Materials Chemistry Frontiers最新文献

The potential therapeutic benefits of reactive oxygen species (ROS) have garnered significant interest in the field of anti-tumor research. Chemodynamic therapy (CDT) serves as a common method for the treatment of tumors, and it employs Fenton/Fenton-like reactions to transform hydrogen peroxide (H₂O₂) into highly cytotoxic ROS. However, the single treatment mode, relatively low catalytic efficiency of CDT reagents, and insufficient endogenous H₂O₂ production limit its anti-tumor activity. To address these issues and inspired by the concept of metal-coordinated nanomedicine, we designed and prepared multifunctional palladium-based nanoparticles (Pd@RB@LAP NPs). The nanoparticles were synthesized by coordinating palladium ions (Pd²⁺) with Rose Bengal (RB) and subsequent loading of β-lapachone (LAP). LAP could produce a large amount of H₂O₂ through the quinone–hydroquinone–quinone redox cycle catalyzed by the NQO1 enzyme [NAD(P)H: quinone oxidoreductase 1] overexpressed at the tumor site. Pd²⁺ acted as a catalyst which could convert H₂O₂ into hydroxyl radical ˙OH, and RB as a photosensitizer under light illumination could also generate ROS (¹O₂). The oxidative stress created by the excess ROS could increase the NOQ1 level and further promote ROS generation, thus a positive feedback loop was created. Both in vitro and in vivo experiments provide clear evidence of the outstanding CDT efficiency and tumor growth suppression achieved by the Pd@RB@LAP NPs. This nanoplatform offers a simple but efficient paradigm for ROS-mediated tumor therapy.

Wide bandgap (WBG) perovskites are a key component of perovskite-silicon and all-perovskite tandem solar cells, which provides an effective way to exceed the efficiency limit of single junction solar cells. However, the small perovskite grain size and large defect density of WBG perovskites suppress the further improvement of the device power conversion efficiency (PCE). In this work, we offer a grain regrowth and defect passivation (GRDP) strategy to inhibit the nonradiative recombination loss at the perovskite grain boundary and in bulk simultaneously. Introducing guanidine thiocyanate (GuSCN) by post-treating the perovskite film can address this issue. GuSCN promotes the regrowth of perovskite grains and makes the grain size of perovskites larger than 1700 nm, thus reducing the defect density of perovskite solar cells (PSCs) by one order of magnitude. Consequently, a MA-free opaque WBG PSC achieves 20.92% PCE with excellent stability, maintaining 95.4% of its initial PCE after 3384 hours in N₂. Furthermore, we fabricated a four-terminal perovskite-silicon tandem solar cell and the champion device obtained 27.16% PCE. This work provides an effective way to improve WBG PSCs’ performance, facilitating the commercial application of tandem solar cells.

Owing to the unique properties of high porosity, outstanding chemical stability, and designable structures, vast applications of covalent organic frameworks (COFs) have been explored in a wide range of areas including energy storage, catalysis, gas separation, etc. Nevertheless, from the perspective of electrochemical sensing, the conductivity of COFs is not satisfactory. Here, a two-dimensional (2D) hybrid nanosheet combining a COF, a supramolecular host, and nanomaterials was constructed by assembling cucurbit[8]uril (CB8) onto the surface of the COF, and achieved in situ growth of uniformly dispersed AuNPs with the aid of the modulation effect of CB8 to synergistically enhance the sensing performance. By taking advantage of the abundant active loading sites and large specific area of the 2D-COF, excellent conductivity of AuNPs, and host–guest binding ability of CB8, the prepared COF/CB8/AuNPs is utilized to modify the glassy carbon electrode (GCE) as an advanced electrochemical sensor for simultaneous detection of structurally similar analytes, e.g. antineoplastic agent 5-fluorouracil (5-FU) and RNA base uracil (U) using differential pulse voltammetry, achieving detection limits down to the nanomolar level (e.g. 0.037 and 0.074 μM for 5-FU and U, respectively) and the physiologically relevant linear detection range within the sub-micromolar window. Impressively, the prepared COF/CB8/AuNPs/GCE sensor is considerably robust in complicated biofluids, allowing for detecting 5-FU and U in unprocessed native synthetic urine (SU) and whole fetal bovine serum (FBS), which remained highly challenging for electrochemical sensors. This study elucidates the integration of COFs with supramolecular host systems, paving the way for the development of advanced electrochemical sensors for rapid and onsite detection in pharmaceutical diagnostic applications.

Azobenzene is one of the most commonly used photochromic molecules, but is rarely used as a fluorescence probe in materials chemistry, due to its efficient photoisomerization providing competition for consumption of light energy. In this study, an azobenzene-containing ammonium surfactant was designed for fabricating an ionic cellulose material through an electrostatic complexation with carboxymethyl cellulose. Based on the AIE effect of the azobenzene motif, the cellulose material exhibited fluorescence. Furthermore, in aqueous conditions, the self-assembly of this cellulose material could be well regulated by effecting azobenzene isomerization under UV/Vis irradiation, which resulted in a remarkable change in the fluorescence intensity. As compared to the commonly used UV-Vis absorption, the fluorescence change of azobenzene was found to provide a more sensitive indication for tracking the dissolution and precipitation of the ionic cellulose-surfactant assemblies in aqueous conditions. This work has provided a useful strategy for fabricating photoresponsive fluorescent biomaterials based on azobenzene, opening a new opportunity for detecting drug-loading materials.

