FlatChem最新文献

{"title":"A comparative study of non-vdW Hematene synthesized via different methods for its potential application in NO2 gas sensing","authors":"Sumit Kumar Choudhary ,&nbsp;Ujjwal Singh ,&nbsp;Ajay Agarwal ,&nbsp;Devendra Singh Negi","doi":"10.1016/j.flatc.2026.101056","DOIUrl":"10.1016/j.flatc.2026.101056","url":null,"abstract":"<div><div>Non-van der Waals (non-vdW) two-dimensional (2D) materials like Hematene, derived from non-layered structures such as α-Fe₂O₃, offer unique advantages over traditional van der Waals (vdW) materials like graphene, transition metal dichalcogenides (TMDs), and phosphorene. Unlike vdW materials that exfoliate along weak interlayer forces, Hematene originates from a strong, non-layered crystal structure, enabling distinct physicochemical properties including greater structural stability, tunable electronic behavior, and enhanced catalytic activity. Recognizing that synthesis methods play a crucial role in shaping these properties, this study systematically compares Hematene synthesized via chemical, microwave, and ultrasonic exfoliation techniques. The results show that chemical exfoliation yields thinner nanosheets with increased surface reactivity, which significantly enhance nitrogen dioxide (NO₂) sensing performance. Notably, the chemically exfoliated Hematene demonstrated a high response of 81% and a rapid response time of 10 s at 20 ppm NO₂ at an optimized operating temperature of 150 °C, outperforming both other exfoliation methods and many conventional vdW-based 2D sensors. These findings highlight the importance of optimizing synthesis strategies to tailor the properties of non-vdW 2D materials. Overall, this work positions Hematene as a promising candidate for high-performance gas sensors and a compelling alternative to traditional vdW materials in next-generation sensing applications.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"57 ","pages":"Article 101056"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147849530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineered 3D MXene- and GO-based Ag nanocomposites with enhanced stability and antibacterial performance","authors":"Amina Ben Ayed,&nbsp;Mina Masoudi,&nbsp;Mina Namvari","doi":"10.1016/j.flatc.2026.101052","DOIUrl":"10.1016/j.flatc.2026.101052","url":null,"abstract":"<div><div>Silver-containing systems are among the most promising antibacterial strategies. However, their practical efficacy is frequently compromised by the instability, aggregation, and uncontrolled oxidative dissolution of silver nanoparticles (AgNPs). This study explores the development of hybrid 3D systems utilizing graphene oxide (GO) and MXene nanosheets as functional scaffolds for stabilized AgNPs. 2D nanosheets were crosslinked with an organic silane, <em>N</em>, <em>N</em>′-bis(3-(triethoxysilyl)propyl)urea (Bis-urea), which performs both as a reducing agent for Ag⁺, confining their size and growth location, and inhibiting the aggregation of the 2D nanosheets. The resulting 3D nanocomposites exhibit a hierarchical architecture in which agglomeration of AgNPs is restricted by 2D nanosheets, while the intercalated silane linkers and AgNPs prevent restacking of GO and MXene nanosheets. The synthesized nanohybrids and nanocomposites were characterized using XRD, FTIR, Raman, TGA, SEM, TEM, and XPS to confirm every step of modification. Moreover, the zeta potential and size distribution were measured using DLS to provide insight into the surface charge and formation of nanocomposites. The zeta potentials were determined to be −23.13 mV and − 19.38 mV for the GO-based and MXene-based nanocomposites, respectively, both of which are more negative than that of Bis-urea/Ag (−18.46 mV). Antibacterial assays against <em>E. coli</em> and <em>S. aureus</em> revealed synergistic enhancement. Notably, MIC values of the MXene-based nanocomposites were reduced by 64-fold against <em>E. coli</em> and 125-fold against <em>S. aureus</em>, while the GO-based nanocomposites exhibited 16-fold and 8-fold reductions in MIC values against <em>E. coli</em> and <em>S. aureus</em>, respectively. At 1/2 MIC, over 90% reduction in colony forming unit (CFU) was observed, indicating a pronounced bactericidal effect of all samples. This performance stems from a combined mechanism: the “nano-knife” effect of the 2D edges inducing physical membrane disruption, complemented by localized oxidative stress and sustained Ag⁺ release from the embedded nanoparticles.