Journal of Materials Chemistry C最新文献

A new small molecule acceptor, CH-TCl, featuring chlorothiophene-based terminal groups and a centrally extended core was synthesized and integrated into ternary organic solar cells. The resulting devices achieved a power conversion efficiency of 19.38%, surpassing the 18.67% of their binary counterparts. The incorporation of CH-TCl as a third component enhanced charge transfer, boosted the open-circuit voltage (V_OC), and improved the overall device performance. This study provides an effective strategy for optimizing ternary OSCs by introducing high V_OC acceptors.

Thermoelectric (TE) properties of layered Ge–Sb–Te compounds have received extensive attention owing to their decent TE performance with high electrical conductivity and low thermal conductivity. Here, we report the structure and TE properties of In-doped GeSb₄Te₇ compounds prepared by vacuum hot-pressing sintering. We determined that GeSb₄Te₇-based compounds exhibit site-occupational disorder due to Ge/Sb cation mixing and that In-doping in GeSb₄Te₇ compounds significantly lowers the thermal conductivity, enhances the Seebeck coefficient, and improves the power factor of pristine GeSb₄Te₇. Noticeably, the room-temperature power factor of the Ge_0.925In_0.075Sb₄Te₇ sample can be increased by 174% compared to that of the GeSb₄Te₇ sample. The optimized electrical properties and the suppressed thermal conductivity result in a maximal TE figure-of-merit of 0.62 achieved in Ge_0.925In_0.075Sb₄Te₇ at 750 K, which is about 41% higher than that of the pristine sample. Our theoretical calculations indicate that the band structure, the density of states, and the local crystal structure of GeSb₄Te₇ can be modified by the In-doping, which contributes to improving the TE properties of GeSb₄Te₇-based compounds. Our studies on the atomic-scale structure of GeSb₄Te₇ and the effect of In-doping on the TE performance are helpful to the configurational entropy design and the performance optimization of layered TE materials.

Designing composite electromagnetic wave absorption (EWA) materials with a strategic structure is a key approach to improve the EWA efficiency of SiC nanowires (SiC_NWs). In this study, SiC_NWs/reduced graphene oxide (SiC_NWs/RGO) composites with layered porous structures were successfully prepared using homemade SiC_NWs and graphene oxide (GO) using simple freeze-drying and heat treatment techniques. Then the EWA performance of SiC_NWs/RGO with different filling amounts (5 wt%, 15 wt% and 25 wt%) was investigated. A minimum reflection loss (RL_min) value of −47 dB at 12.7 GHz was achieved when SiC_NWs/RGO was filled with 5 wt% and the coating thickness was 2.2 mm. When the coating thickness was reduced to 2.0 mm, the effective absorption bandwidth (EAB) extended to 5.78 GHz (12.02 to 17.8 GHz), covering the entire Ku band. The outstanding EWA performance was primarily due to the layered porous structure, which facilitates multiple reflections and scattering of electromagnetic waves (EMWs). This structure not only lengthened the wave attenuation path but also worked synergistically with dielectric and conductive losses. The SiC_NWs/RGO composites prepared in this study are characterized by light weight, thin thickness and high absorption rate, enabling them to be particularly suitable for electromagnetic shielding in the field of livelihood and ecology.

Biointerface engineering is pivotal for the seamless integration of wearable sensors with skin, offering transformative potential in bioelectronics, personalized diagnostics, and human–computer interfaces. Nonetheless, creating high-performance biointerface materials that adhere effectively to the skin while simultaneously providing breathability and preserving mechanical compliance remains a formidable challenge. Here, we present a solvent-free, ion-conductive biointerface film fabricated via the physical crosslinking of soft polyethylene oxide with phytic acid. The resulting film exhibits excellent air permeability (1.89 ± 0.02 mg cm⁻² h⁻¹), self-adhesion (89.60 ± 1.45 kPa), and mechanical compliance (skin-compatible Young's modulus of approximately 0.42 MPa). Remarkably, the material can be recycled and reused over 10 times, and dissolved quickly in hot water at 60 °C, enabling facile reprocessing. We demonstrate its efficacy as a wearable sensor conformally attached to the knuckles, providing stable electrochemical signals that accurately track bending states. In addition, we demonstrate its application as a leaf patch for continuous monitoring of plant activity over 48 hours. These findings offer a sustainable and versatile platform for advancing the development of flexible wearable technologies.

