Journal of Materials Chemistry C最新文献

Indium phosphide quantum dots (InP QDs) have garnered significant attention as promising alternatives to cadmium-based QDs due to their low toxicity and high photoluminescence efficiency. However, the full width at half maximum (FWHM) of red-emitting InP QDs synthesized via aminophosphine-based methods remains approximately 45 nm, significantly limiting their application in high color gamut display technologies. In this study, we used indium(I) chloride (In(I)Cl) and tris(dimethylamino)phosphine (P(DMA)₃) as precursors to synthesize red-emitting InP QDs, combined with HF etching to significantly enhance their optical performance. The resulting InP QDs exhibited a narrow emission spectrum with a FWHM of 38 nm, the narrowest reported value for red-emitting InP QDs synthesized using aminophosphine precursors, approaching the FWHM of red QDs synthesized from silicon-based phosphines. Comprehensive kinetic studies of both reaction and growth processes revealed that the In(I)Cl precursor demonstrates substantially reduced reactivity. In(I)Cl initially undergoes disproportionation to form In(III) species prior to participating in transamination reactions. This unique reaction not only reduces the overall reaction rate but also enables a sustained and stable supply of In monomers, thereby prolonging the growth period and ultimately achieving a narrower FWHM. Low-temperature photoluminescence spectroscopy and X-ray photoelectron spectroscopy revealed that HF etching facilitates surface passivation by forming InF₃ as a Z-type ligand, while HF effectively eliminates surface dangling bonds and decomposes polyphosphate impurities, resulting in core-only InP QDs with an exceptional quantum yield (PLQY) of 80%. This study provides valuable insights and guidance for future research and applications of InP systems.

Circularly polarized organic light-emitting diodes (CP-OLEDs) have emerged as key candidates for next-generation display and security technologies; however, simultaneously achieving high device efficiency and pronounced chiroptical activity continues to pose a significant challenge. Paracyclophane (PCP), which exhibits a unique planar chiral structure, has been explored as an important scaffold for constructing efficient circularly polarized luminescent (CPL) active materials. This review summarizes recent developments in PCP-based CPL emitters and offers a thorough comparison with other chirality inducing analogues. Furthermore, it highlights strategies for incorporating PCP into emissive cores to induce and enhance circular polarization. Key molecular design approaches, including donor–acceptor systems, MR-TADF frameworks, and chiral perturbation methods, are discussed in relation to their impact on photophysical properties, dissymmetry factors, and device performance.

Flexible pressure sensors with a wide detection range and high stability are essential to realize reliable tactile sensing. Although dielectric microstructures can endow capacitive pressure sensors with excellent sensing sensitivity, how to realize reliable micro-structured dielectric layers is still an important issue to be solved. This paper presents a method for fabricating polydimethylsiloxane/multi-walled carbon nanotube (PDMS/MWCNT) dielectric layers with oriented MWCNTs utilizing an electrohydrodynamic printing method, thereby achieving a wide detection range and good stability for flexible capacitive pressure sensors. The synergistic effect of MWCNT orientation and printed microstructure within the dielectric layer enables the sensor to exhibit excellent mechanical and sensing performance in the detection pressure range of 20 Pa–150 kPa. The sensor shows excellent linearity in the pressure range of 60 kPa with a sensitivity of 0.1821 kPa⁻¹. The sensor shows excellent sensing accuracy with a response time of about 120 ms under 10 kPa pressure, and its performance does not degrade after 2.5 h of continuous cyclic pressure loading/unloading, showing excellent sensing stability. Furthermore, the application demonstration of real-time monitoring of arterial pulse signals from different physiological parts of the human body and immediate transmission of encrypted information verifies the sensor's potential for use in wearable electronic devices.

