Materials Chemistry Frontiers最新文献

The direct spinning of carbon nanotube (CNT) aerogels via floating catalyst chemical vapour deposition (FCCVD) provides a robust pathway for translating nanoscale CNT assemblies into continuous macroscopic sheets. Scaling this process to larger reactor diameters is essential for improving throughput and enabling industrial-level production; however, such scale-up introduces complex transport, catalytic, and process-control challenges that must be systematically understood and optimised. In this study, we investigate the synthesis of CNT sheets in a large-diameter (100 mm) FCCVD reactor, with a focus on resolving key limitations associated with scalability and continuous sheet formation. The influence of precursor delivery rates, carrier and fuel gas composition, catalyst formulation, residence time, and operating pressure on CNT sheet growth has been comprehensively examined. Extensive characterisation, including Raman spectroscopy, SEM, TEM, XPS, TGA, and computational fluid dynamics (CFD) analyses, provides detailed insight into the structural, chemical, and thermal features of the resulting CNT networks and the underlying mechanisms governing aerogel formation in an enlarged reaction volume. Through systematic optimisation of process parameters, we demonstrate the successful production of macroscale CNT sheets with a yield of 4.0% and a carbon conversion rate of 7.5 mg min⁻¹, representing a significant improvement over conventional reactor geometry. These results establish critical guidelines for process intensification and highlight the practical viability of large-diameter FCCVD reactors for high-efficiency, high-productivity CNT sheet manufacturing.

Photocatalytic water splitting for hydrogen production represents a highly promising technology for converting and storing solar energy, with photocatalytic active materials serving as a crucial component in a photocatalytic system. In this study, organic photovoltaic materials were employed as photocatalysts, and Förster resonance energy transfer (FRET) was introduced to induce efficient photocatalytic hydrogen evolution. A mixture of D18 and QX-1 served as the base system, with the third component, IT-M, incorporated to facilitate FRET. The prepared thin film, when illuminated in a photochemical reaction system, achieved an average hydrogen evolution rate of 7430 µmol h⁻¹ m⁻² over 8 hours—15% higher than that of the D18:QX-1 control group (6460 µmol h⁻¹ m⁻²). This demonstrates that FRET effectively enhances the photocatalytic hydrogen evolution performance of organic photovoltaic materials, marking a significant advancement in the design of efficient organic photocatalysts.

Two examples of molybdate phosphates, K₆Mo₈PO₂₉OH·H₂O and K₆Mo₅P₂O₂₃·7H₂O, were designed and synthesized using a hydrothermal method, introducing strongly distorted [MoO₆] octahedral groups. K₆Mo₈PO₂₉OH·H₂O crystallizes in the centrosymmetric space group Cmcm, where each [PO₄] combines [Mo₄O₁₅] and [Mo₄O₁₄(OH)] groups to form a unique [Mo₈PO₂₉(OH)] cluster. K₆Mo₅P₂O₂₃·7H₂O crystallizes in the non-centrosymmetric space group P2₁2₁2₁, where two [PO₄] link [Mo₅O₂₁] groups to form a closed hollow ellipsoidal [Mo₅P₂O₂₃] cluster. They possess wide experimental band gaps of 3.57 and 3.34 eV, respectively. Compared to K₃PO₄, the introduction of strongly distorted [MoO₆] octahedral groups enhances their birefringence from 0.006 to 0.127 and 0.077@1064 nm (about 21 × and 11 × K₃PO₄), with the source of the birefringence being dominated by the contribution of strongly distorted [MoO₆] octahedral groups. The relationship between its structure and optical properties is analyzed based on first-principles calculations. This work effectively enhances the birefringence properties of phosphate crystals by introducing highly distorted [MoO₆] groups, providing insights for designing and synthesizing ultraviolet optical crystal materials with superior performance.

Photochromic materials are important for smart windows for energy management. Transition metal oxide (TMO) semiconductor photochromic materials are limited by the need for a dedicated hole scavenger to promote photogenerated electron accumulation. This limits the integration of TMOs in devices for practical uses. Moreover, the hole scavenger is exhausted in time, thus limiting the long-term operation. Here, we demonstrate the photochromic performance of doped titanium dioxide (TiO₂) nanoparticles, which not only show increased photochromic performance when compared to TiO₂ nanoparticles but are also capable of photo-darkening without the presence of a dedicated hole scavenger. This opens up real-life practical applications in passive photochromic and photochargeable devices without the need for intricate heterostructures or pseudocapacitors.

Solid-state lithium batteries (SSLBs) hold promise for next-generation energy storage due to their high safety and energy density. However, challenges such as poor interfacial contact, high interfacial impedance, and lithium dendrite growth limit the practical application of garnet-type Li₇La₃Zr₂O₁₂ (LLZO) and its derivatives (Ta-doped Li₇La₃Zr₂O₁₂, LLZTO). This study investigates the effects of incorporating LiGaO₂ (LGO) into LLZTO to enhance grain-boundary bonding, reduce activation energy, and suppress lithium dendrite growth. LiGaO₂ powder was synthesized via a solid-state reaction and mixed with LLZTO to form composite ceramics. Structural characterization using XRD and SEM confirmed that LGO stabilizes the cubic garnet structure of LLZTO without forming impurity phases. The LLZTO-1 wt% LGO composition, sintered at 1260 °C, exhibited superior performance with a room-temperature ionic conductivity of 0.951 mS cm⁻¹ and a relative density of 96.3%. Electrochemical impedance spectroscopy shows that the interfacial resistance decreases by ∼50% (from ∼30 Ω to ∼15 Ω). The hybrid full cell retains 99.3% capacity after 200 cycles at 0.8C, showcasing practical applicability. These results highlight the effectiveness of LGO-mediated grain boundary engineering in improving the electrochemical performance of LLZTO-based solid electrolytes, paving the way for their large-scale preparation and application in SSLBs.

