Majid Moghadam

The aqueous instability of inorganic halide perovskites such as CsPbBr3 remains a critical barrier to their practical utilization in photoelectrochemical water splitting. Here, we employ surface engineering with zeolitic imidazolate frameworks (ZIFs) to simultaneously stabilize CsPbBr3 photoanodes and modulate their interfacial charge-transfer behavior. By systematically comparing Zn-based ZIF-8 and Co-based ZIF-9 overlayers, we distinguish hydrolytic protection from interfacial charge-transfer effects and demonstrate how the metal-node coordination environment governs photoelectrode performance. Although both framework coatings enhance surface hydrophobicity and effectively suppress moisture-induced degradation, they exhibit distinct electronic characteristics. ZIF-8 functions primarily as an insulating passivation layer that suppresses surface recombination but impedes hole transfer because of its high interfacial charge-transfer resistance. In contrast, the Co-based coordination network in ZIF-9 establishes a favorable interfacial heterojunction that lowers the interfacial charge-transfer resistance and facilitates hole extraction toward the oxygen evolution reaction. Consequently, the FTO/TiO2/CsPbBr3/ZIF-9 photoanode delivers a photocurrent density of 2.7 mA cm–2 at 1.23 V vs. RHE, representing an approximately 89% enhancement over the ZIF-8-modified counterpart (1.43 mA cm–2), while retaining more than 75% of its initial photocurrent after 7200 s of continuous illumination. These findings demonstrate that rational surface engineering with MOF overlayers provides a viable strategy for simultaneously enhancing surface protection and interfacial charge transport in perovskite-based photoelectrodes for solar fuel applications.

Halide perovskite nanocrystals are promising photocatalysts for CO2 reduction due to their strong light absorption, defect tolerance, and tunable excited-state properties, but their practical performance remains limited by tightly bound excitons, rapid charge recombination, and inefficient interfacial electron delivery. Here, we report an anthraquinone (AQ)-modified CsPbBr3 nanocrystal photocatalyst (CPB/AQ) in which the redox-active π-conjugated AQ ligand functions as an interfacial electron relay and molecular electric-field modulator. Experimental and theoretical analyses collectively reveal that AQ creates an additional interfacial charge-transfer pathway, strengthens the light-induced surface potential difference from 170 to 270 mV, and decreases the exciton binding energy from 44.05 to 40.74 meV. Consequently, CPB/AQ achieves a CO yield of 433.50 μmol g–1 within 3 h under AM 1.5G irradiation, 4.54 times that of pristine CPB, and maintains stable CO evolution during a 25 h test. Isotopic 13CO2 tracing verifies that CO originates from CO2 reduction, while in situ FTIR spectroscopy demonstrates enhanced CO2 adsorption/activation and accelerated formation of *COOH and *CO intermediates on CPB/AQ. This work highlights molecularly gated interfacial electric-field regulation as an effective strategy for overcoming charge-transfer bottlenecks in perovskite nanocrystal photocatalysis.

CsPbBr3 perovskite nanocrystals (PNCs) demonstrate exceptional photocatalytic potential in CO2 conversion through superior light harvesting and multi-exciton generation. However, their practical application is fundamentally hindered by structural instability that compromises carrier utilization. This study, using femtosecond transient absorption spectroscopy and temperature-dependent photoluminescence, reveals that dynamic coupling between hot carriers and lattice vibrations drives structural degradation via localized phonon excitations. To address this, we engineered indium (In)-anchored CsPbBr3 PNCs by targeted modification of surface Pb centers. The In-anchoring passivates defect-associated empty p-orbitals while prolonging the hot carrier lifetime by 98.86%. Furthermore, the introduced In atoms induce electronic localization, which suppresses phonon-driven lattice vibrations. As a result, charge separation and transport are dramatically enhanced, leading to a significant improvement in both CO2 reduction activity and stability. In contrast to CsPbBr3 PNCs, which completely deactivate within 20 h, In-anchored CsPbBr3 PNCs maintain stability over long-term operation for up to 60 h, while simultaneously exhibiting a 14.85-fold enhancement in CO yield. This study establishes a fundamental strategy for stabilizing perovskite photocatalysts by regulating hot carrier-lattice interactions, offering new insights into the design of high-performance CO2 reduction systems.

Nanostructured platforms have attracted significant attention as promising drug carriers due to their unique properties and therapeutic efficiency. This work aims to prepare three-dimensional flower-like iron-doped silver nanostructures (HFAg-Fe) and evaluate their potential as nanocarriers for Methotrexate (MTX), a first-generation anticancer and autoimmune drug. The HFAg-Fe were synthesized, modified, and characterized by FE-SEM, FT-IR, XRD, AFM, and elemental analyses. Drug loading and release were studied using UV–vis spectroscopy, showing an MTX loading capacity of 86% and pH-responsive behavior rapid release under acidic tumor conditions and slower release at physiological pH, potentially reducing side effects. Hemolysis and cytotoxicity assays indicated that HFAg-Fe/MTX possessed superior biocompatibility and anticancer efficacy compared to free MTX, while fluorescence microscopy confirmed efficient uptake by cells. Cell cycle analysis showed treatment-induced arrest, mainly at the S phase. X-ray micro-computed Tomography revealed significant tumor volume reduction and preferential accumulation of the nanocarrier at the tumor site. These findings highlight the potential of HFAg-Fe nanostructures as safe drug delivery systems, where 4-aminothiophenol serves as a linker to facilitate drug loading and release, potentially enhancing outcomes in cancer therapy.