Phase engineering is pivotal for tailoring the properties of materials, enabling on-demand modulation of their physical properties. Two-dimensional transition-metal dichalcogenides (2D-TMDs) exemplify this potential, as their diverse polymorphs can be selectively stabilized to satisfy specific application requirements. Among them, ReS₂ naturally crystallizes in the 1T″ phase and exhibits pronounced in-plane anisotropy, offering unique opportunities for anisotropic electronic applications. Here, based on density functional theory (DFT) calculations, we report a hole-injection-driven phase transition from the semiconducting 1T″ phase to the metallic 1T′ phase in ReS₂. We find that hole doping stabilizes the metastable 1T′ phase and renders it energetically favorable. Ab initio molecular dynamics simulations further reveal the 1T″–1T′ transition dynamics, showing that a stable transition occurs at a doping level of approximately 9.5 × 10¹⁴ cm⁻². The underlying mechanism is attributed to the hole-doping-induced reshaping of the potential energy surface (PES), whereby the structure at the PES minimum gradually converges to the 1T′ configuration with increasing doping. The directional driving force generated by this PES evolution manifests as collective atomic displacements along coherent-phonon coordinates. The phase transition proceeds predominantly along the eigenvectors of two soft phonon modes in the doped 1T″ phase. This work establishes a microscopic framework for the semiconductor–metal transition in ReS₂ under hole doping and offers new avenues for phase-controlled crystal engineering toward advanced electronic applications.

Lanthanide-doped nanocrystals capable of color-tunable upconversion luminescence have attracted significant attention. However, current research primarily focuses on complex multi-layered core–shell architectures, making the structural design simplification for achieving tunable upconversion emission a persistent challenge. Here, leveraging the superior optical properties of double perovskites, we propose a simplified core–shell model (Cs₂NaYF₆:Er³⁺@Cs₂NaYF₆) to achieve orthogonal upconversion luminescence of Er³⁺ under different excitation wavelengths. Red-green switchable upconversion luminescence can be realized under dual-channel selective NIR wavelength (980 nm and 1550 nm) excitation, which is attributed to the distinct cross-relaxation rates of Er³⁺ under different excitation modes. Moreover, the coating of an inert shell further enhances the emission intensity (∼220-fold) by suppressing energy migration to surface quenching centers. This excitation-wavelength-gated upconversion luminescence modulation is successfully applied in information encoding and decoding based on the optical logic gate. These findings provide valuable insights for simplifying the design of tunable upconversion in core–shell nanostructures, offering significant potential for advanced information security applications.

Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) are promising candidates for next-generation electronic devices owing to high mobility, low processing temperature, and optical transparency. However, their vulnerability to high-energy proton irradiation severely limits device stability in radiation environments. This study presents a strategy for enhancing the proton irradiation tolerance of IGZO TFTs through hydrogen doping. Hydrogen was introduced into IGZO films by post-annealing in a 5% H₂/95% Ar atmosphere and quantified by elastic recoil detection (ERD) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Upon 5 MeV proton irradiation at a dose of 10¹³ cm⁻², the hydrogen-doped IGZO TFTs exhibited excellent radiation stability, with a threshold voltage shift of only −0.5 V. Depth-profiled X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS) revealed that hydrogen doping suppresses the formation of oxygen vacancies and promotes the conversion of O–H to M–H bonds after proton irradiation, relative to undoped devices. These results suggest a dual mechanism: hydrogen passivates oxygen vacancies through site occupation, followed by M–H bond formation, and compensates for irradiation-induced excess carriers via conversion of O–H bonds to M–H bonds. This simple hydrogen annealing approach provides a practical and effective route to highly reliable, radiation-hard oxide semiconductor devices.

