Journal of Materials Chemistry C最新文献

Mn₂O₃ particles were synthesized via a hydrothermal process and subsequently coated with Co₃O₄ to develop Mn₂O₃–Co₃O₄ composite particles as a supercapacitor electrode material. X-ray diffraction (XRD) confirms that the samples are crystallized and contain both Mn₂O₃ and Co₃O₄ phases. Mn₂O₃–Co₃O₄ nanoparticles with 40 min of reaction time displayed the highest specific surface area of 15.67 m² g⁻¹. The electrochemical behavior of Mn₂O₃–Co₃O₄ electrodes was investigated using charge/discharge measurements, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) in a 1 M KOH electrolyte at room temperature. The specific capacitance (C_SP) of Mn₂O₃–Co₃O₄-40 min exhibits an excellent value of 1289.6 F g⁻¹ (an 81.8% increase compared to the uncoated Mn₂O₃). In addition, the corresponding nanoparticles give the highest energy density of 35.3 Wh kg⁻¹ at a power density of 394.5 W kg⁻¹. Mn₂O₃–Co₃O₄ electrodes show good specific capacitance retention of above 95% after 5000 cycles of continuous charge/discharge. The Co₃O₄ coating on Mn₂O₃ not only enhances electrical conductivity but also introduces multiple redox couples (Mn²⁺/Mn³⁺, Mn³⁺/Mn⁴⁺, and Co²⁺/Co³⁺), enabling rapid and reversible redox reactions. This synergistic effect significantly enhances charge transfer kinetics and overall electrochemical performance, indicating that the Mn₂O₃–Co₃O₄ nanoparticle is a highly promising electrode material for next-generation supercapacitors.

We designed and synthesized an imino-linked dansyl-based molecule, DHNB, which exhibits interactions with the hair color ingredient p-phenylenediamine (PPD) and its oxidative trimer, Bandrowski's Base (BWB), over other analytes tested. Variable interactions, such as intra- and inter-molecular hydrogen bonding and environment-responsive conformational dynamics, were observed, leading to contrasting responses amongst the most responsive analytes. DHNB exhibits Excited State Intramolecular Proton Transfer (ESIPT)-assisted Aggregation-Induced Emission (AIE) in MeOH : H₂O (10 : 90), which is utilized for the detection of hair color ingredients. The presence of BWB quenches the fluorescence emission of DHNB in MeOH : H₂O (10 : 90) at 497 nm, whereas in the presence of PPD, the emission at 497 nm is quenched, with simultaneous appearance of a new blue shifted band at 402 nm. Importantly, the successful detection of PPD in a commercial hair color sample underscores the practical applicability of DHNB. Furthermore, variations in the charge transport properties of DHNB in MeOH : H₂O (10 : 90) and upon interaction with BWB/PPD were observed via current–voltage (I–V) measurements, suggesting its strong potential as an electrical sensor device.

Studying the impact of aggregation-induced quantum interference on excited state dynamics is a challenging and critical problem for regulating the emission of room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF). We designed and synthesized TPCO molecules with RTP properties. Additionally, we cultured two crystals with similar molecular arrangements but different luminescence mechanisms: one exhibits monomer-like green RTP luminescence (G-form), and the other shows yellow TADF luminescence (Y-form). Experimental and theoretical studies demonstrate that both G- and Y-form crystals exhibit similar molecular arrangements, specifically an inversion-packed dimer structure. In Y-form crystals, the reduction of intermolecular distances leads to an enhancement of excitonic couplings. The positive singlet and triplet excitonic couplings of the inversion-packed dimer significantly increase the fluorescence transition dipole moment by a -fold factor, corresponding to the degree of aggregation. Additionally, the energy gap (ΔE_ST) decreases from G-form crystals to Y-form crystals. These effects collectively enhance TADF emission. Due to their similar molecular arrangements, the transition between G-form and Y-form aggregates can be readily achieved by applying pressure. The research findings contribute to a deeper understanding of the effects of aggregation on RTP and TADF mechanisms and offer novel design guidance for the development of high-performance smart materials.

Congratulations to our 2025 Journal of Materials Chemistry Lectureship runners-up: Prof. Xiaoli Liu and Dr Beatriz Martín-García.

The sodium iron hexacyanoferrate compound with chemical formula Na_2.04(2)Fe[Fe(CN)₆]·2.24(2)H₂O, also known as Prussian white (PW), contains disordered and dynamic water molecules that have a dualistic effect on its battery performance. Furthermore, the material exhibits severe strain when dehydrated, which over time diminishes the performance. To understand the complex role of water on the sodium ion conduction and the structural changes happening upon dehydration, local structural characterization is needed. Here, we report the first neutron total scattering study of PW. Reverse Monte Carlo (RMC) fitting reveals that local octahedral distortion of the nitrogen-bound iron octahedra contributes to the disorder of the framework. The strain observed in the dehydrated material comes from a combination of the Fe–N bond elongation and a disordered distribution of sodium throughout the larger structure. In the hydrated material, the sodium exhibits more order due to the presence of water, which constrains the sodium movement. However, the sodium ordering affects the orientation of the water molecules. In the low temperature P2₁/n phase, sodium orders into planes with the oxygen atoms in the water molecules being in the plane, while the hydrogen atoms are pointing away from the sodium plane. In the room temperature R phase, the sodium and water are less ordered despite similar frameworks. Sodium can take a wide range of positions, especially if no water molecule blocks its way, to obtain optimal bonding conditions. These results show that the relationship between sodium and water is co-dependent, and demonstrate that the local structure of framework materials has a crucial link to their properties.