The transition to sustainable energy requires efficient storage technologies to manage the intermittency of renewables like solar and wind. Electrochemical devices such as supercapacitors, lithium-ion batteries, and redox flow batteries depend heavily on ion-conducting membranes for ionic transport, selectivity, and stability. Traditional membranes, including Nafion, SPEEK, and PVDF, face challenges like thermal instability and limited conductivity. To address these issues, organic framework materials have emerged as promising alternatives. This review focuses on four main classes: metal–organic frameworks (MOFs), covalent organic frameworks (COFs), porous organic polymers (POPs), and hydrogen-bonded organic frameworks (HOFs). MOFs provide high porosity and tunability; COFs offer crystallinity and chemical stability; POPs support scalable synthesis and mechanical strength; and HOFs enable the fabrication of reversible, self-healing structures. This review explores synthesis methods, structure–property relationships, and electrochemical performance, outlining strategies to improve membrane functionality and durability in advanced energy storage systems.

Due to their excellent biocompatibility, outstanding water dispersibility, and multifunctional integration capability, carbon dots have emerged as highly promising materials for cancer phototherapy. In this study, nickel-doped carbon dots (Ni-CDs) were successfully synthesized via a one-step hydrothermal method, which enables efficient and uniform Ni incorporation within the carbon framework. Ni-CDs exhibit strong absorbance in the range of 840–1100 nm. They have a reactive oxygen species (ROS) production rate of 3.27% and a photothermal conversion efficiency of 61.33% under 1064 nm laser irradiation. The enhanced dual-mode performance can be attributed to Ni-induced nonradiative relaxation and improved electron transfer. They are the first reported nickel-doped carbon dots with synergistic therapeutic capabilities of PDT/PTT in the NIR-II region. In vitro and in vivo experiments demonstrated that Ni-CDs can effectively induce tumor cell death, with no significant toxic damage observed in normal tissues/organs. This study highlights the potential of Ni-CDs as a multifunctional nanoplatform for deep-tissue cancer treatment, providing a reference for the design of materials for the synergistic combination of photothermal and photodynamic therapy of deep tumors.

Efficient blue electroluminescent (EL) materials have been a continuing research topic for high-performance organic light-emitting diodes (OLEDs), particularly the blue emitters with the ability to utilize triplet excitons in their EL process. Herein, three donor–acceptor–donor (D–A–D) type blue fluorophores (mFS, pFS, and pPS) are systematically designed and synthesized by using diarylsulfones as acceptor cores (A) and the 1-phenyl-2-(m-tolyl)-phenanthroimidazole moiety as a π-conjugated donor (D). Different diarylsulfones (dibenzothiophene-5,5-dioxide (FS) and sulfonyldibenzene (PS)) are wisely functionalized with two donors at either meta- or para-positions. The photophysical studies and theoretical calculations verify that mFS, pFS, and pPS are blue hot exciton fluorophores with hybridized local and charge transfer (HLCT) states and decent photoluminescence quantum yields. They are effectively employed as non-doped and doped emitters in blue OLEDs with reasonable device EL performances. In particular, the doped mFS-OLED realized a deep blue emission (EL_max = 443 nm, CIE coordinates of (0.154, 0.088)) with a maximum external quantum efficiency (EQE_max) of 7.24%. Thereafter, a 2-stack white OLED is successfully fabricated using pPS as a sky-blue HLCT emitter and bis(4-phenylthieno[3,2-c]pyridinato-N,C2′)(acetylacetonate)iridium(III) (PO-01) as a complementary orange-yellow phosphorescent emitter. The white OLED achieves an EQE_max of 9.19% with CIE coordinates of (0.32, 0.31), a color-rendering index (CRI) of 79, and a correlated color temperature (CCT) of 6122 K. These results demonstrate the great potential of phenanthroimidazole–diarylsulfone-based fluorophores in developing blue organic multifunctional fluorescent materials and their OLED applications.

We present a combined experimental and theoretical investigation of the pressure response of the chlorine-based two-dimensional perovskite (PMA)₂PbCl₄. High-pressure synchrotron powder X-ray diffraction (HP-PXRD), photoluminescence spectroscopy (HP-PL), and density functional theory (DFT) calculations reveal that compression up to 5.45 GPa induces pronounced anisotropic lattice contraction and partial amorphization, while decompression reveals phase reversibility. The PbCl₆ octahedra remain mechanically rigid, with distortions accommodated by octahedral tilts, flattening, and migration of phenylmethylammonium cations (PMA⁺), leading to interlayer planarization and enhanced electron–phonon coupling. Elastic tensor analysis confirms moderate mechanical anisotropy and coexisting auxetic and conventional elastic responses. HP-PL demonstrates a pressure-driven crossover between narrow free-exciton emission (quenched by 1.84 GPa) and more resilient broadband self-trapped exciton emission (persisting up to 7.8 GPa with its maximum intensity at ∼4.5 GPa). Overall, the compression-driven structure–property evolution maintains broadband emission, which leads to increased nonradiative losses at higher pressures. The combined results establish (PMA)₂PbCl₄ as a mechanically robust, pressure-tunable broadband emitter with strong potential for stable optoelectronic applications.