Engineering the Interfacing of Molecules with 2D Transition Metal Dichalcogenides: Enhanced Multifunctional Electronics.

ConspectusEngineering all interfaces between different components in electronic devices is the key to control and optimize fundamental physical processes such as charge injection at metal-semiconductor interfaces, gate modulation at the dielectric-semiconductor interface, and carrier modulation at semiconductor-environment interfaces. The use of two-dimensional (2D) crystals as semiconductors, by virtue of their atomically flat dangling bond-free structures, can facilitate the tailoring of such interfaces effectively. In this context, 2D transition metal dichalcogenides (TMDs) have garnered tremendous attention over the past two decades owing to their exclusive and outstanding physical and chemical characteristics such as their strong light-matter interactions and high charge mobility. These properties position them as promising building blocks for next-generation semiconductor materials. The combination of their large specific surface area, unique electronic structure, and properties highly sensitive to environmental changes makes 2D TMDs appealing platforms for applications in optoelectronics and sensing. While a broad arsenal of TMDs has been made available that exhibit a variety of electronic properties, the latter are unfortunately hardly tunable. To overcome this problem, the controlled functionalization of TMDs with molecules and assemblies thereof represents a most powerful strategy to finely tune their surface characteristics for electronics. Such functionalization can be used not only to encapsulate the electronic material, therefore enhancing its stability in air, but also to impart dynamic, stimuli-responsive characteristics to TMDs and to selectively recognize the presence of a given analyte in the environment, demonstrating unprecedented application potential.In this Account, we highlight the most enlightening recent progress made on the interface engineering in 2D TMD-based electronic devices via covalent and noncovalent functionalization with suitably designed molecules, underlining the remarkable synergies achieved. While electrode functionalization allows modulating charge injection and extraction, the functionalization of the dielectric substrate enables tuning of the carrier concentration in the device channel, and the functionalization of the upper surface of 2D TMDs allows screening the interaction with the environment and imparts molecular functionality to the devices, making them versatile for various applications. The tailored interfaces enable enhanced device performance and open up avenues for practical applications. This Account specifically focuses on our recent endeavor in the unusual properties conferred to 2D TMDs through the functionalization of their interfaces with stimuli-responsive molecules or molecular assemblies. This includes electrode-functionalized devices with modulable performance and charge carriers, molecular-bridged TMD network devices with overall enhanced electrical properties, sensor devices that are highly responsive to changes in the external environment, in particular, electrochemically switchable transistors that react to external electrochemical signals, optically switchable transistors that are sensitive to external light inputs, and multiresponsive transistors that simultaneously respond to multiple external stimuli including optical, electrical, redox, thermal, and magnetic inputs and their application in the development of unprecedented memories, artificial synapses, and logic inverters. By presenting the current challenges, opportunities, and prospects in this blooming research field, we will discuss the powerful integration of such strategies for next-generation electronic digital devices and logic circuitries, outlining future directions and potential breakthroughs in interface engineering.

Tailoring electrochemically exfoliated graphene electroactive pathways in cementitious composites for structural health monitoring of constructions.

Manipulating and exerting a nanoscale control over the structure of multicomponent materials represents a powerful strategy for tailoring multifunctional composites for structural health monitoring applications. The use of self-sensing, electroactive cementitious composites in large-scale applications is severely hindered by the absence of clear directives and a thorough understanding of the electrical conduction mechanisms taking place within the cement matrix. Here we report on a nanoscale approach towards this goal which is accomplished via the development of a novel, multifunctional cementitious composite incorporating electrochemically exfoliated graphene (EEG). The use of commercially available poly(carboxylate ether)-based superplasticizer allowed us to embed in the cement mortar up to 0.8 wt% of EEG which is fully dispersed in the matrix. The multiscale investigation made it possible to assess the effect of such high dosages of EEG on the mechanical performance and hydration degree of cementitious composites. We used electrochemical impedance spectroscopy to monitor the formation of electroactive EEG-based percolation paths for charge transfer within cement mortar, the latter displaying resistivities of 2.67 kΩ cm as well as EEG-cement-EEG capacitive paths with capacitance of 2.20 × 10-10 F cm-1 for composites incorporating 0.6 wt% of EEG. Noteworthy, we have proposed here for the first time an electrical equivalent circuit for the impedance spectroscopy analysis of cementitious composites with high loadings of graphene, exceeding the percolation threshold. These findings underscore the potential of nanoscale structures for civil engineering applications and more specifically may open new avenues for the technological application of graphene-based cementitious composites in self-sensing structures.

