With the development of donor and acceptor materials, the power conversion efficiency(PCE) of organic solar cells(OSCs) has continuously made breakthrough in recent years. Particularly, the emergency of non-fullerene acceptor Y6 has enabled the device efficiency of OSCs over 15%. Y6 has been applied in many aspects and greatly improved its photovoltaic properties. This review focuses on the applications of Y6 in binary, ternary and quaternary, layer-by-layer, flexible, tandem and semitransparent organic solar cells, meanwhile, the future structure optimizations and device applications of Y6 have been outlooked.

Gold nanoclusters are a new kind of "Quasi-molecule" nanomaterials with luminescent properties. By controlling the number of gold atoms and the composition of ligands, gold nanoclusters can realize the emission of different bands under the same excitation, thus showing the "colorful" luminescence characteristics, which make them widely used in many fields such as photocatalysis, optical devices, sensing, and imaging. Therefore, the development and optimization of the synthesis method of gold nanoclusters with good fluorescence performance have been a research hotspot in the field of chemical biomaterials. In this paper, based on the luminescent color of gold nanoclusters, the synthesis principles and methods of corresponding gold nanoclusters are summarized according to different colors, and the factors affecting the luminescent properties of gold nanoclusters are explored. At the same time, the applications of these "colorful" gold nanoclusters in biosensing and bioimaging in recent years are summarized, and the challenges and development trends of gold nanoclusters are discussed and prospected respectively.

Carbon chain(CC) is a new type of carbon allotrope with one-dimensional sp-hybridized structure. Its unique chemical bonds result in superior properties than that of fullerene, graphene, and carbon nanotubes. For example, theoretical calculations predict that the mechanical strength of the CC is several times greater than that of graphene. Also, the thermal conductivity of the CC is similar to that of graphene and carbon nanotubes. In addition, the CC is a semiconductor with direct band gap, which can be tuned via its length, i.e., the longer the CC, the smaller the band gap. Although the research on the CC has bee started as early as the 19th century, making progress was indeed difficult and slow. Recently, several breakthroughs in research on CC has attracted extensive attention to CC again all over the world. In this review, the concept, structure, and properties of the CC are first introduced. On this basis, typical synthesis methods and applications are detailedly presented. Especially, several recent major breakthroughs in the field of the CC are highlighted. Most importantly, perspectives on the research directions of the CC are indicated. We hope that this review is able to attract domestic and international peers’ attention on this new type of one-dimensional sp-hybridized carbon allotrope.

Fluorescent probe analysis, as a rapidly developed analytical method with high sensitivity, good selectivity, and fast responsibility, has been favored in environmental and life science field. And near-infrared fluorescent probe is one of the most developed fluorescent probes. It has been widely employed in detection, tracking and imaging of biomolecules in complex biological systems such as cells and tissues due to its distinguished features including long emission wavelength(600 to 900 nm), low cell damage, strong tissue penetration and low spontaneous fluorescence background. In this review, we summarize the development of near-infrared fluorescent probes in detection and imaging of metal ions(Hg²⁺, Cu²⁺, Zn²⁺, Al³⁺, Fe³⁺), small biological molecules(Cys, N₂H₄, H₂S, H₂O₂), biological macromolecules(Leucine aminopeptidase, β-galactosidase) and other important biological molecules in recent five years. We further give the in-depth discussion on the in vitro and in vivo analytical applications of near-infrared fluorescent probes, and propose their future perspectives.

Photoacoustic(PA) imaging, as a new type of imaging technique that offers strong optical absorption contrast and high ultrasonic resolution, shows great application prospects in the early disease diagnosis for its characteristics of deep tissue penetration and high spatial resolution. However, traditional “always on” PA contrast agents have many disadvantages such as low signal-to-noise ratio, poor selectivity and specificity. In contrast, activatable PA contrast agents, where the imaging signal can be changed in response to pathologic parameters, have shown decreased background signal and improved selectivity and specificity in early disease diagnosis. Moreover, these contrast agents can obtain pathological parameters and information of various diseases at the molecular level by rational design to their structures, providing important guidelines for the optimization of treatment options. Therefore, activatable PA contrast agents hold greater promise in clinical practice than traditional “always on” PA contrast agents. In this review, we describe the recent advances in the development of activatable PA contrast agents. The design mechanisms and proof-of-concept applications of these activatable PA contrast agents are summarized in detail. The use of these activatable probes to detect different pathologic parameters(such as metal ions, enzymes, reactive nitrogen and reactive oxygen species) is highlighted. Finally, current challenges and future perspectives in this emerging field are also analyzed.

