Materials Chemistry Frontiers最新文献

In single-molecule junctions, quantum interference (QI) effects manifest even at room temperature and can be explained by simple quantum circuit rules (QCR), and a rather intuitive magic ratio (MR), theory. These rules characterise how individual moieties contribute to the overall electrical conductance (G), of a molecule and how the overall G can change when the connectivities between different moieties is varied. Here we examine the electrical conductance of a single-ferrocene junction when the two metal electrodes connect to both upper and lower cyclopentadienyl (CP) rings and compare this with the conductance when both electrodes are contacted to only the upper CP ring. In the case of the former, the angle of rotation θ between the upper and lower rings could be changed by varying the distance between the electrodes. The main aim of our investigation is to determine how QI within the ferrocene core is affected by the length of linker groups, which connect the core to electrodes. We find that when θ = 0, short and long molecules exhibit destructive QI (DQI) features within the HOMO–LUMO gap, whereas as θ is increased, the DQI is alleviated. However, DQI within the HOMO–LUMO gap is alleviated at entirely different rotation angles of θ >20° for the molecule with longer linkers, compared to >60° for the shorter molecule. This shows that interference patterns within the ferrocene core are not simply a property of the core alone, but are a holistic property of the molecule as a whole. We investigated the Seebeck coefficients S of these molecules and found that S of the longer molecules can reach 250 μV K⁻¹, which is significantly higher that the Seebeck coefficients of the shorter molecules.

Developing stretchable electromagnetic interference (EMI) shielding materials is highly desirable for integrated flexible electronic devices, because they often suffer from the decrease of EMI shielding effectiveness (SE) under large tensile deformation. Combining elastic polymers and liquid metals (LM) together may provide a promising solution. However, it is still a great challenge to understand how to avoid the leakage of LM under tensile deformation. Herein, layer-by-layer thermoplastic polyurethane/liquid metal (TPU–LM) composite films with a nanofiber–LM interlocked structure are prepared. The porous TPU nanofibers provide a supporting skeleton with high mechanical properties to encapsulate the LM to avoid its leakage, and the LM layers can therefore maintain a continuous conductive network when it is stretched significantly. As a result, the TPU–LM composite film not only exhibits high EMI SE and anti-leakage performance under large tensile deformation, but also presents excellent chemical resistance, high/low-temperature resistance (−196 to 100 °C), self-cleaning and temperature-visualizing performances, indicating potential applications in flexible wearable electronic devices with large deformation. In short, the composite films with a nanofiber–LM interlocked structure not only provide a promising solution to avoid the leakage of LM in practical applications, but can also be used in self-cleaning and temperature-visualizing multifunctional applications.

Deuteration of Pt(II) complexes not only enhances their chemical stability but also broadly influences their phosphorescence. Herein, we examine these isotope effects, which exhibit site-dependent variations. Deuterated complexes display noticeable deceleration in spin-converted intersystem crossing and phosphorescent transitions, revealing a non-ignorable hyperfine coupling effect derived from the change in the nuclear magnetic moments of hydrogen atoms. The variations in emission vibrational peaks, investigated via both experimentation and computation, are strongly correlated with the changes in the kinetics of the high-frequency coupling modes exerted by site-selective deuteration. Moreover, deuteration suppresses triplet exciton-vibration coupling, which significantly reduces non-radiative decay rates and results in higher emission quantum yields. By effectively utilizing the site effect through selective deuteration, the photo-/electro-luminescent efficiencies of Pt-d¹_py are improved, along with its blue color purity. Furthermore, a device based on Pt-d¹_py demonstrates a twofold increase in the operational lifetime. We anticipate that these insights can enhance the development of organic materials at a subatomic level, leading to significant improvements in device performance.