Template-assisted synthesis of hollow anthraquinone-based covalent organic frameworks for aqueous zinc-ion hybrid supercapacitors.

Anthraquinone-based hollow COFs were synthesized via a template-assisted method involving polystyrene nanospheres as the hard template, which enabled doubling the specific capacitance and energy density compared to non-templated COFs. Our approach can be extended to other COFs, offering a promising strategy for enhancing the performance of COF-based electrodes in energy storage applications.

Tunable Emissive CsPbBr3/Cs4PbBr6 Quantum Dots Engineered by Discrete Phase Transformation for Enhanced Photogating in Field-Effect Phototransistors.

Precise control of quantum structures in hybrid nanocrystals requires advancements in scientific methodologies. Here, on the design of tunable CsPbBr3/Cs4PbBr6 quantum dots are reported by developing a unique discrete phase transformation approach in Cs4PbBr6 nanocrystals. Unlike conventional hybrid systems that emit solely in the green region, this current strategy produces adjustable luminescence in the blue (450 nm), cyan (480 nm), and green (510 nm) regions with high photoluminescence quantum yields up to 45%, 60%, and 85%, respectively. Concentration-dependent studies reveal that phase transformation mechanisms and the factors that drive CsBr removal occur at lower dilutions while the dissolution-recrystallization process dominates at higher dilutions. When the polymer-CsPbBr3/Cs4PbBr6 integrated into a field-effected transistor the resulting phototransistors featured enhanced photosensitivity exceeding 105, being the highest reported for an n-type phototransistor, while maintaining good transistor performances as compared to devices consisting of polymer-CsPbBr3 NCs.

Defect Engineering of MoTe2 via Thiol Treatment for Type III van der Waals Heterojunction Phototransistor.

Molybdenum ditelluride (MoTe2) nanosheets have displayed intriguing physicochemical properties and opto-electric characteristics as a result of their tunable and small band gap (Eg ∼ 1 eV), facilitating concurrent electron and hole transport. Despite the numerous efforts devoted to the development of p-type MoTe2 field-effect transistors (FETs), the presence of tellurium (Te) point vacancies has caused serious reliability issues. Here, we overcome this major limitation by treating the MoTe2 surface with thiolated molecules to heal Te vacancies. Comprehensive materials and electrical characterizations provided unambiguous evidence for the efficient chemisorption of butanethiol. Our thiol-treated MoTe2 FET exhibited a 10-fold increase in hole current and a positive threshold voltage shift of 25 V, indicative of efficient hole carrier doping. We demonstrated that our powerful molecular engineering strategy can be extended to the controlled formation of van der Waals heterostructures by developing an n-SnS2/thiol-MoTe2 junction FET (thiol-JFET). Notably, the thiol-JFET exhibited a significant negative photoresponse with a responsivity of 50 A W-1 and a fast response time of 80 ms based on band-to-band tunneling. More interestingly, the thiol-JFET displayed a gate tunable trimodal photodetection comprising two photoactive modes (positive and negative photoresponse) and one photoinactive mode. These findings underscore the potential of molecular engineering approaches in enhancing the performance and functionality of MoTe2-based nanodevices as key components in advanced 2D-based optoelectronics.