As the dimensions of semiconductor devices continue to shrink and the complexity of the manufacturing process increases, metal interconnects that link different parts of integrated circuits have become a key factor in determining device performance, speed, and power efficiency. Until recently, copper (Cu) has been used as a metal interconnect material, but due to a sharp increase in resistance at sub-10 nm, ruthenium (Ru) is considered a promising candidate for advanced interconnect materials. In order to employ Ru as the interconnect material, it is necessary to secure adhesion characteristics with amorphous SiO₂, which is used as a representative insulator, but there is little understanding of the interfacial adhesion especially within an atomistic perspective. This study combines machine learning potential and steered molecular dynamics to provide atomic-level understanding of the adhesion properties of Ru/SiO₂ interfaces. It was found that the presence of hydroxyl groups on the surface of SiO₂ significantly affects the adhesion and the removal of hydrogen atoms from the hydroxyl groups is remarkably effective in increasing adhesion, even under excessive conditions. The analysis of the bonding characteristics between Ru and interfacial atoms of SiO₂ suggests that the degree of bonding between Ru and oxygen atoms is crucial for adhesion, and that the adhesion characteristics can be predicted through the bond order of interfacial atoms.

In this study, an atypical copper oxynitride (Cu_xO_yN_z) system was synthesized with tunable Cu–O–N compositions. Structural analyses using X-ray diffraction, Rietveld refinement, micro-Raman, and high-resolution transmission electron microscopy confirmed the presence of Cu–O, Cu–N, and metallic Cu phases in the Cu_xO_yN_z system. Physicochemical investigations revealed the distinct properties of O_rich-, N_rich-, and Cu_rich–Cu_xO_yN_z systems. The O_rich–Cu_xO_yN_z system exhibited enhanced stability in photocatalytic reactions, while the N_rich–Cu_xO_yN_z system displayed a broader optical response due to a lower bandgap energy compared to pure-CuO. The Cu_rich–Cu_xO_yN_z system, with its meta-stable Cu–N lattice, formed a plasmonic ohmic junction, facilitating efficient charge transfer and leading to enhanced photocatalytic activities. The photocatalytic dye degradation (in %), H₂ evolution (in μmol g⁻¹ h⁻¹), and NH₃ formation (in μmol g⁻¹ h⁻¹) over the O_rich–Cu_xO_yN_z system (∼95/963.6/495.8) were found to be superior compared to those over the N_rich–Cu_xO_yN_z (∼73/741.8/435.4) and bare oxide (∼62/418.3/270.2) systems. Unlike conventional bare or N-doped copper oxide materials, the synthesized copper oxynitride systems demonstrated synergistic properties, showing organized interactions among oxide, nitride, and metallic components. This research paves the way for a better understanding of the formation mechanism of atypical unary metal oxynitride systems and highlights their unique features as an emerging class of materials for energy and environmental applications.