Organic–inorganic hybrid halide perovskites exhibit exceptional properties, including prolonged charge carrier lifetimes, high photoluminescence quantum efficiency, and remarkable defect tolerance, demonstrating significant potential in optoelectronic applications like photoelectric detectors, light-emitting devices, and solar cells. Despite the high intrinsic carrier mobilities, their application in field-effect transistors (FETs) has not been well investigated. Three critical challenges currently hinder the development of high-performance hybrid halide perovskite FETs: ion migration, bulk/interfacial defects, and material instability. In the past few years, the application of halide perovskites as FET channel materials has been actively advancing, not only for the development of high-performance FETs showing stunningly improved mobilities, but also for fundamental investigation of charge transport mechanisms and structure–property relationships. This article comprehensively reviews recent progress in three-dimensional (3D) and two-dimensional (2D) organic–inorganic hybrid halide perovskite-based FETs. We discuss achievements and current challenges regarding device performance and stability issues of such hybrid materials and provide a general perspective on breaking through their bottlenecks and exploring future directions.

The rational preparation of efficient and durable electrocatalysts is the key to advancing the development of water electrolysis technology. Noble metal-based materials, such as Pt, Ru, and Ir, have excellent catalytic performance and stability. However, their high cost and low abundance require researchers to explore effective strategies to improve their utilization efficiency. Electrospinning is a facile synthetic method to prepare one-dimensional nanofibers with the desired composition and structure, especially carbon-supported metal-based electrocatalysts with a large specific surface area and high conductivity, through post-processing strategies. This review introduces the recent progress in electrospinning to prepare noble metal-based catalysts for water electrolysis. Specifically, we summarize various strategies for incorporating noble metals into electrospinning nanofibers, as well as their electrocatalytic performance towards hydrogen evolution, oxygen evolution, and overall water splitting. Finally, we propose the opportunities and challenges faced by electrospinning technology in the creation of water electrolysis catalysts, as well as the prospects for future development.

Based on crystalline polymorphism, we utilized a solvent-mediated crystal engineering strategy to synthesize three polymorphic copper-iodide clusters, 1 [Cu₄I₄(4-dpda)₄], 1-Tol [Cu₄I₄(4-dpda)₄·C₇H₈], and 1-PX [Cu₄I₄(4-dpda)₄·C₈H₁₀] (4-dpda = 4-(diphenylphosphino)-N,N-dimethylaniline), respectively. The polymorphic clusters not only exhibit significant differences in their crystal structures but also manifest remarkable changes in their room-temperature phosphorescence (RTP), high energy (HE)/low energy (LE) energy transfer barriers, and thermal quenching properties. Through comprehensive analysis of the single crystal structure, spectroscopic measurements and theoretical calculation, we elucidated the distinct mechanisms by which solvent-mediated crystal engineering enhances RTP performance. Furthermore, based on the significantly enhanced thermochromic effect, the potential of 1-Tol as a luminescent thermometer with dual-temperature-zone response characteristics was explored, achieving a notable improvement in sensitivity in the low-temperature region. In contrast, 1-PX broadened the response range of thermochromic sensing.

A zeolite catalyst, 2.0 wt%La₂O₃–SiO₂(IV)–0.1 wt%Pt–HBeta, with lamellar crystals was applied in the transalkylation of C₁₀ aromatics with 2-methylnaphthalene (2-MN) for the synthesis of 2,6-dimethylnaphthalene (2,6-DMN) under an H₂ atmosphere. The reaction pathways were accurately controlled by the precise cooperation among six aspects: (1) the synergy of excellent molecule diffusibility of the lamellar crystals with an appropriate shape selectivity at the pore openings narrowed by silicon deposition, capable internal acidity, and reactive participation of the surface active hydrogen species likely formed based on both metal Pt and Lewis acid sites resulted in remarkably enhanced transalkylation reactivity. (2) The teamwork of the inactive external surface covered by silicon and the space-limitation effect and properly assembled reactive sites (metal-Pt and acid) in the channels effectively avoided the naphthalene-ring loss. (3) The methylnaphthalene dealkylation and 2-MN isomerization were significantly weakened due to the reduced internal acidity resulting from La₂O₃ modification, selectively eliminating some strong acid sites. (4) The generation of multi-alkylnaphthalenes was greatly avoided, which was attributed to the space limitation and reasonable acid strength in the pores and shorter retention time of the diffusion reaction of lower alkylnaphthalenes in the lamellar crystals. (5) The pore-mouth shape-selectivity obviously enhanced the 2,6-DMN proportion in dimethylnaphthalenes (DMNs). (6) The strong capabilities of the modified lamellar crystals for resisting and accommodating coke with a reasonable catalytic hydrogenation and a providential internal acid strength ensured their excellent catalytic stability. As a result, a 2-MN conversion of >56.9%, a high DMN selectivity of >88.3%, and an enhanced 2,6-DMN yield of >19.3% were obtained during a 280 h on-stream reaction.