Rational Construction of Two-Dimensional Conjugated Metal-Organic Frameworks (2D c-MOFs) for Electronics and Beyond.

ConspectusTwo-dimensional conjugated metal-organic frameworks (2D c-MOFs) have emerged as a novel class of multifunctional materials, attracting increasing attention due to their highly customizable chemistry yielding programmable and unprecedented structures and properties. In particular, over the past decade, the synergistic relationship between the conductivity and porosity of 2D c-MOFs has paved the way toward their widespread applications. Despite their promising potential, the majority of 2D c-MOFs have yet to achieve atomically precise crystal structures, hindering the full understanding and control over their electronic structure and intrinsic charge transport characteristics. When modulating the charge transport properties of two-dimensional layered framework materials, decoupling the charge transport processes within and in between layers is of paramount importance, yet it represents a significant challenge. Unfortunately, 2D c-MOFs systems developed so far have failed to address such a major research target, which can be achieved solely by manipulating charge transport properties in 2D c-MOFs. 2D c-MOFs offer a significant advantage over organic radical molecules and covalent organic frameworks: polymerization through oxidative coordination is a viable route to form "spin-concentrated assemblies". However, the role of these spin centers in charge transport processes is still poorly understood, and the intrinsic dynamics and properties of these spins have seldom been investigated. Consequently, overcoming these challenges is essential to unlock the full potential of 2D c-MOFs in electronics and other related fields, as a new type of quantum materials.In this Account, we summarize and discuss our group's efforts to achieve full control at the atomic level over the structure of 2D c-MOFs and their applications in electronics and spintronics, thereby providing distinct evidence on 2D c-MOFs as a promising platform for exploring novel quantum phenomena. First, we unravel the key role played by the rational design of the ligands to decrease the boundary defects, achieve atomically precise large single crystals, and investigate the intrinsic charge transport properties of 2D c-MOFs. The advantages and disadvantages of the current structural elucidation strategies will be discussed. Second, the fundamental challenge in 2D c-MOF charge transport studies is to decouple the in-plane and interlayer charge transport pathways and achieve precise tuning of the charge transport properties in 2D c-MOFs. To address this challenge, we propose a design concept for the second-generation conjugated ligands, termed "programmable conjugated ligands", to replace the current first-generation ligands which lack modifiability as they mainly consist of sp2 hybridization atoms. Our efforts also extend to controlling the spin dynamics properties of 2D c-MOFs as "spin concentrated assemblies" using a bottom-up strategy.We hope this Account provides enlightening fundamental insights and practical strategies to overcome the major challenges of 2D c-MOFs for electronics and spintronics. Through the rational design of structural modulation within the 2D plane and interlayer interactions, we are committed to making significant steps forward for boosting the functional complexity of this blooming family of materials, thereby opening clear perspectives toward their practical application in electronics with the ultimate goal of inspiring further development of 2D c-MOFs and unleashing their full potential as an emerging quantum material.

State of Play of Critical Mineral-Based Catalysts for Electrochemical E-Refinery to Synthetic Fuels.

The pursuit of decarbonization involves leveraging waste CO2 for the production of valuable fuels and chemicals (e.g., ethanol, ethylene, and urea) through the electrochemical CO2 reduction reactions (CO2RR). The efficacy of this process heavily depends on electrocatalyst performance, which is generally reliant on high loading of critical minerals. However, the supply of these minerals is susceptible to shortage and disruption, prompting concerns regarding their usage, particularly in electrocatalysis, requiring swift innovations to mitigate the supply risks. The reliance on critical minerals in catalyst fabrication can be reduced by implementing design strategies that improve the available active sites, thereby increasing the mass activity. This review seeks to discuss and analyze potential strategies, challenges, and opportunities for improving catalyst activity in CO2RR with a special attention to addressing the risks associated with critical mineral scarcity. By shedding light onto these aspects of critical mineral-based catalyst systems, this review aims to inspire the development of high-performance catalysts and facilitates the practical application of CO2RR technology, whilst mitigating adverse economic, environmental, and community impacts.