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"57 ","pages":"Article 101052"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147951578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuning electronic structure of cobalt in cobalt-nitrogen-carbon catalyst via introducing oxygen group for efficient oxygen reduction to H2O2","authors":"Haonan Cui ,&nbsp;Jinyang Ma ,&nbsp;Jiaqi Xiang ,&nbsp;Xinyu Li ,&nbsp;Ou Zhuo ,&nbsp;Shanyong Chen","doi":"10.1016/j.flatc.2026.101055","DOIUrl":"10.1016/j.flatc.2026.101055","url":null,"abstract":"<div><div>Cobalt‑nitrogen‑carbon (Co-N-C) catalysts for the two-electron oxygen reduction reaction (2e⁻ ORR) toward H₂O₂ production typically suffer from insufficient selectivity. Herein, we introduce oxygen functional groups into Co-N-C via an oxidative treatment of the carbon substrate. This strategy effectively tunes the electronic structure of cobalt sites, suppressing the undesired 4e⁻ ORR and favoring 2e⁻ ORR. The optimized catalyst (Co-NOC) achieves an H₂O₂ selectivity of 98% at 0.4 V vs. RHE, and maintains &gt;90% selectivity over a wide potential range from 0.1 to 0.65 V vs. RHE. In a flow cell, it delivers a high H₂O₂ production rate of 101.5 mg cm⁻² h⁻¹ at −200 mA cm⁻² with a Faradaic efficiency of 94%. This work provides a new strategy for modulating the electronic structure of single-atom catalysts and deepens the understanding of the structure-performance relationship in 2e⁻ ORR.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"57 ","pages":"Article 101055"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147849529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graphite-lattice curvature engineering of iron-nitrogen-carbon nanosheets for efficient oxygen reduction reaction in proton exchange membrane fuel cells","authors":"Weiqi Liang,&nbsp;Lizhen Wen,&nbsp;Wanling Xiao,&nbsp;Cunhuai Yu,&nbsp;Ji Huang,&nbsp;Chengfu Tan,&nbsp;Pei Kang Shen,&nbsp;Zhi Qun Tian","doi":"10.1016/j.flatc.2026.101050","DOIUrl":"10.1016/j.flatc.2026.101050","url":null,"abstract":"<div><div>Unraveling the critical role of graphite lattice curvatures of carbon matrix in transition metal-nitrogen-carbon (M-N-C) for enhancing oxygen reduction reaction (ORR) is essential to construct non-precious metal-electrocatalyzed proton exchange membrane fuel cell (PEMFC). Herein, a salt-mediated strategy of tailoring Fe-N-C nanosheets with various graphite lattice curvatures was developed by pyrolyzing a newly designed Fe ion complexed amid-based polymer in a molten salt bath. Introducing the salt template in the synthesis facilitates the formation of 3D Fe-N-C nanosheets with highly exposed active sites and increases the graphite lattice curvatures of carbon matrix to optimize the electronic structure of Fe atom, thereby enhancing ORR performance. The Fe-N-C obtained with KCl featuring highly disordered and curved graphite lattices achieves a high acidic ORR performance with a half-wave potential of 0.805 V and only 20 mV decay after 30,000 cycles, which is much better than both the Fe-N-C prepared with NaCl with ordered and low curved lattices (0.783 V, 30 mV loss) and the Fe-N-C obtained without any salt having highly graphitic lattices (0.614 V, 123 mV loss). Meanwhile, it delivers a highest power density of 657 mW cm⁻² in PEMFC. Additionally, theoretical calculation reveals that compared with the planar graphite, the curved graphite lattice not only enhances the more electron accumulation on Fe, leading to a significant reduction of the overpotential of the rate-determining step of *OH, but also strengthens the Fe-N bond with a higher crystal orbital Hamilton population bonding value, thereby simultaneously promoting both the activity and durability of Fe-N-C for ORR. These results highlight new insights into boosting ORR of M-N-C through adjusting carbon matrix lattices.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"57 ","pages":"Article 101050"},"PeriodicalIF":6.