Molecular wires represent a cornerstone of next-generation nanoelectronics, yet the design of highly efficient, short molecular conductors remains a significant challenge. In this study, we present a catalyst-free, green synthetic route for the preparation of anilino-1,4-naphthoquinone enaminone derivatives via aqueous-phase Michael addition between anilines and 1,2-naphthoquinone-4-sulfonic acid sodium salt. The reaction proceeds rapidly at room temperature, yielding products with excellent efficiency (96–98%) and exceptional purity, as confirmed by comprehensive spectroscopic characterization (FT-IR, UV-Vis, ¹H and ¹³C NMR, MS) and elemental analysis. Single-crystal X-ray diffraction further validated the molecular structures of representative compounds. Theoretical investigations using Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) provided deep insights into the electronic properties and charge transport behavior of these systems. Key analyses included cohesive energy calculations, UV-Vis exciton energy profiles, frontier molecular orbital energies (HOMO/LUMO), chemical reactivity descriptors (hardness, softness, chemical potential), and dipole moment variations under external electric fields (0-140 × 10^− 4 a.u.). Additionally, localized orbital locator (LOL) contours, electron density Laplacians, and current-voltage (I–V) characteristics based on Landauer theory were evaluated to assess charge transport efficiency. Comparative analysis reveals that extending the π-conjugation in a molecular system markedly improves its electronic properties, leading to lower energy gaps, enhanced conductance, and greater field responsiveness, which are critical for molecular wire functionality. Furthermore, this work combines sustainable synthesis with advanced computational modeling to offer a robust framework for the design and evaluation of short molecular wires for nanoelectronic devices.

Coordination polymers (CPs) can be used as supporting materials for enzyme immobilization to overcome limitations arising from mass transfer barriers, active site blocking, and low enzyme loading, as previously demonstrated, employing metal–organic frameworks (MOFs). We report on a new composite containing glucose oxidase (GOD) and ZIF-7-III (Zn(bIm)₂), focusing on three aspects: formation, optimization of catalytic properties, and application. The immobilization of GOD on ZIF-7-III at room temperature was systematically studied by varying the amount of GOD and the reaction time. ZIF-7-III/GOD composites were obtained, as confirmed by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). GOD incorporation significantly slows the crystallization of ZIF-7-III. The optimized composite exhibits relative catalytic activity of 98% at maximum enzyme loading, enhanced stability across a broad pH range (3 < pH < 9), and stability at elevated temperatures (up to 80 °C). Storage stability retains 66% activity after 60 days, which is important for possible applications. The use of the composite in an electrochemical biosensor for glucose detection was also demonstrated. Cyclic voltammetry and amperometric measurements were performed, demonstrating high repeatability (RSD −1. Notably, the sensor effectively detected glucose in human plasma samples, indicating its potential for real-world glucose monitoring.

This investigation focused on the design of an advanced polymeric scaffold that integrates Ethylcellulose (EC) and Polystyrene (PS) to fabricate four novel Metal-Organic Framework/Ethylcellulose-Polystyrene (MOF/ECPS) adsorptive membranes for the aim of water desalination. These membranes were created using in situ synthesis of ZIF-8, UiO-66-NH₂-EDTA, and UiO-66- NH₂ in the presence of electrospun ECPS nanofibers, along with ex-situ synthesis of MIL-125-NH₂/ECPS electrospun nanofibers. The NaCl removal performance of these nanocomposite adsorptive membranes was evaluated under ideal conditions. These conditions included starting NaCl content, intercalated MOF percentage, pH, temperature, dosage, and adsorbent contact time. The synthesized nanocomposites were successfully recycled 25 times without experiencing a significant reduction in adsorption capacity, except for MIL-125-NH₂, which showed a decrease after 18 recycles. In this investigation, four different kinetic models were utilized: Elovich, intraparticle diffusion, pseudo-first-order, and pseudo-second-order. Adsorption characteristics were found to be in line with pseudo-second-order kinetics. Analysis of the adsorption isotherm parameters using the Langmuir and Freundlich models revealed that the surfaces of UiO-66-NH₂/ECPS, UiO-66-NH₂-EDTA/ECPS, and ZIF-8/ECPS nanocomposites are heterogeneous and exhibit multilayer Na⁺ adsorption. In contrast, the adsorption of Na⁺ on the MIL-125-NH₂/ECPS nanocomposite follows a monolayer adsorption mechanism. Studies in thermodynamics demonstrate that adsorption occurs as an exothermic and spontaneous process that adheres to pseudo-second-order kinetics and isotherm models.