Li Promoting Long Afterglow Organic Light-Emitting Transistor for Memory Optocoupler Module.

The artificial brain is conceived as advanced intelligence technology, capable to emulate in-memory processes occurring in the human brain by integrating synaptic devices. Within this context, improving the functionality of synaptic transistors to increase information processing density in neuromorphic chips is a major challenge in this field. In this article, Li-ion migration promoting long afterglow organic light-emitting transistors, which display exceptional postsynaptic brightness of 7000 cd m-2 under low operational voltages of 10 V is presented. The postsynaptic current of 0.1 mA operating as a built-in threshold switch is implemented as a firing point in these devices. The setting-condition-triggered long afterglow is employed to drive the photoisomerization process of photochromic molecules that mimic neurotransmitter transfer in the human brain for realizing a key memory rule, that is, the transition from long-term memory to permanent memory. The combination of setting-condition-triggered long afterglow with photodiode amplifiers is also processed to emulate the human responding action after the setting-training process. Overall, the successful integration in neuromorphic computing comprising stimulus judgment, photon emission, transition, and encoding,  to emulate the complicated decision tree of the human brain is demonstrated.

Boosting Zinc Hybrid Supercapacitor Performance via Thiol Functionalization of Graphene-Based Cathodes.

Zinc hybrid supercapacitors (Zn-HSCs) hold immense potential toward the next-generation energy storage systems, effectively spanning the divide between conventional lithium-ion batteries (LIBs) and supercapacitors. Unfortunately, the energy density of most of Zn-HSCs has not yet rivalled the levels observed in LIBs. The electrochemical performance of aqueous Zn-HSCs can be enhanced through the chemical functionalization of graphene-based cathode materials with thiol moieties as they will be highly suitable for favoring Zn2+ adsorption/desorption. Here, a single-step reaction is employed to synthesize thiol-functionalized reduced graphene oxide (rGOSH), incorporating both oxygen functional groups (OFGs) and thiol functionalities, as demonstrated by X-ray photoelectron spectroscopy (XPS) studies. Electrochemical analysis reveals that rGOSH cathodes exhibit a specific capacitance (540 F g-1) and specific capacity (139 mAh g-1) at 0.1 A g-1 as well as long-term stability, with over 92% capacitance retention after 10 000 cycles, outperforming chemically reduced graphene oxide (CrGO). Notably, rGOSH electrodes displayed an exceptional maximum energy density of 187.6 Wh kg-1 and power density of 48.6 kW kg-1. Overall, this study offers an unprecedented powerful strategy for the design and optimization of cathode materials, paving the way for efficient and sustainable energy storage solutions to meet the increasing demands of modern energy applications.

2D Conjugated Polymer Thin Films for Organic Electronics: Opportunities and Challenges.

2D conjugated polymers (2DCPs) possess extended in-plane π-conjugated lattice and out-of-plane π-π stacking, which results in enhanced electronic performance and potentially unique band structures. These properties, along with predesignability, well-defined channels, easy postmodification, and order structure attract extensive attention from material science to organic electronics. In this review, the recent advance in the interfacial synthesis and conductivity tuning strategies of 2DCP thin films, as well as their application in organic electronics is summarized. Furthermore, it is shown that, by combining topology structure design and targeted conductivity adjustment, researchers have fabricated 2DCP thin films with predesigned active groups, highly ordered structures, and enhanced conductivity. These films exhibit great potential for various thin-film organic electronics, such as organic transistors, memristors, electrochromism, chemiresistors, and photodetectors. Finally, the future research directions and perspectives of 2DCPs are discussed in terms of the interfacial synthetic design and structure engineering for the fabrication of fully conjugated 2DCP thin films, as well as the functional manipulation of conductivity to advance their applications in future organic electronics.

