Materials Chemistry Frontiers最新文献

Exploring the structural diversity of skeletons is a pivotal strategy for seeking new energetic materials. However, the complicated skeletons often require cumbersome synthesis, which not only increases the cost but also faces unknown risks for handling energetic metastable intermediates. This review aims to collect recent progress in skeleton-editing reactions of pyrimidine through ring-opening and ring-closing processes, as well as subsequent functional group modifications. The skeleton-editing reactions and further derivations enable easy access to a broad scope of high-energy backbones, such as open-chain, monocyclic, bicyclic, and fused skeletons. Most of the energetic compounds showed promising energy properties. In addition, the low-cost raw materials, simple synthesis steps, practical applications, and other considerations provide a critical reference for further developing new energetic materials.

Metastable-phase materials possess unique structures, high Gibbs free energy, abundant active sites, and adjustable physicochemical properties, making them ideal candidates for optimizing electrocatalysis. As metal oxides are stable under harsh reaction conditions, by controlling the morphology, defects and phase structure of the material, the surface electronic structure of metal oxides can be adjusted to a great extent, and their catalytic performance can be optimized. As a novel addition to the 2D material family, metastable-phase noble metal oxides exhibit significant promise for catalytic reactions. Here, the latest research progress and advantages of 2D metastable-phase noble metal oxides are reviewed, and their application in acidic electrocatalytic water splitting is presented. Finally, the challenges associated with 2D metastable-phase noble metal oxides and future perspectives are discussed.

Owing to its advantages of mild reaction conditions and a single reaction system, Stille coupling has become the main method of developing high-performance photovoltaic polymers. However, Stille coupling polycondensation, following a step-growth polymerization mechanism, still presents challenges in controlling the molecular weights of the polymers, leading to significant batch-to-batch variance. Herein, a strategy based on steric effects was applied to reduce molecular weight fluctuations using the large steric groups of organotin compounds to increase the difficulty of forming the transmetalation transition state. Consequently, we conducted competition experiments with small molecules and synthesized three polymers (PDF-1, PDF-2, and PDF-3) using BDF-based organotin compounds with varying steric hindrance. Theoretical calculations proved that the steric hindrance of organotin compounds significantly influenced the transition state in the transmetalation process. Device measurements revealed that the larger steric hindrance of organostannides could produce polymers with concentrated molecular weights, resulting in only a slight change in the PCEs. Although excessive steric hindrance could affect the photovoltaic properties, leading to lower PCEs, appropriate steric control of organostannides could yield polymer donors with high performance and low batch-to-batch variance. Therefore, this work provides guidelines for developing polymers with minimal batch-to-batch variance.

Although the alkene bond as a connecting unit is widely used to construct D–π–A luminescent molecules, room-temperature afterglow (RTA) systems containing this kind of molecule are extremely rare. In this work, a series of multi-component doped RTA materials were prepared using polyvinylpyrrolidone as the host, 2-(4-chlorophenyl)-1-(4-(diphenylamino)phenyl)ethan-1-one as the guest, dicyanomethylene-4H-pyrans with an alkene bond bridge as the third component, and RhB and Cy5 as the fourth component. Two-component materials emit bright cyan room-temperature phosphorescence; three-component materials emit yellow-green, orange, and red afterglows, respectively; and four-component doped materials further exhibit afterglow at 740 nm in the near-infrared region. The RTA emissions of three-component and four-component materials have been shown to be delayed fluorescence, which is caused by the phosphorescence of the second component transitioning from the triplet state to the singlet state and thus the domino-type Förster resonance energy transfer of S₁–S₁ between different luminescent molecules. The results reveal that using dicyanomethylene-4H-pyrans as the third component can lead to full-color afterglow emissions. This work gives a possible development direction for the construction of RTA materials using D–π–A fluorescent molecules.

