Science China Materials最新文献

Chiral conjugated polymers with controlled mesoscopic helicity are gaining attention for enantioseparation and asymmetric catalysis. However, achieving on-demand chirality and processability remain challenging. Herein, we exploit supramolecular coordination polymers formed by Mn²⁺ and chiral phenylglycine derivatives (L-/D-16PhgCOOH) as templates, using m-phenylenediamine as the monomer to synthesize chiral poly(m-phenylenediamine) (PMPD). In the Mn²⁺-templated system, the PMPD’s handedness is opposite to the molecular chirality of L-/D-16PhgCOOH, while in the Mn²⁺-free system, the PMPD handedness aligns with that of the template molecule. This method allows for helicity switching of chiral polymers within a single chirality template system. The introduction of Mn²⁺ is demonstrated to disrupt and reconstitute the supramolecular interactions in the co-assembly, influencing subsequent supramolecular stacking patterns. Carbonizing the resulting PMPDs directly produces chiroptical active nitrogen-doped carbonaceous nanomaterials that inherit the original helicity. Moreover, incorporating F-127 into the polymerization system enhances the aspect ratio of PMPDs, facilitating their delicate processing into chiral self-supporting two-dimensional films and three-dimensional foams. With abundant Lewis basic sites, these chiral polymers offer versatile platforms for novel chiral host-guest interactions.

The weakness of visible and near-infrared light penetration depth limits the application of photodynamic therapy (PDT) in deep-seated tumors. Based on the high penetrability of X-rays, X-ray-induced PDT (X-PDT) is a promising new method for treating deep-seated tumors. However, it requires the development of suitable X-ray-induced sensitizers that could employ X-ray energy to produce reactive oxygen species (ROS) efficiently. In this study, a novel X-ray-induced sensitizer (NanoSRF) was developed through a microemulsion method, in which copper iodine cluster compound Cu₂I₂(tpp)₂(2,5-dm-pz) (CIP) and rose bengal (RB) worked as scintillator and photosensitizer, respectively. CIP was synthesized by a simple mechanical grinding method, and subsequently folic acid (FA)-modified albumin was introduced to enable its alliance with RB. NanoSRF exhibited excellent dispersion stability and generated a large amount of ROS under X-ray irradiation. The results of in vitro studies demonstrated its high selectivity for FA receptor-positive cancer cells. Following systemic administration, NanoSRF accumulated in H22 tumors of xenograft-bearing mice, and X-ray irradiation (5.46 Gy) induced a significant inhibition rate of 96.7% in tumor growth. This study pioneers the use of copper iodide cluster as a scintillator in X-PDT, presenting new possibilities for designing scintillators with exceptional X-ray absorption and efficient X-PDT capabilities.

With the strict control of sulfur content in fuels, oxidative desulfurization (ODS), a promising desulphurization technology, needs to be continuously developed. In this study, we integrated multiple approaches (fabricating a porous structure, increasing phosphomolybdic acid (PMo) loading, improving amphiphilicity, and enhancing the intrinsic activity of PMo using a reductive framework) into PAF-54 carriers to improve ODS catalytic ability. The catalytic performance suggested that PAF-54 was not simply used as a carrier for PMo by physical integration. During the binding process, electron transfer between PAF-54 and PMo formed Mo⁵⁺ with superior catalytic activity. Owing to the presence of PAF-54, the catalytic activity of PMo as the active component qualitatively improved to achieve rapid and efficient desulfurization. More importantly, we found that other nitrogen-rich porous organic polymers can also reduce some of Mo⁶⁺ in PMo during loading, and its formation mechanism was investigated. This work provides a feasible strategy for designing highly efficient DOS catalysts.

Extreme ultraviolet lithography (EUVL) and electron beam lithography (EBL) are considered to be crucial lithography techniques utilized in the fabrication of nanoscale semiconductor devices. However, the industry currently faces a scarcity of EUV photoresists that meet the increasingly challenging standards in terms of resolution, sensitivity and roughness. Metal oxo nanoclusters have garnered significant interest in the field of EUV photoresist due to their relatively stronger absorption cross-section for extreme ultraviolet light and lower dimensions. In this study, we utilize a heterometallic nanocluster strategy by a combination of titanium and zirconium metals to investigate their solubility, assess the suitability of various developers, and evaluate their performance in electron-beam and EUVL, as well as study their etch resistance for pattern transfer. We demonstrate that R-4 is able to get a critical dimension (CD) of 25 nm at low doses under EBL, as well as 50 nm resolution at EUVL with a remarkable sensitivity of 19.7 mJ cm⁻². This study offers an efficient heterometallic method for optimizing the lithographic performance of metal oxo nanocluster photoresists, which can benefit the development of commercially viable next-generation EUV photoresists.