Exceptionally High Perfluorooctanoic Acid Uptake in Water by a Zirconium-Based Metal-Organic Framework through Synergistic Chemical and Physical Adsorption.

Perfluorooctanoic acid (PFOA) is an environmental contaminant ubiquitous in water resources, which as a xenobiotic and carcinogenic agent, severely endangers human health. The development of techniques for its efficient removal is therefore highly sought after. Herein, we demonstrate an unprecedented zirconium-based MOF (PCN-999) possessing Zr6 and biformate-bridged (Zr6)2 clusters simultaneously, which exhibits an exceptional PFOA uptake of 1089 mg/g (2.63 mmol/g), representing a ca. 50% increase over the previous record for MOFs. Single-crystal X-ray diffraction studies and computational analysis revealed that the (Zr6)2 clusters offer additional open coordination sites for hosting PFOA. The coordinated PFOAs further enhance the interaction between coordinated and free PFOAs for physical adsorption, boosting the adsorption capacity to an unparalleled high standard. Our findings represent a major step forward in the fundamental understanding of the MOF-based PFOA removal mechanism, paving the way toward the rational design of next-generation adsorbents for per- and polyfluoroalkyl substance (PFAS) removal.

Molecular Connectors Boosting the Performance of MoS2 Cathodes in Zinc-Ion Batteries.

Zinc-ion batteries (ZIBs) are promising energy storage systems due to high energy density, low-cost, and abundant availability of zinc as a raw material. However, the greatest challenge in ZIBs research is lack of suitable cathode materials that can reversibly intercalate Zn2+ ions. 2D layered materials, especially MoS2-based, attract tremendous interest due to large surface area and ability to intercalate/deintercalate ions. Unfortunately, pristine MoS2 obtained by traditional protocols such as chemical exfoliation or hydrothermal/solvothermal methods exhibits limited electronic conductivity and poor chemical stability upon charge/discharge cycling. Here, a novel molecular strategy to boost the electrochemical performance of MoS2 cathode materials for aqueous ZIBs is reported. The use of dithiolated conjugated molecular pillars, that is, 4,4'-biphenyldithiols, enables to heal defects and crosslink the MoS2 nanosheets, yielding covalently bridged networks (MoS2-SH2) with improved ionic and electronic conductivity and electrochemical performance. In particular, MoS2-SH2 electrodes display high specific capacity of 271.3 mAh g-1 at 0.1 A g-1, high energy density of 279 Wh kg-1, and high power density of 12.3 kW kg-1. With its outstanding rate capability (capacity of 148.1 mAh g-1 at 10 A g-1) and stability (capacity of 179 mAh g-1 after 1000 cycles), MoS2-SH2 electrodes outperform other MoS2-based electrodes in ZIBs.

"Clickable" graphene nanoribbons for biosensor interfaces.

We report on the synthesis of "clickable" graphene nanoribbons (GNRs) and their application as a versatile interface for electrochemical biosensors. GNRs are successfully deposited on gold-coated working electrodes and serve as a platform for the covalent anchoring of a bioreceptor (i.e., a DNA aptamer), enabling selective and sensitive detection of Interleukin 6 (IL6). Moreover, when applied as the intermediate linker on reduced graphene oxide (rGO)-based field-effect transistors (FETs), the GNRs provide improved robustness compared to conventional aromatic bi-functional linker molecules. GNRs enable an orthogonal and covalent attachment of a recognition unit with a considerably higher probe density than previously established methods. Interestingly, we demonstrate that GNRs introduce photoluminescence (PL) when applied to rGO-based FETs, paving the way toward the simultaneous optical and electronic probing of the attached biointerface.

Tunable Charge Transport and Spin Dynamics in Two-Dimensional Conjugated Metal-Organic Frameworks.

Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have attracted increasing interest in electronics due to their (semi)conducting properties. Charge-neutral 2D c-MOFs also possess persistent organic radicals that can be viewed as spin-concentrated arrays, affording new opportunities for spintronics. However, the strong π-interaction between neighboring layers of layer-stacked 2D c-MOFs annihilates active spin centers and significantly accelerates spin relaxation, severely limiting their potential as spin qubits. Herein, we report the precise tuning of the charge transport and spin dynamics in 2D c-MOFs via the control of interlayer stacking. The introduction of bulky side groups on the conjugated ligands enables a significant dislocation of the 2D c-MOFs layers from serrated stacking to staggered stacking, thereby spatially weakening the interlayer interactions. As a consequence, the electrical conductivity of 2D c-MOFs decreases by 6 orders of magnitude, while the spin density achieves more than a 30-fold increase and the spin-lattice relaxation time (T1) is increased up to ∼60 µs, hence being superior to the reference 2D c-MOFs with compact stackings whose spin relaxation is too fast to be detected. Spin dynamics results also reveal that spinless polaron pairs or bipolarons play critical roles in the charge transport of these 2D c-MOFs. Our strategy provides a bottom-up approach for enlarging spin dynamics in 2D c-MOFs, opening up pathways for developing MOF-based spintronics.

Humidity Sensing with Supramolecular Nanostructures.

Precise monitoring of the humidity level is important for the living comfort and for many applications in various industrial sectors. Humidity sensors have thus become one among the most extensively studied and used chemical sensors by targeting a maximal device performance through the optimization of the components and working mechanism. Among different moisture-sensitive systems, supramolecular nanostructures are ideal active materials for the next generation of highly efficient humidity sensors. Their noncovalent nature guarantees fast response, high reversibility, and fast recovery time in the sensing event. Herein, the most enlightening recent strategies on the use of supramolecular nanostructures for humidity sensing are showcased. The key performance indicators in humidity sensing, including operation range, sensitivity, selectivity, response, and recovery speed are discussed as milestones for true practical applications. Some of the most remarkable examples of supramolecular-based humidity sensors are presented, by describing the finest sensing materials, the operating principles, and sensing mechanisms, the latter being based on the structural or charge-transport changes triggered by the interaction of the supramolecular nanostructures with the ambient humidity. Finally, the future directions, challenges, and opportunities for the development of humidity sensors with performance beyond the state of the art are discussed.

MOF (UiO-66-NH2)@COF (TFP-TABQ) hybrids via on-surface condensation reactions for sustainable energy storage.

Core-shell MOF@COF hybrids were synthesized via subsequent modification of MOF UiO-66-NH2 with 1,3,5-triformylphloroglucinol (TFP) and 2,3,5,6-tetraaminobenzoquinone (TABQ). The hybrids exhibited significant surface area (236 m2 g-1) and outstanding electrochemical performance (103 F g-1 at 0.5 A g-1), surpassing both COFs and MOFs, thereby showcasing the potential of on-surface condensation reactions for developing high-performance energy storage devices.

Mechanical Properties of Conducting Printed Nanosheet Network Thin Films Under Uniaxial Compression.

Thin film networks of solution processed nanosheets show remarkable promise for use in a broad range of applications including strain sensors, energy storage, printed devices, textile electronics, and more. While it is known that their electronic properties rely heavily on their morphology, little is known of their mechanical nature, a glaring omission given the effect mechanical deformation has on the morphology of porous systems and the promise of mechanical post processing for tailored properties. Here, this work employs a recent advance in thin film mechanical testing called the Layer Compression Test to perform the first in situ analysis of printed nanosheet network compression. Due to the well-defined deformation geometry of this unique test, this work is able to explore the out-of-plane elastic, plastic, and creep deformation in these systems, extracting properties of elastic modulus, plastic yield, viscoelasticity, tensile failure and sheet bending vs. slippage under both out of plane uniaxial compression and tension. This work characterizes these for a range of networks of differing porosities and sheet sizes, for low and high compression, as well as the effect of chemical cross linking. This work explores graphene and MoS2 networks, from which the results can be extended to printed nanosheet networks as a whole.