Titanium dioxide (TiO₂) has garnered substantial interest as a potential anode material for advanced lithium-ion batteries (LIBs) owing to its superior structural stability, rapid pseudocapacitive kinetics, economic viability, and nontoxicity. Nevertheless, its practical application is significantly curtailed by the limitations in specific capacity and inferior intrinsic electronic conductivity. Although carbonaceous materials can enhance electronic conductivity to a certain extent, the deficiency in lithium storage capacity persists as a critical issue requiring amelioration. Herein, we introduce a unique heterostructure composed of TiO₂ nanobelts and FeS₂ nanoparticles, fabricated through a hydrothermal method, followed by cation exchange and a sulfidation process. For the heterostructure, FeS₂ nanoparticles are in situ anchored on the surface of TiO₂ nanobelts, forming an island-like p–n heterostructure (FeS₂@TiO₂). The incorporation of FeS₂ featuring high specific capacity facilitates the emergence of a built-in electric field at the interface between the two compounds, thereby expediting the charge transport during the lithium storage process. As a consequence, the island-like FeS₂@TiO₂ p–n heterostructure delivers a remarkable reversible capacity of 584.9 mA h g⁻¹ at 1.0 A g⁻¹ after 300 cycles, along with superior rate capability (average capacity of 204.8 mA h g⁻¹ at 10.0 A g⁻¹). Even at 5.0 A g⁻¹, the FeS₂@TiO₂ anode maintains a substantial specific capacity of 251.2 mA h g⁻¹ over 3000 cycles, revealing its outstanding cycling stability. This study suggests that the design strategy coupling TiO₂ with other materials that possess high specific capacity could be broadly applied to enhance its electrochemical performance.

Luminescent solar concentrators (LSCs) have garnered considerable attention for their potential to enhance solar energy harvesting in photovoltaic (PV) systems. However, self-absorption often hinders their efficiency, caused by the overlap between the absorption and emission spectra. Herein, we design, synthesize, and study a series of novel excited-state intramolecular proton transfer (ESIPT) dyes as a new class of self-absorption-free luminophores for efficient transparent LSC-PV devices. HBTM, HBTPM, and HBTBP dyes comprise 2-(benzo[d]thiazol-2-yl)phenol as an electron-donating ESIPT unit functionalized with different π–acceptor moieties of ((3-hexylthiophen-2-yl)methylene)malononitrile, (4-(3-hexylthiophen-2-yl)benzylidene)malononitrile, and (4-(3-hexylthiophen-2-yl)phenyl)(phenyl)methanone, respectively. Theoretical and photophysical analyses confirm the ESIPT nature of these dyes. They show absorption in the UV-blue region and orange-red emissions with large Stokes shifts (4388–10269 cm⁻¹) and decent fluorescence quantum yields (28–47%). Their LSC samples are well prepared by dispersion in a transparent polymethyl methacrylate (PMMA) matrix. The LSC slabs possess good photophysical properties of the dyes with minimal overlap integrals (OI*) of 0.28–1.56% and edge emission efficiencies (η_edge) of 47–57%. Photovoltaic performance assessments reveal power conversion efficiencies (PCE) of 0.46% to 0.68% with external photon efficiencies (η_ext) of 7.69% for HBTM, 6.91% for HBTPM, and 2.98% for HBTBP. Particularly, HBTBP-based LSC exhibits excellent transparency (AVT = 93%; CRI = 97) suitable for window applications. This work represents a significant step toward reducing self-absorption in LSCs while improving photovoltaic performance, paving the way for scalable solar concentrator technologies based on organic materials.

A novel method for identifying counterfeit goods based on the difference between photobleaching rates of spectroscopic marker components is proposed. Controlled photobleaching of the dye is achieved via introduction of halogens (I, Cl, Br, and F) into the aromatic moiety of the dibenzoylmethane (DBM) ligand in coordination compounds of Eu³⁺. A spectroscopic marker model that consists of two coordination compounds with different halogens is developed. These compounds exhibit indistinguishable luminescence spectra and emission intensities at low irradiation power. However, exceeding the threshold irradiation power results in rapid photobleaching of the marker fragment derived from the complex with the highest charge number of halogen atoms. This approach introduces new possibilities for quality control of goods that require storage in light-protected environments. The results obtained during the research have both practical and fundamental significance. For the first time, it is established that the halogenation of the DBM ligand leads to the intersystem crossing process termination. Energy of electronic excitation transfers from the singlet excited state to the ion through a charge transfer state instead of the triplet excited state. Such energy transfer pathways sensitize luminescence of Eu³⁺ more effectively, resulting in an increase in quantum yield up to 64% upon the introduction of chlorine atoms.