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147849528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bismuth chalcogenide-Zincite nanocomposite for the determination of a potent bioactive flavonoid","authors":"Hemarani Annadurai ,&nbsp;Tse-Wei Chen ,&nbsp;Sivaprakash Sengodan ,&nbsp;Elayappan Tamilalagan ,&nbsp;Shen-Ming Chen","doi":"10.1016/j.flatc.2026.101007","DOIUrl":"10.1016/j.flatc.2026.101007","url":null,"abstract":"<div><div>A strong dietary flavonoid known for its anti-inflammatory, antioxidant, and newly discovered anti-cancer effects, quercetin (QR) has important effects on both plant defense systems and human health. For nutritional assessment, its quantitative detection is essential. For that we designed the Bi₂S₃@ZnO (BSZ) nanocomposite modified glassy carbon electrode (GCE) for this work and showed an excellent electrocatalytic activity towards QR oxidation. This is attributed to the synergistic effect between Bi₂S₃ and ZnO, which promotes charge transfer and provides an abundant number of active sites. The sensor exhibited an exceptionally wide linear range from 0.1 μM to 3362 μM and an ultra-low detection limit of 0.63 nM. For the accurate determination of QR in various food samples, the practical applicability was successfully demonstrated with excellent recoveries. This study reveals the potential of semiconductor heterojunctions in forward-looking electrochemical sensing systems in addition to establishing an adequate instrument for QR analyzing.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"56 ","pages":"Article 101007"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2D layered Co3O4/crystalline graphene nanocomposite: In-situ synthesis, Auger analysis, elemental mapping and fabrication of a flexible dopamine sensor","authors":"Rimpa Mondal ,&nbsp;Sk. Faruque Ahmed ,&nbsp;Nillohit Mukherjee","doi":"10.1016/j.flatc.2026.101010","DOIUrl":"10.1016/j.flatc.2026.101010","url":null,"abstract":"<div><div>An in-situ electrochemical deposition technique was utilized to develop Co₃O₄/crystalline graphene (Co₃O₄/cGr) nanocomposite 2D layered structure on indium oxide (ITO) coated polyethylene terephthalate (PET) flexible structure. Thorough characterizations of the deposited material have been carried out, interestingly that indicated the formation of crystalline graphene in the nanocomposite with an approximate layer count in the graphene stack within 18 and 20 and interlayer spacing of around 0.35 and 0.34 nm. The core-level ionization followed by non-radiative relaxation in Auger spectrum revealed the presence of mixed states of cobalt (i.e., Co(II) and Co(III)) in a spinel oxide structure, whereas, elemental mapping underscored well-distribution of cobalt, oxygen and carbon in the deposited film; that in turn refers to a highly active surface. On the other hand, electrochemical technique for the detection of neurotransmitters like dopamine can be a single-key solution to sensitive, selective and rapid determination of the analyte; where, such unique structural, compositional and surface features of the developed electrode material (Co₃O₄/cGr) could be well-contributing. Dopamine is a neurotransmitter that plays very important role in regulating human nervous actions and any imbalance in its abundance can cause severe issues like depression, hypertension, Parkinson's diseases and Schizophrenia, to name a few. This makes it very essential to detect the level of dopamine in human serum/plasma with best possible accuracy. So, in this work, the developed Co₃O₄/cGr nanocomposite was also explored for its possible application as an electrochemical dopamine sensor, and the results in terms of sensitivity, selectivity and reproducibility were quite encouraging.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"56 ","pages":"Article 101010"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth of MoS2 films with vertical flakes via oxidative post-treatment of Mo precursor layers","authors":"Carlos M. Monzón-Somazzi ,&nbsp;Sebastián E. García ,&nbsp;Karen E. Navarro-Gamarra ,&nbsp;Eduardo M. Patrito","doi":"10.1016/j.flatc.2026.101019","DOIUrl":"10.1016/j.flatc.2026.101019","url":null,"abstract":"<div><div>The sulfurization of pre-deposited Mo seed layers is a widely adopted method for synthesizing large-area MoS₂ thin films with uniform thickness. However, upon exposure to air, nanometric native oxide films are formed on the Mo surface. Despite the extensive work using thin Mo layers, the oxidation state of the precursor remains poorly characterized. In this study, we investigate the role of Mo precursor oxidation state on MoS₂ morphology using 10 nm Mo films on SiO₂/Si substrates sulfurized