Materials that defy conventional lattice expansion at elevated temperatures and compression at high pressures hold immense potential for forefront functional applications, yet they remain unexplored. We present a rhenium-loaded zeolitic-A framework (Re-ZTA) that co-exhibits negative thermal expansion (NTE) and exceptional negative volumetric compressibility (NVC)-two rare, counterintuitive properties. These exotic phenomena manifested by Re-ZTA are ascribed to the occupation of the guest moieties, NH₄ReO₄ and NH₄NO₃, on the surface and within the pores. While the intrinsic NTE of the guest moieties and their anchoring effect on the bridging oxygen atoms of Re-ZTA trigger the tetrahedral rotation to facilitate the NTE behaviour until 205 °C, the progressive intrusion of the guest moieties into the pores from the surface of Re-ZTA is responsible for the observed switching from conventional compression to NVC above a critical pressure of 1.4 GPa. The framework structure was irreversibly amorphized at 4.6 GPa due to the accumulation of pressure-induced structural disorder, while the same was evident at a temperature beyond 205 °C due to the local instability of the framework. Remarkably, isothermal high-pressure diffraction studies at 70 °C and 130 °C exhibited the unexpected loss of NVC to typical compression owing to the thermal degradation of guest moieties while demonstrating enhanced structural stability by minimizing the structural disorder. These findings position Re-ZTA as a promising candidate for next-generation functional materials that offer tunable thermo-mechanical response under extreme conditions, paving the way for contemporary materials exhibiting simultaneous NTE, exceptional NVC and temperature-induced switching for structural, electronic and energy-related applications.

The electroreduction of CO₂ to methanol constitutes an attractive strategy for sustainable energy storage and carbon recycling. Methanol is not only a versatile chemical feedstock but also a liquid energy carrier compatible with existing infrastructure. However, the multi-step proton–electron transfer process and competing reaction pathways significantly limit methanol selectivity and production rates. This review provides a critical overview of recent progress in CO₂-to-methanol electro-conversion, including both direct CO₂ reduction reactions and indirect CO reduction reactions. We focus on mechanistic insights, emphasizing key intermediates such as CO*, CHO*, and CH₃O*, and identify structure–activity relationships through operando characterization and density functional theory calculations. The discussion spans a wide range of catalyst platforms, from molecular complexes, single-atom catalysts, and nanoclusters to alloy materials, and explores strategies such as tandem catalysis and interface engineering to increase selectivity and efficiency. We further explore developments in gas-fed flow cells and membrane–electrode assemblies that enable high-rate, stable operation. Finally, we highlight current limitations in catalyst design and system integration and outline emerging strategies to enable scalable and carbon-neutral methanol electrosynthesis.

Color-tunable fluorescence and phosphorescence have aroused great attention owing to their potential applications in display and lighting. However, achieving both color-tunable singlet fluorescence and triplet phosphorescence emission in single-chromophore polymers is still challenging. Herein, we develop two monomers (2-PTZ-BSe and 3-PTZ-BSe) with benzoselenidiazole at the 2- and 3-positions of phenothiazine (PTZ), and then photopolymerized them with NIPAM to obtain a series of polymers (2-PPTZ-BSe and 3-PPTZ-BSe). The resulting polymers present excitation wavelength, feed ratio and photopolymerization time-dependent color tunable fluorescence. Moreover, excitation wavelength, feed ratio and delay time-dependent phosphorescent emissions with lifetimes of hundreds of milliseconds are achieved for the polymers. By taking advantage of this color-tunable singlet and triplet emission feature, color-tunable and standard white electroluminescence with CIE coordinates of (0.35, 0.34) are obtained using the same chromophore in different polymers.