Flexible electrode conductors are essential components for the next generation of flexible electronics. Although ultrathin (<100 µm) silver nanowires (Ag Nws) are particularly suitable for multilayer optoelectronic devices, they are limited by low chemical and thermal stabilities. Current embedding techniques, proposed to overcome these limitations, involve complex or multi-step procedures that limit scalability. This study reports a high-throughput, large-area embedding process using a fully roll-to-roll (R2R) system to fabricate mechanically robust and transparent conductive films. Ag NWs and polymethylmethacrylate (PMMA) were used as conductive and embedding materials, respectively, with swelling-induced activation to enable efficient embedding. The continuous R2R process comprised three sequential steps: PMMA coating, Ag NW deposition, and application of the embedding-active agent. The optimal PMMA molecular weight, drying temperature, and embedding agent concentration for improving interfacial bonding and mechanical durability were determined. The resulting Ag NW-embedded flexible conductive films exhibited excellent electrical and optical performance, with a sheet resistance of 176.1 Ω sq⁻¹ and an optical transmittance of 99% over a 100 cm² area. The films also demonstrated superior durability under repeated bending, taping, and peeling, maintaining stable conductivity. Mechanical reliability was further validated by fabricating flexible touch screen panels that remained fully operational under continuous bending and could be conformally attached to curved surfaces, such as the wrist. The proposed fully-continuous R2R embedding strategy offers a scalable and reliable route for producing high-performance flexible electrodes suitable for wearable and large-area electronic applications.

Electrides constitute a unique class of ionic compounds where electrons localized in lattice cavities/channels serve as discrete anions rather than being bound to atoms. Recent years have witnessed a surge of interest in magnetic electrides. This review systematically elaborates their discovery strategies, design principles, unique magnetic origin, electronic structures, exotic properties, and cross-domain applications. Distinct from conventional magnetic systems, their magnetic ordering originates from either spin-polarized interstitial anionic electrons (IAEs) or orbital electron moments, enabling room-temperature ferromagnetism, spin-Peierls transitions and so on. Property modulation reveals emergent topological states and quantum behaviors in selected systems, with cutting-edge research focusing on dynamic control of magneto-topological phase transitions via external regulations. Moreover, applications demonstrate transformative potential for quantum devices, sustainable energy, and catalysis—particularly through IAE-enabled electron transfer mechanisms that substantially enhance spintronic efficiency, ion storage capacity, and catalytic performance.

As the demand for extreme-temperature-pressure exploration grows, the pressure stability of relaxor ferroelectrics, the backbone of piezoelectric sensors, emerges as a decisive factor. Employing a diamond anvil cell (DAC) with in situ XRD, PLM, Raman, and UV-vis spectroscopy, we probe the pressure stability of Sm-doped 0.93Pb(Zn_1/3Nb_2/3)O₃–0.07PbTiO₃ (Sm-PZN–7PT) relaxor ferroelectric crystals. Detailed analysis reveals three phase transitions in Sm-PZN–7PT. Near the phase transition point, changes in the domain structure of Sm-PZN–7PT can be observed via PLM. These domain structural changes can serve as an indicator of concomitant variations in the material's ferroelectric properties and optical absorption characteristics. These findings provide valuable insights into the stability of relaxor ferroelectric materials and offer guidance for the development of piezoelectric sensor devices operable under extreme environments.

This study presents a cost-effective, solution-processable approach to emulating synaptic plasticity using a solution-processed metal oxide thin-film transistor (TFT) with a bilayer Li-ion-conducting gate dielectric of Li₅AlO₄ and Li₄Ti₅O₁₂. This bilayer gate dielectric configuration reduces the DC conductivity of the Li₅AlO₄ film by three orders of magnitude, effectively reducing the gate leakage current of the transistor by similar orders. Additionally, the fabricated TFT demonstrates an ON/OFF ratio of 7.1 × 10³ with a saturation carrier mobility of 0.62 cm² V⁻¹ s⁻¹ and a subthreshold swing of 242 mV decade⁻¹. Additionally, this TFT shows high endurance in transfer characteristics over 100 consecutive cycles. Synaptic testing reveals that the device can successfully mimic short-term plasticity by applying various gate signals. Furthermore, paired pulse facilitation (PPF) is observed, fitting well with a double-exponential decay function. The transition from short-term plasticity (STP) to long-term plasticity (LTP) is also demonstrated, alongside potentiation-depression events. These potentiation-depression data are then used for artificial neural network simulations. Using a simple feed-forward neural network, the device achieves a pattern recognition accuracy of 92% with a mean loss of 0.3. A confusion matrix for numbers 0–9 further confirms the high accuracy of the device in recognizing these digits with the highest probability.

In this research, a terahertz temperature-controlled switch (TCS) composed of VO₂ and Cu is proposed to achieve reversible state switching. When VO₂ acts as an insulating phase, the TCS is in the “on” state, exhibiting a transmittance greater than 0.8 in the 4.47–7.92 terahertz (THz) frequency range. The operating bandwidth and transmission efficiency are 3.45 THz and 90%, respectively. When VO₂ is converted to its metallic phase, the TCS goes into the “off” state, attaining an absorption exceeding 0.9 within the 3.65–7.56 THz range. It has a bandwidth of 3.91 THz. During this state, the TCS implies nearly infinite absorption in shielding efficiency, with reflection shielding less than 1 dB. Furthermore, the TCS has a 79% overlapping operational bandwidth between its two states. High technological tolerance in its fabrication process guarantees reliable performance at any polarization angle and within a 30° incidence angle range. Through dynamic switching within a constrained spectral range, these qualities allow the TCS to execute time-division multiplexing (TDM) of different signals in the same frequency band. As a result, the TCS offers far more opportunities for use in communication systems.