at 900 °C. Pretreatments of the Mo precursor layer included: freshly deposited Mo (having substoichiometric oxides), oxidative aging in air (yielding amorphous MoO₃), and reductive annealing in Ar/2% H₂ at 450 °C (producing Mo suboxides and MoO₂). Scanning electron microscopy revealed the distinct topographies of the resulting MoS₂ films: compact granular films from fresh precursors; vertical flakes with voids from aged precursors; and worm-like structures from reduced precursors. Spectroscopic ellipsometry modeling revealed the structure and thickness of the MoS₂ films: those prepared from fresh precursors exhibited a compact single-film structure with a thickness of 29.1 nm; films from aged precursors showed a single-film structure interspersed with void regions and a greater thickness of 41.6 nm; in contrast, films from the reduced precursor displayed a double-film structure comprising a compact inner film (12.4 nm thick) and a non-compact outer film (23.1 nm thick). We propose that the sublimation of amorphous MoO₃ and its subsequent redeposition as oxythiomolybdate complexes are key to the formation of vertically aligned platelets separated by voids. In experiments where mass transport to the gas phase was suppressed, the resulting MoS₂ films exhibited a smooth, compact morphology. MoS₂ structures with vertically oriented platelets showed significantly higher electrocatalytic activity for the hydrogen evolution reaction than compact MoS₂ films. This study demonstrates that the surface morphology of MoS₂ can be precisely controlled by tuning the oxidation state and crystallinity of the Mo precursor.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"56 ","pages":"Article 101019"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147400102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2D materials in photoelectrochemical cells: Opportunities for next-generation solar batteries","authors":"Rashida Batool ,&nbsp;Nazmina Imrose Sonil ,&nbsp;Muhammad Ahsaan Bari ,&nbsp;Adnan Khalil ,&nbsp;Nadeem Raza ,&nbsp;Mostafa E. Salem ,&nbsp;Muhammad Faizan Nazar ,&nbsp;Zaka Ullah","doi":"10.1016/j.flatc.2026.101012","DOIUrl":"10.1016/j.flatc.2026.101012","url":null,"abstract":"<div><div>The continuously increasing global demand for sustainable and efficient energy solutions has intensified the interest of researchers in photoelectrochemical (PEC) cells as promising devices for direct solar energy conversion and storage. However, typical PEC systems often bear crucial challenges, particularly limited light absorption, sluggish charge transport, and poor long-term durability. Recent advances in two-dimensional (2D) materials have brought transformative opportunities to meet these limitations owing to their exceptional optical, electronic, and surface features. This review systematically investigates the integration of 2D materials into PEC cells, focusing on their roles as conductive frameworks, interfacial layers, co-catalysts, photoanodes, and photocathodes. A comparative analysis of various 2D materials, including graphene and its derivatives, transition metal dichalcogenides (TMDs), MXenes, black phosphorus, and 2D metal oxides/nitrides, showcases their structure-property-performance relationships. The recent breakthroughs in device performance and emerging strategies, such as heterostructure modulation and defect engineering, have been reviewed and summarized. Furthermore, existing critical challenges, which specifically include material stability, scalability, and charge recombination, as well as proposed future directions involving material discovery, smart PEC systems, and integrated solar-battery schemes, have been overviewed, and their perspectives have been discussed. This comprehensive review aims to provide insights that accelerate the development of next-generation PEC technologies enabled by 2D materials for advanced and smart photo-assisted batteries.