ACS Materials Letters最新文献

Defect passivation, relying on the interaction between passivators and the perovskite lattice, effectively improves the photoelectric performance of perovskite solar cells. Nevertheless, the principles for designing passivators, such as tuning molecular configuration and electrostatic potential, can sometimes be invalid even with those widely reported functional atoms and groups, showing an uncovered missing factor in current passivating mechanisms. Herein, by carefully comparing the isomerism of passivators, we unearth that the spatial position of functional atoms on the passivators plays a key role in determining their passivating capabilities. We find that the passivation becomes stronger when the spacing of functional atoms matches that of lead ions in between the neighboring lattice. Interestingly, by utilizing such a strategy, we achieve strong passivation from a passivator even with weak electrostatic potential. Eventually, we stepwise increase the device performance from a baseline of 22.74% to 23.30%/23.88%/24.60% with improved device stability, showcasing the advantage of optimizing molecular spatial configuration for passivators.

Severe burn wounds accompanied by infections associated with multidrug-resistant (MDR) bacteria are increasingly prevalent. However, infections and inflammatory storms occurring in the early stages of healing frequently lack effective interventions, which then disrupt subsequent normal healing events, ultimately resulting in suboptimal healing outcomes. Unfortunately, currently multifunctional hydrogel dressings are mostly focused on a single stage of the healing process (inflammatory or proliferative phase), failing to optimally orchestrate the immune microenvironment and tissue regeneration, which limits their clinical applicability. In response, we customized a GelMA-based hydrogel repair system involved in the whole healing process to promote tissue regeneration in a fine-tuned immune milieu. The combination of formulas demonstrated efficacy in alleviating the hyperinflammatory infiltration of wounds and stimulating neovascularization, hair follicle regeneration, and collagen deposition during the proliferative stage. Our dual-response hydrogel system presented an innovative strategy for refractory wound management, matching the clinical exigencies.

Developing efficient catalysts for the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells is challenging due to high power density and durability requirements. Subnanometer clusters (SNCs) show promise, but their fluxional behavior and complex structure–activity relationships hinder catalyst design. We combine density functional theory (DFT) and machine learning (ML) to study transition metal-based subnanometer nanoclusters (TMSNCs) ranging from 3 to 30 atoms, aiming to establish structure activity relationship (SAR) for ORR. Subdividing the data set based on size and periodic groups significantly improves the accuracy of our ML models. Importantly, the ML model predicting the ORR catalytic performance is validated through DFT calculations, identifying 12 promising catalysts. Late group TMSNCs exhibit enhanced ORR activity, reflected in a noticeable shift toward Au/Ag metals on the volcano plot. This underscores the importance of investigating late group TMSNCs alongside Pt for the ORR. ML accelerates TMSNC design, surpassing computational screening and advancing catalyst development.

Circularly polarized luminescence (CPL), an emergent technique to study excited state optical activity, is recently finding vast applications in diverse fields. The research focus has been to develop facile strategies to overcome the low luminescence dissymmetry exhibited by molecules and materials. We herein demonstrate a host–guest approach to achieve intense chiral luminescence in a series of achiral porphyrin nanostructures through their self-assembly with a chiral gelator. Efforts focused toward formulating a structure–property correlation revealed that modulating the host–guest interactions is critical to the generation as well as tuning of the CPL activity. Luminescence dissymmetry as high as 0.015 could be achieved through a judicious design strategy. The applicability of the as synthesized nanohybrid as a potential chiral light emitting device is demonstrated by coating the nanocomposite onto an LED surface.

Electrocatalytic water splitting is pivotal for advancing the hydrogen economy, yet conventional stable-phase catalysts are constrained by rigid crystal structures and electronic states, leading to fixed active sites, limited adaptability, and sluggish kinetics. Metastable materials emerge as promising alternatives due to their structural flexibility and tunable electronic properties; however, their dynamic regulatory mechanisms remain underexplored. This review uniquely offers a comprehensive analysis of metastable catalysts, emphasizing how factors such as size, phase structure, electronic properties, defects, and interfaces significantly enhance catalytic performance. By dissecting a range of materials (metals, alloys, oxides, sulfides, nitrides, and hydroxides), we elucidate precise modulation strategies that improve efficiency and stability. Practical applications highlight their superior adaptability and activity compared to traditional catalysts. Addressing key challenges and technical bottlenecks, this review provides innovative insights and strategic directions for optimizing metastable materials, thereby advancing efficient water splitting and sustainable energy conversion technologies.

