these assemblies, particularly in crystalline form, can pave the way for development of a diverse new array of biocompatible sensors for a greener future. By harnessing advances in high performance computing, we can begin to screen the vast library of biomolecules for optimum candidates, with the ultimate goal of re-engineering biological piezoelectricity by first principles design.

Fluorescent diarylethenes are the most attractive molecules for several applications, such as optical memories, optical switches, or probes for the imaging technology. A wide variety of fluorescent diarylethenes combining with organic fluorophores, emissive polymers, or fluorescent inorganic materials have been developed from the molecular level to the nanoscale during the past decade. In this review, the different molecular and nanomaterial designs providing suitable fluorescence photoswitching property are introduced. Furthermore, the recent development of new applications using fluorescent diarylethene-based molecules and nanomaterials are also summarized.