Conductive hydrogels have garnered considerable interest for their applications in wearable electronic skins, owing to their superior properties. Nevertheless, challenges persist, including low sensitivity, poor cyclic stability, and limited tolerance to extreme conditions. This study develops a novel liquid metal-based conductive hydrogel with a dual cross-linked polyacrylic acid (PAA) matrix, employing both “soft” coordination and “hard” covalent cross-linking mechanisms. This hybrid network is formulated using guar gum (GG)-stabilized gallium (Ga) droplets, which catalyze the copolymerization of vinyl-hybrid silica nanoparticles (VSNPs) and acrylic acid (AA). The resultant Ga³⁺ ions interact with carboxyl groups in the PAA, forming soft coordination links that enhance the hydrogel’s rapid gelation. The incorporation of VSNPs significantly enhances the hydrogel’s elasticity, toughness, and low-temperature resilience without glycerol. Notably, its intrinsic moldability, adhesion, and self-healing properties are retained. Applied as a strain sensor, this hydrogel demonstrates a high gauge factor (GF) of 17.4, responsive time of 250 ms for both activation and recovery, an ultra-low detection limit of 0.1%, and excellent durability over 800 cycles at 100% strain. Short-term immersion in a glycerol solution (20 min) further augments its stretchability to 2688% and GF to 28.1 across a strain range of 1325%–1450%, broadening its operational ranges to 0–1450% at −18°C. Prolonged exposure (4 h) also improves water retention and high-temperature resistance, making this hydrogel a promising material for sustainable, high-performance wearable electronics.

The interface is of paramount importance in heterostructures, as it can be considered as a device in accordance with Kroemer’s dictum. In perovskite solar cells (PSCs), optimizing the interface between the perovskite layer and the hole transport layer is known to be an effective method for enhancing PSC device performance. Herein, a metal ruthenium complex coded as C101 is introduced to the perovskite (CsPbI₂Br)/hole transport layer (PTAA) interface as a “charge driven motor” to selectively extract holes from CsPbI₂Br and then transfer them to PTAA, minimizing the voltage loss in PSCs. More significantly, the introduction of C101 layer effectively passivates the surface of CsPbI₂Br film and reduces the defect density of CsPbI₂Br film due to the covalent bond between the CsPbI₂Br and the–C=O group in C101. The photovoltaic performance of CsPbI₂Br PSCs is enhanced by 23.60% upon the introduction of C101 interfacial layer, with the champion CsPbI₂Br PSC exhibiting a power conversion efficiency of 14.96% in a reverse scan, a short-circuit current of 15.84 mA·cm⁻², an open-circuit voltage of 1.15 V, and a fill factor of 82.03%. Additionally, the introduction of C101 simultaneously enhances the humidity tolerance of CsPbI₂Br PSCs.

Thermal softening is an inevitable process in the physical network. Polyurethane (PU), a typical commercial material, is constructed by physical networks, which undergoes the serious thermal decay on mechanical properties at high temperature. Herein, a physically cross-linked PU with a unique thermal stiffening behavior has been developed by incorporating B-N coordination with reversible B-O bonds. The B-N coordination can significantly improve the mechanical properties of the PU. The reversible B-O bonds (temperature dependent reversible transformation between B-OH and B-O-B) are conducive to constructing more multi-coordination macromolecular crosslinking points and more stable B-N coordination bonds at high temperature, endowing the PU with the special thermal stiffening behavior for the first time. Such thermal stiffening behavior compensates for the bond breakage and the network destruction caused by heat, significantly expands the rubbery plateau and delays the entire chain motion of the thermoplastic PU. As a result, the terminal flow occurs at a higher temperature up to 200°C. The modulus retention ratio of the materials is up to 87% even at 145°C, which is much higher than that of the existing PU elastomer with the physical network and even some covalent cross-link PU. Simultaneously, the physical network ensures the recyclability of the PU, and the thermal stiffening behavior is still obtained in recycled PU. This work provides a simple strategy to impart thermal stiffening behavior to the physically crosslinked PU, thereby significantly extending the operating temperature range of thermoplastic PU, which can potentially expand the scopes of PU in applications under harsh conditions.

Effective separation of photogenerated carriers plays a vital role in governing the efficiency of photo-electrocatalytic reactions. However, the advancement in enhancing the intrinsic carrier separation efficiency of semiconductors has shown limited progress. Herein, we reported the use of a magnetic field to improve the photoelectrochemical water splitting of a magnetic Co₃O₄/TiO₂ photoanode by boosting the photogenerated carrier separation efficiency. In the presence of the magnetic field, oxygen evolution reaction occurs with a high photocurrent density of 0.86 mA cm⁻² at 1.23 V versus V_RHE, and an applied bias photon-to-current efficiency of 0.342% at 0.61 V_RHE. Moreover, the photoanode maintains its oxygen evolution reaction for more than 400 h with photocurrent decays by ca. 10%. Observations made in this effort show that the enhancement of photo-electrocatalytic efficiency by a magnetic field is a consequence of the effect of the Lorentz force generated by the magnetic field on photogenerated carriers and ions near the Co₃O₄/TiO₂ photoanode, which improves the carrier separation efficiency and the bubble release rate. The results suggest that manipulating photoelectrode carriers by using a magnetic field is a promising strategy to design high-performance photoelectrochemical for water splitting.