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"56 ","pages":"Article 101012"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147400104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the effects of heteroatom (Cl, S, N) doping on chronoamperometrically synthesized graphene oxides and their interaction with glyme-based electrolytes in sodium-ion batteries","authors":"MohammedMustafa Almarzoge ,&nbsp;Metin Gencten ,&nbsp;Gamzenur Özsin","doi":"10.1016/j.flatc.2026.100998","DOIUrl":"10.1016/j.flatc.2026.100998","url":null,"abstract":"<div><div>Na-ion batteries (SIBs) are promising energy storage devices, with graphene derivatives emerging as new anode materials. Chronoamperometry enables precise, mild synthesis of high-quality graphene oxide. Here, chlorine-, sulfur-, and nitrogen-doped graphene oxides (ClGO, SGO, NGO) are fabricated via a simple, straightforward, cost-effective, and ambient-condition method that does not require an inert atmosphere chronoamperometric method and tested as SIB anodes in an ether-based electrolyte. The utilization of diglyme as an electrolyte solvent improved the overall capacity and cycle life of DGO anodes, as diglyme is considered a co-intercalating electrolyte that contributes to the storage of Na⁺. Morphological analyses reveal that all powders exhibit a two-dimensional structure with uniformly dispersed dopant atoms. The single DGO electrodes show initial discharge capacities of ∼415, 733, and 952 mAh g⁻¹ at 0.1C for ClGO, SGO, and NGO, respectively. Electrochemical tests demonstrate that ClGO, SGO, and NGO electrodes deliver reversible capacities of ∼78, 199, and 240 mAh g⁻¹ after 500 cycles at 2C (200 mA g⁻¹). After 100 cycles at 5C (1000 mA g⁻¹), they retain ∼90, 96, and 78 mAh g⁻¹, showing high stability. At 10C, reversible capacities of ∼125, 210, and 260 mAh g⁻¹ are sustained after 50 cycles. All DGO samples exhibit a mixed charge storage mechanism, primarily governed by capacitive control, with a minor contribution from diffusion-controlled processes, signifying rapid charge transfer and effective ion storage characteristics. These results highlight a simple chronoamperometric route to produce DGO anodes with excellent stability and capacity, providing a promising pathway for large-scale SIBs applications.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"56 ","pages":"Article 100998"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Imine-modified nitrogen-doped graphene quantum dots and metal nanocomposites: Synthesis, characterization, DFT studies, plasmon-assisted nonlinear absorption, and broadband optical limiting properties","authors":"Anıl Doğan ,&nbsp;Elif Akhüseyin Yıldız ,&nbsp;Huseyin Unver ,&nbsp;Bahadir Boyacioglu ,&nbsp;Mustafa Yıldız ,&nbsp;Ayhan Elmali ,&nbsp;Ahmet Karatay","doi":"10.1016/j.flatc.2026.101016","DOIUrl":"10.1016/j.flatc.2026.101016","url":null,"abstract":"<div><div>Polyethyleneimine (PEI)-functionalized nitrogen (N)-doped graphene quantum dots (PEI N-GQDs), their Schiff base-modified imine derivatives (Schiff-PEI N-GQDs), and related metal nanoparticle (Ag, Mn, Co) nanocomposites were synthesized to investigate their broadband nonlinear optical (NLO) and optical limiting (OL) properties. Imine functionalization and metal integration significantly modulate the excited-state dynamics and charge transfer properties of GQDs. While CoNPs/PEI N-GQDs and MnNPs/PEI N-GQDs systems exhibit photoluminescence profiles similar to those of pure PEI N-GQDs, AgNPs bound to 4,6-dimethoxysalicylaldehyde-modified PEI N-GQDs exhibit pronounced fluorescence quenching due to strong intramolecular charge transfer (ICT). This mechanism has been confirmed by ultrafast transient absorption spectroscopy. The analysis of femto- and pico-second <em>Z</em>-scan measurements has revealed a range of distinct nonlinear absorption (NA) mechanisms, with the variation in these mechanisms occurring in accordance with the wavelength, extending from the ultraviolet to the near-infrared region (400–1200 nm). AgNPs/4,6-DIMETSAL-PEI N-GQDs exhibit superior NA behavior attributed to plasmonic field enhancement and the lowest OL thresholds at 400 nm; MnNPs/PEI N-GQDs exhibit dominant NA in the near-infrared region due to defect-state-supported multi-photon absorption processes. Density functional theory (DFT) calculations reveal increased polarizability, high dipole moment, and electronic stability in the AgNP-based Schiff base system, supporting the experimentally observed strong NA behavior. These results provide a clear structure-property-mechanism relationship for the design of GQD-based nanocomposites with wavelength-selective OL performance.</div></div>","PeriodicalId":316,"journal":{"name":"FlatChem","volume":"56 ","pages":"Article 101016"},"PeriodicalIF":6.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}