In order to detect, analyze, and identify exhaled gas, electronic-nose combined with artificial intelligence has become a hot spot in the field of non-invasive medical detection. However, gas sensing materials cannot meet the requirements of high sensitivity as well as high selectivity at room temperature, which seriously hinders the application of gas sensors in the field of health care. It is still challenging to find suitable materials for the electronic-nose. With many unique properties: a wide variety, large specific surface area, strong electrical conductivity, rich functional groups on the surface, and adjustable bandwidth, novel two-dimensional MXenes material has become a star candidate for the gas sensor of highly sensitive and low energy consumption. In this review, we summarize the latest research achievements of MXenes based materials with the special structure in gas sensing, focus on the gas sensing mechanism and modification methods, and probe into the problems and challenges still existing in the application of MXenes materials in gas sensing.

In order to detect, analyze, and identify exhaled gas, electronic-nose combined with artificial intelligence has become a hot spot in the field of non-invasive medical detection. However, gas sensing materials cannot meet the requirements of high sensitivity as well as high selectivity at room temperature, which seriously hinders the application of gas sensors in the field of health care. It is still challenging to find suitable materials for the electronic-nose. With many unique properties: a wide variety, large specific surface area, strong electrical conductivity, rich functional groups on the surface, and adjustable bandwidth, novel two-dimensional MXenes material has become a star candidate for the gas sensor of highly sensitive and low energy consumption. In this review, we summarize the latest research achievements of MXenes based materials with the special structure in gas sensing, focus on the gas sensing mechanism and modification methods, and probe into the problems and challenges still existing in the application of MXenes materials in gas sensing.

The dicarbonylation of acetylene small molecule, produced based on non-petroleum routes, can produce a large number of high value-added chemicals, which is of great significance in the environmental treatment of CO gas emissions and the chemicals application. The artide mainly reviews the advances in research on the catalyst in acetylene carbonylation from homogeneous to heterogeneous, and summarize the effects of catalyst types and additives on the acetylene mono-/bi-carbonylation reaction activity. Based on the analysis of the reaction mechanism, this article introduces the design ideas for the preparation of high-efficiency catalysts by adjusting the structural sensitivity factors(size effect and morphology effect). Thus the method for controllable preparation of the micro-nano structure of the heterogeneous catalyst and the structure-activity relationship are further reviewed, with a view to provide guidance for the design of a heterogeneous catalytic system for efficient acetylene carbonylation in the future.

Janus particles are promising materials for stabilizing emulsion, self-assembly, biomedicine and functional coatings due to its anisotropic properties in mechanical, magnetic, optical, electrical properties, surface hydrophilicity and hydrophobicity. The amphiphilic Janus particles, in which one face possesses hydrophobicity and the other face possesses hydrophilicity, have received considerable attention in stabilizing Pickering emulsion owing to its property of surfactant and solid particle. In this paper, the fabrication methods of amphiphilic Janus particles are summarized, and their advantages and defects are compared firstly. Then the effects of amphiphilic Janus particles on the stability of Pickering emulsion are highlighted. Finally, the development of amphiphilic Janus particles in the future is prospected.