Although poly[bis(4-phenyl) (2,4,6-trimethylphenyl)amine] (PTAA) has been extensively investigated as a hole transport material, its performance regarding stability and efficiency still encounters challenges. In this study, through the introduction of a novel guest molecule BQ-BO, the energy level configuration, hole transport, and interface passivation of PTAA have been significantly enhanced. The large conjugated electron-deficient core and methoxy-substituted triphenylamine arm structure of BQ-BO not only optimize the HOMO energy level but also enhance the hole mobility and conductivity, attaining a photoelectric conversion efficiency of 21.81%. It also exhibited outstanding thermal stability, maintaining an initial efficiency of 90% after 1000 hours of continuous heating at 85 °C, in contrast to a pure PTAA-based device whose efficiency dropped to 70% after 400 hours.

Radioactive strontium-90 (⁹⁰Sr²⁺) in wastewater poses a significant threat to both the environment and living organisms. Conventional treatment strategies, such as ion-exchange resins followed by cement solidification, can still carry the risk of leakage under certain conditions. Low-silica zeolites have demonstrated strong cation sorption capabilities, with CHA zeolites showing particular promise for nuclear wastewater treatment. However, synthesizing low-silica CHA zeolites with Si/Al ratios around 2 typically requires fluorides or complex crystallization processes. In this study, we present a one-step, fluoride-free synthesis method for low-silica CHA zeolites using the silicoaluminophosphate (SAPO) zeolite SAPO-35 as the seed. The SAPO-seeded synthesis method enhances the formation of Al-pairs within the CHA framework by releasing partially connected Si and Al species from the SAPO seed. This significantly improves the zeolite's capability to capture the divalent Sr²⁺. The resulting zeolite exhibits a 10% higher Sr²⁺ sorption capacity per ion-exchange site compared to CHA zeolites synthesized without the SAPO seed. The synthesized zeolite exhibits exceptional Sr²⁺ removal efficiency across dosages of 1/50–1/500 g mL⁻¹ and the pH range of 3–12. At temperatures of 25 °C, 60 °C, and 80 °C, the sorption capacities reach 112 mg g⁻¹, 144 mg g⁻¹, and 186 mg g⁻¹, respectively. This work highlights the potential of SAPO-seeded synthesis as a practical and scalable approach for producing Al-pair-enriched, low-silica CHA zeolites, indicating the high effectiveness for removing ⁹⁰Sr²⁺ from nuclear wastewater and offering a promising solution for radioactive wastewater management.

In recent years, the issue of increasing electromagnetic pollution has posed significant challenges for researchers in the field of electromagnetic dissipation, highlighting the urgent need for effective solutions. Metal–organic frameworks (MOFs) have garnered considerable attention due to their compositional designability, large specific surface area, and tunable chemical structure, making them highly desirable precursors for electromagnetic wave absorption materials (EMWAMs). MOF-based EMWAMs exhibit remarkable performance advantages, such as lightweight properties, high loss capability, and a wide effective absorption bandwidth. These advantages are primarily attributed to their excellent impedance matching and multiple attenuation mechanisms. This paper provides a concise discussion on the relationship between the mechanisms and microstructure of EMWAMs. The research progress of MOF-based EMWAMs in recent years is reviewed, including the classification of MOF and MOF composite precursors, design principles and preparation methods. Finally, the problems, challenges and future opportunities of MOF-based EMWAMs are presented. We aim for this review to offer new insights into the design and fabrication of MOF-based EMWAMs, thereby enhancing both the fundamental understanding and practical application of these materials.