Colloidal lithography offers a cost-effective and straightforward method for fabricating periodic arrays, utilizing colloidal spheres as microlenses to create patterns in a photoresist. However, the exposure depth remains a challenge. By utilizing PDMS to fill colloidal films, high-aspect-ratio photoresist nanopillars were employed as the structural basis for the successful fabrication of both metallic resonant type and non-metallic anti-reflective type broadband near-perfect optical absorbers. According to simulated light beams and the resulting photoresist patterns, the introduction of PDMS not only made the colloidal mask flexible and reusable, but also significantly increased the beam convergence depth, enabling the formation of high-aspect-ratio photoresist patterns. In simulations, the effective focused beam depth was sensitive to the film's refractive index, colloidal diameters, and ratios of the sphere diameter to periodicity of colloidal arrays, resulting in a depth of 2828 nm under optimal parameters. In experiments, photoresist arrays with pillar heights reaching up to 3374 nm and the corresponding depth-to-width ratio of 5.04 were achieved. Additional petal-shaped or octopus-shaped pillars were also created during PDMS-assisted lithography. A metallic absorber, based on the conformal Pt coating, achieved an average absorbance of up to 98.3% over the range from 400 nm to 1100 nm, with a minimum absorptivity of 96%. An all-dielectric optical absorber, employing photoresist nanopillars for impedance matching, exhibited an average absorptivity of 92.4% within the same wavelength range.

Copper(I) thiocyanate (CuSCN) is a unique wide band gap, p-type inorganic semiconductor with extensive opto/electronic applications. Being a coordination polymer, CuSCN requires processing by coordinating solvents, such as diethyl sulfide (DES). The strong interactions between CuSCN and DES lead to the formation of SCN⁻ vacancies (V_SCN), which are detrimental to hole transport. In this work, we rationally modify copper(I) thiocyanate (CuSCN) through the use of chemically compatible copper(I) halides (CuX, where X = Cl, Br, or I). On assessing the device characteristics of thin-film transistors employing CuX-modified CuSCN as the p-channel layer, adding 5% of CuBr is found to be the most optimal condition. The hole mobility is increased by 5-fold to 0.05 cm² V⁻¹ s⁻¹ while the on/off current ratio is also enhanced up to 4 × 10⁴. The drain current in the off-state does not increase whereas the trap state density is reduced, and the performance improvement can be attributed to the defect healing effect. Detailed characterization by synchrotron-based X-ray absorption spectroscopy reveals the recovery of the coordination environment around Cu, confirming that Cl⁻ and Br⁻ can effectively passivate V_SCN defects. In particular, CuBr further improves film uniformity and smoothness. The simple protocol based on common chemicals reported herein is applicable to the standard CuSCN processing recipe, which is currently applied across a wide range of electronic and optoelectronic devices.

Perovskite nanocrystals (NCs) offer exceptional optical properties but suffer from limited stability. Encapsulation with polymer materials is a promising approach to enhance their stability. However, traditional characterization techniques often fall short in providing a comprehensive understanding of the protection mechanism. We developed a high-throughput characterization platform based on nanoparticle arrays to investigate the protective effects of different polymers on CsPbBr₃ NCs. Using this platform, we found that polystyrene (PS) films, even at relatively thin thicknesses, significantly outperform thicker poly(methyl methacrylate) (PMMA) films in preserving NC photoluminescence. This suggests that the intrinsic properties of the polymer, beyond its thickness, play a crucial role in protecting NCs. Our findings provide valuable insights into the design and selection of effective polymer encapsulation materials for perovskite NCs.

Secondary electrons play a vital role in extreme ultraviolet lithography (EUV-L), as low-energy electrons (LEEs) induce the solubility switch of the photoresist via electron-induced reactions. However, optimizing EUV absorption at 92 eV and addressing the relatively long inelastic mean free path (IMFP) of LEEs, which can lead to pattern blurring, remain critical challenges. Here, first-principles calculations based on time-dependent density functional theory (TDDFT) are conducted to evaluate how chemical substitutions in metal and ligand sites affect both EUV absorption and the energy loss function (ELF) of LEEs in oxalate systems. Results highlight that atomic cross-sections alone are insufficient for optimizing photoabsorption, and electronic structure effects must be considered. Analysis of the ELF of LEEs reveals that iodine-containing systems exhibit a higher ELF at low energies, suggesting a reduced IMFP. Additionally, iodine incorporation shows potential to lower the band gap, which may further reduce the IMFP of LEEs in photoresists. These findings underscore the significance of electronic structure effects in EUV-L and demonstrate the value of first-principles calculations in optimizing photoabsorption and electron behavior for next-generation lithography applications.