Iron oxychloride(FeOCl) is a typical iron-based material with layered structure. It was discovered in the 1930s, and since the 1970s, has been extensively studied as a unique host in the field of supramolecular intercalation chemistry. The modification of FeOCl is much more flexible and easier than traditional iron(hydr)oxides due to the layered structure. In 2013, our group reported that FeOCl has excellent Fenton-like activity, which shows the promising potentialities for practical applications. Inspired by the properties of FeOCl and encouraged by our result, FeOCl and its intercalation compounds have recently attracted significant attention in catalysis and energy storage. In this review, the characteristics of pristine FeOCl and its intercalation compounds are summarized, especially intercalation-induced crystal and electronic structure changes. And then we focus on the contributions made by these materials toward advanced oxidation processes(AOPs), selective oxidation, electrode materials and other fields. Finally, challenges and future perspectives are reviewed in terms of structural design and the improvement of stability.

Organic-inorganic hybrid perovskite solar cell(PSC) is a photovoltaic device with great potential for development. In the past decade, many studies have been devoted to the preparation of high-performance PSC, and have made amazing progress. Device efficiency has now exceeded 25%. The electron transport layer plays a vital role in extracting and transporting photogenerated electrons, blocking holes, modifying interfaces, adjusting interface energy levels, and reducing charge recombination. Inorganic n-type materials, such as TiO₂, ZnO, SnO₂ and other metal oxide materials have the advantages of low cost and good stability, which are often used as ETLs in traditional PSC. Organic n-type materials, such as fullerenes and their derivatives, naphthalene diimide polymers and small molecules, have good film-forming properties and strong electron transport capabilities, which are often used as ETLs in inverted PSCs. This review will systematically classify the electron transport materials for perovskite solar cells, outline their preparation methods, introduce their charge transport mechanism and effect in perovskite solar cells. The latest research progress of metal oxide materials, organic molecular materials, composite materials, multilayer electron transport layer materials and their modification methods are systematically discussed. Finally, the practical application and development prospects of the electron transport layer materials towards high-performance PSC are prospected. In summary, this review helps to better understand the preparation and mechanism of various electron transport layer materials related to perovskite solar cells, and provides strategies for further understanding and preparing high-performance PSCs.

Lignin is one of the richest natural biomass, and more importantly, it is the only renewable resource containing aromatic structures in nature reserves. However, a large part of this resource are abandoned by far due to the complex structure, which makes the effective utilization of lignin quite difficult. It is well known that lignin can be transformed into a series of substitutes for petrochemical products via some redox processes. Beyond that, not only the oxygen-rich functional groups in lignin structure, but also the sulfur element introduced during the pulping process can provide effective active sites, making lignin resource a promising substrate of various catalysts. In this paper, following a brief summary of the species and structural characteristics of lignin resource, the applications of lignin-based catalysts in acid-base catalytic reactions, such as hydrolysis of biomass platform compounds, electrocatalysis reactions,oxidation-reduction reactions catalyzed by supported metal nanoparticles are summarized according to the catalytic mechanism and modification methods of lignin. The effects of lignin types, preparation or activation conditions on the performance of lignin-based catalytic materials are also discussed in detail. Besides, the current problems and future develop prospects of the development of lignin-based catalysts are also indicated.

In recent years, the use of abundant and renewable biomass resources to prepare high value-added chemicals and liquid fuels is one of the hot spots in the chemical research field, which is in line with the national strategy of sustainable development. 5-hydroxymethylfurfural(HMF)is one of the key biomass platform compounds, widely used in the preparation of fine platform compounds, drug intermediates, polymer synthesis and liquid fuel precursor. Therefore, the selective oxidation of HMF has gradually become a research hotspot in the field of biomass. This paper mainly introduces the research on preparation of biomass derivatives such as DFF, FFCA and FDCA by selective oxidation of HMF in last five years, and the transformation of biomass with HMF as intermediate. The selective oxidation of HMF mainly focuses on two ways:thermalcatalytic and photocatalytic. Among them, the selective oxidation of HMF to DFF and FDCA by thermalcatalytic is widely studied. The catalytic system in this approach mainly includes the noble metals and non-precious metals, which are introduced herein. In the few photocatalytic pathways, the main catalytic system is g-C₃N₄ catalyst. In addition, the deficiencies in the research on the oxidation of HMF are pointed out and the possible solutions are proposed.