The research focused on developing an optimal synthesis pathway for 3- and 4-amino/iodo derivatives of 1,8-naphthalimides, which are important reagents for obtaining new 1,8-naphthalimides derivatives with beneficial optical properties. During this work, the reactivity of individual compounds was discussed, which is primarily influenced by the position of substitution in the naphthalimide ring. In this respect, it was shown that amine derivatives substituted at the 4-position are characterized by lower basicity, which may explain their lower reactivity, for example in condensation reactions. The amine derivatives were used in condensation reactions with aldehydes to obtain derivatives containing an imine bond (–NC–), while iodo derivatives were used in Suzuki coupling reactions to obtain derivatives with a carbon–carbon bond (–C–C–). For the obtained compounds, the basic optical properties (UV-Vis, PL, quantum yield, emission lifetime, aggregation, etc.) were studied, comparing both the bond type (–C–C– vs. –NC–) and the site of substitution (3- vs. 4-posision). The properties of the obtained derivatives were analyzed and discussed and supported by appropriate theoretical calculations (DFT). Compounds with a –C–C– bond exhibited more intense emission than derivatives with a –NC– bond, which results from the photoinduced electron transfer (PET) from nitrogen atom to the naphthalimide ring in the imines studied. A bathochromic shift in emission was observed increasing solvent polarity for pyrene and naphthalene derivatives. Spectroscopic studies (¹H NMR, absorption and emission) of derivatives with the –NC– bond were also carried out in various solvents: weakly polar (dichloromethane) and polar (acetone, dimethyl sulfoxide) with the addition of trifluoroacetic acid in order to analyze the PET inhibition as well as hydrolysis processes, which are responsible for the increase in emission observed for the investigated imines. UV-vis and ¹H NMR studies of the imines in the presence of trifluoroacetic acid showed that the imine derivatives at the 4-position are more susceptible to hydrolysis than those substituted at the 3-position. Moreover, the analyzsed compounds with a –C–C– bond exhibited aggregation-induced emission (AIE) or aggregation-induced blue-shifted emission (AIBSE), whereas compounds containing an imine bond (–NC–) showed aggregation-caused quenching (ACQ).

While the clusteroluminescence (CTE) of cucurbiturils has been established, a systematic understanding of how their macrocyclic structure dictates the emission efficiency remains elusive. Herein, we explore how polymerization degree and substituents affect the clusteroluminescence (CTE) of cucurbiturils. All tested Q[5–8] and methyl-substituted Q[6] crystals exhibited excitation-dependent fluorescence and phosphorescence. Q[6] and Q[7] exhibited superior multicolor emission, while methyl substitution weakened this property. Structural and theoretical analyses revealed CTE's dependence on self-assembled unit number and packing density.

Reservoir computing (RC) provides a training-efficient alternative to recurrent neural networks by fixing recurrent weights and training only a linear readout. In hardware, physical reservoirs harness intrinsic device dynamics to supply the three requisites for temporal computation: nonlinearity, short-term memory, and resulting high-dimensional state richness. This review summarises RC fundamentals and maps device requirements onto materials properties including domain nucleation, hysteresis, depolarisation-driven volatility, and multiscale relaxation. We survey representative ferroelectric platforms, including hafnia-based ferroelectric field-effect transistors (FeFETs), ferroelectric tunnel junctions (FTJs), and ferroelectric thin-film transistors (FeTFTs), together with their antiferroelectric variants. These devices inherently support nonlinear input–state mapping, tunable fading memory, and rich intermediate states. Implementation strategies include multiplexing and single-device reservoirs, evaluated against metrics for memory capacity and energy–latency–accuracy. Emphasis is placed on complementary-metal-oxide–semiconductor compatible HfO₂ for scalability, fast switching, and low-voltage operation. Reliability and variability are reframed as resources through interface and defect engineering. Ferroelectrics emerge as energy-efficient reservoirs for robust temporal inference at the edge.

Two-dimensional MXene-derived chalcogenides offer a versatile platform for tailoring quantum states. Using first-principles calculations, we investigate the M₂S (M = 3d, 4d) monolayers and their hydrogen-functionalized derivatives to enhance superconductivity and explore competing charge density waves (CDW). Pristine phases exhibit modest superconducting transition temperatures (T_c), but full hydrogenation induces three distinct adsorption geometries (α, β, γ), significantly boosting T_c. Within the McMillan–Allen–Dynes framework, β-Ru₂SH₂ and β-Tc₂SH₂ show promise, while fully anisotropic Migdal–Eliashberg calculations predict T_c values of 20–47.75 K, reaching 51 K in γ-Ru₂SH₂ under 1% compressive strain. Notably, γ-Tc₂SH₂ and α-Ru₂SH₂ exhibit CDW instabilities driven by strong electron–phonon coupling, distinct from conventional Fermi surface nesting. These findings highlight hydrogen functionalization and strain as powerful strategies for designing high-T_c superconductors with coexisting quantum orders in MXene-derived systems. While T_c values depend on computational approximations, the robust trends and interplay of CDW and superconductivity offer actionable insights for experimental synthesis and exploration of novel quantum materials.