Polymer electrolytes have garnered considerable interest as a promising substitute owing to their exceptional mechanical flexibility, and appropriate interfacial compatibility with electrodes. However, the realization of economically viable and industrially scalable solid-state batteries with an elevated energy density and reliable cycling life remains a formidable task. The integration of high-voltage cathodes presents additional challenges, such as polymer electrolyte decomposition, consequential gas discharge, and the formation of an unstable solid–electrolyte interphase (SEI) layer on the lithium metal anode. These issues significantly impact the battery's cycling life and safety, necessitating profound attention towards enhancing the electrochemical stability of polymer electrolytes. Within this comprehensive review, we explore the problems arising from the evolution of the electrolyte/cathode and electrolyte/anode interfaces (e.g., electrochemical decomposition of the electrolyte, reverse cation catalysis, degradation products, etc.), and propose corresponding interfacial remediation strategies (e.g., in situ polymerization, inorganic coatings, etc.). Finally, we describe the persistent challenges and future perspectives aimed at providing strategies for the development of innovative polymer electrolytes capable of realizing high-performance lithium-metal batteries.

Organic polymers such as poly(ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) have attracted attention as thermoelectric materials, but charge-transfer complexes have not been explored sufficiently though these materials show very high conductivity and even superconductivity. Here, the power factors of representative organic metals and superconductors are estimated down to low temperatures. Several metallic conductors show power factors comparable to that of PEDOT:PSS (3 μW cm⁻¹ K⁻²), when the metallic conductivity is maintained down to low temperatures. In particular, Cu(DMDCNQI)₂, where DMDCNQI is dimethyldicyanoquinonediimine, exhibits a power factor as large as 95 μW cm⁻¹ K⁻² and a Peltier conductivity of 3.7 A cm⁻¹ K⁻¹ at around 36 K, which are comparable to those of conventional inorganic thermoelectric materials. Since this is attributed to the participation of the Cu flat band and the resulting three-dimensional energy band, the use of metal complexes is a promising strategy to explore high-performance thermoelectric materials. Thermoelectric power has been evaluated from the band structure, but conductivity anisotropy is calculated, and the relaxation time is estimated by the combined use of the observed conductivity.

Supersensitive and fast X-ray imaging is of great importance in medical diagnosis, industrial flaw detection, security and safety inspection, and frontier science exploration. As the core of detection devices, new generation scintillators require small self-absorption capacity, short fluorescence lifetime, simple film-making protocol, excellent stability and non-toxicity. Herein, a new type of lead-free organic silver halide TPPAgX₂ (TPP = C₂₄H₂₀P and X = I, Br, and Cl) is rationally developed with a large Stokes shift (176 nm) and ultralow photoluminescence decay (3.8 ns lifetime). It achieves an ultrafast fluorescent response that is the best among all the Pb-free perovskite scintillators. Temperature-dependent PL and DFT calculations together confirm that TPPAgCl₂ follows an emission mechanism in which a triplet exciton can be rapidly upconverted via thermal activation. A series of TPPAgX₂-based flexible scintillator films were fabricated and tested. A detection limit of 0.447 μGy_air s⁻¹ was obtained for TPPAgCl₂, which is one order of magnitude lower than the medical X-ray diagnosis requirement. In addition, it exhibits a superior X-ray imaging resolution of 11.87 lp mm⁻¹. The excellent performance and simple preparation methodology are expected to be potentially applicable for large-scale manufacturing.

Type I photosensitizers (PSs) used in photodynamic therapy (PDT) offer advanced capabilities because they can generate cytotoxic reactive oxygen species (ROS) through electron transfer, even in hypoxic environments. However, this process is more challenging compared to the type II process via energy transfer. Herein, we present a facile and effective strategy to regulate the proportion of the two types of PSs by converting type II PSs to type I PSs through the introduction of heterocyclic rings. Three tetraphenyl-1,3-butadiene (TPB) derivatives were synthesized, each incorporating a different “bridge” molecule: benzene (TPP), thiophene (TPS), and furan (TPO), forming typical D–A structures. Compared with TPP, the electron-rich heterocyclic derivatives TPS and TPO produce more ROS, with type I ROS accounting for a higher proportion. This enhancement is attributed to the lone pair of electrons in the heterocyclic rings, which enhances the intersystem crossing and electron transfer. Systematic and detailed experimental and theoretical calculations prove our findings: (yield of ROS)_TPO > (yield of ROS)_TPS > (yield of ROS)_TPP, and (proportion of type I ROS)_TPO > (proportion of type I ROS)_TPS > (proportion of type I ROS)_TPP. This strategy not only provides a pathway for developing new PSs, but also lays the foundation for designing pure type I PSs.

The electrocatalytic nitrogen reduction to ammonia reaction (eNRR) can use clean energy and catalyst materials to convert N₂ to NH₃ under relatively mild conditions, but how to design and synthesize electrocatalysts has been the focus of eNRR research. Metal–organic frameworks (MOFs) are a class of crystalline porous materials with a high specific surface area, high porosity and a designable structure, and show great potential as new electrocatalysts. Designing and synthesizing MOFs with high stability and high conductivity, and optimizing the adsorption energy of MOFs with nitrogen and intermediates are the key to improve the electrocatalytic performance. Hence, five Co-MOFs with a similar structure were designed to investigate the effect of small changes in the organic ligand structure on nitrogen reduction performance. Among them, the Co-MOF based on the thiazole ligand shows the best eNRR performance, with the highest NH₃ yield (51.30 μg h⁻¹ mg_cat⁻¹) and Faraday efficiency (29.2%) at −0.4 V vs. RHE. This study can provide theoretical guidance for the design and development of high-performance eNRR electrocatalysts in the future.

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