Selective separation of acetylene (C₂H₂) from carbon dioxide (CO₂) and ethylene (C₂H₄) remains a significant challenge in the field of gas separation. Non-thermally driven separation technology based on metal–organic frameworks (MOFs) offers an efficient and environmentally friendly approach. Herein, a Ni-based anionic MOF (iMOF-1A) was employed for gas separation for the first time. The differential recognition of various gas molecules is enhanced by suitable pore sizes, accessible aromatic rings, and cations outside the framework. Experimental results demonstrate that iMOF-1A exhibits exceptional uptake ratios for C₂H₂/CO₂ (2.27) and C₂H₂/C₂H₄ (1.48), which surpass those of most previously reported MOF materials. Furthermore, the ideal adsorbed solution theory (IAST) selectivity calculations display a promising theoretical separation performance, which is supported by molecular simulations. Breakthrough experiments further validate that iMOF-1A not only effectively separates C₂H₂/CO₂ and C₂H₂/C₂H₄ mixtures but also exhibits excellent separation performance and humidity stability for C₂H₂/C₂H₄/CO₂ ternary mixtures.

Metal–organic frameworks (MOFs) boast high crystallinity, porosity, and tunability, making them highly promising materials for various applications. However, most MOFs are intrinsically electrical insulators, limiting their use in electronic and energy technologies. Electrically conductive metal–organic frameworks (EC-MOFs) have emerged as a subclass of MOFs that overcome such limitations by imparting electrical conductivity while preserving the advantageous properties of conventional MOFs. This advancement expands the potential applications of MOFs to include electrocatalysts, capacitors, energy storage devices, chemiresistive sensors, field-effect transistors, and electrochromic devices. However, the challenges associated with processing solid-state materials, such as MOFs and the fabrication options for optimal devices, are often overlooked. This Review focuses on the recent advancements in EC-MOF applications, emphasizing chemical design principles and state-of-the-art fabrication techniques. We aim to provide insights into designing and fabricating EC-MOFs for targeted applications and inspire further advancements that bridge chemistry and practical devices, unlocking the full potential of EC-MOFs.

Violet organic light-emitting diodes (OLEDs) hold promise for advanced applications, yet achieving simultaneously high efficiency and color purity remains challenging. This study presents a rational design of violet emitters by establishing a through-space charge transfer (TSCT) framework that enhances high-level reverse intersystem crossing (hRISC) for the effective utilization of triplet excitons. Two TSCT emitters, BO-MX-ICz and tBO-MX-ICz, are tailored with a weak donor and acceptor bridged by 9,9-dimethylxanthene in a face-to-face stacking arrangement. These emitters show narrow violet photoluminescence (PL) with a high efficiency. Their OLEDs exhibit high-color-purity violet electroluminescence (EL) with peaks at 406 and 408 nm, a full width at half-maximum (fwhm) of 25 nm, and maximum external quantum efficiencies (η_ext,maxs) of 4.61% and 5.03%. Additionally, as hosts for green multiresonance (MR) emitters, they deliver narrow EL spectra and excellent η_ext,maxs up to 34.36%. This molecular strategy could advance high-performance short-wavelength emitters for optoelectronic devices.

Coordinatively unsaturated sites (CUS) within MOFs are crucial in determining the sorbent selectivity by acting as the strongest binding sites for guest molecules. This study elucidates the thermodynamics of solvent binding to CUS by using Raman spectroscopy while varying solvent ratios to measure their competitive binding. The experimentally obtained solvent relative binding free energies correlate with the theoretical enthalpies computed via density functional theory but are even better predicted by the electrostatic potential minimum of the solvents. The experimental determination of guest binding energies at the metal site provides an approach for predicting behavior in mixed solvent systems and highlights the molecular properties that are required for the activation of CUS-MOFs.

Here, we report the solvent-induced polymorphism in [Cu₁₅(PET)₁₃(TPP)₆][BF₄]₂(Cu₁₅) (TPP = triphenylphosphine, PET = 2-phenylethanthiol), and double-helical assembly of the [Cu₁₈H(PET)₁₄(TPP)₆Cl₃] (Cu₁₈) nanocluster (NC) from reaction intermediates. Both copper NCs have an intrinsically chiral triple-stranded helicate metal core, unlike traditional copper NCs with a polyhedral-based kernel. The chiral structure of Cu₁₅ resembles an enantiomeric pair in the unit cell. Moreover, Cu₁₈ has a three-layered 3D chirality of a sandwich constructed of sulfur-bridged copper NCs aligned in a top-middle-down configuration. Furthermore, the Cu₁₈ NC self-hierarchically assembles into a complex double-stranded helix secondary structure sustained by noncovalent interactions. Electrospray ionization mass spectrometry (ESI-MS), density functional theory (DFT), and X-ray photoelectron spectroscopy (XPS) were utilized to validate the single-crystal X-ray diffraction (SCXRD) data. Overall, this study provides an interesting example of polymorphism, chirality, and hierarchical double-helical assembly of NCs, allowing for extensive understanding of complicated structures at the atomic level.