Opto-Electrochemical Synaptic Memory in Supramolecularly Engineered Janus 2D MoS2.

Artificial synapses combining multiple yet independent signal processing strategies in a single device are key enabler to achieve high-density of integration, energy efficiency, and fast data manipulation in brain-like computing. By taming functional complexity, the use of hybrids comprising multiple materials as active components in synaptic devices represents a powerful route to encode both short-term potentiation (STP) and long-term potentiation (LTP) in synaptic circuitries. To meet such a grand challenge, herein a novel Janus 2D material is developed by dressing asymmetrically the two surfaces of 2D molybdenum disulfide (MoS2 ) with an electrochemically-switchable ferrocene (Fc)/ ferrocenium (Fc+ ) redox couple and an optically-responsive photochromic azobenzene (Azo). Upon varying the magnitude of the electrochemical stimulus, it is possible to steer the transition between STP and LTP, thereby either triggering electrochemical doping of Fc/Fc+  pair on MoS2  or controlling an adsorption/desorption process of such redox species on MoS2 . In addition, a lower magnitude LTP is recorded by activating the photoisomerization of azobenzene chemisorbed molecules and therefore modulating the dipole-induced doping of the 2D semiconductor. Significantly, the interplay of electrochemical and optical stimuli makes it possible to construct artificial synapses where LTP can be boosted to 4-bit (16 memory states) while simultaneously functioning as STP.

Enhancing the Carrier Transport in Monolayer MoS2 through Interlayer Coupling with 2D Covalent Organic Frameworks.

The coupling of different 2D materials (2DMs) to form van der Waals heterostructures (vdWHs) is a powerful strategy for adjusting the electronic properties of 2D semiconductors, for applications in opto-electronics and quantum computing. 2D molybdenum disulfide (MoS2 ) represents an archetypical semiconducting, monolayer thick versatile platform for the generation of hybrid vdWH with tunable charge transport characteristics through its interfacing with molecules and assemblies thereof. However, the physisorption of (macro)molecules on 2D MoS2 yields hybrids possessing a limited thermal stability, thereby jeopardizing their technological applications. Herein, the rational design and optimized synthesis of 2D covalent organic frameworks (2D-COFs) for the generation of MoS2 /2D-COF vdWHs exhibiting strong interlayer coupling effects are reported. The high crystallinity of the 2D-COF films makes it possible to engineer an ultrastable periodic doping effect on MoS2 , boosting devices' field-effect mobility at room temperature. Such a performance increase can be attributed to the synergistic effect of the efficient interfacial electron transfer process and the pronounced suppression of MoS2 's lattice vibration. This proof-of-concept work validates an unprecedented approach for the efficient modulation of the electronic properties of 2D transition metal dichalcogenides toward high-performance (opto)electronics for CMOS digital circuits.

Harnessing Small-Molecule Analyte Detection in Complex Media: Combining Molecularly Imprinted Polymers, Electrolytic Transistors, and Machine Learning.

Small-molecule analyte detection is key for improving quality of life, particularly in health monitoring through the early detection of diseases. However, detecting specific markers in complex multicomponent media using devices compatible with point-of-care (PoC) technologies is still a major challenge. Here, we introduce a novel approach that combines molecularly imprinted polymers (MIPs), electrolyte-gated transistors (EGTs) based on 2D materials, and machine learning (ML) to detect hippuric acid (HA) in artificial urine, being a critical marker for toluene intoxication, parasitic infections, and kidney and bowel inflammation. Reduced graphene oxide (rGO) was used as the sensory material and molecularly imprinted polymer (MIP) as supramolecular receptors. Employing supervised ML techniques based on symbolic regression and compressive sensing enabled us to comprehensively analyze the EGT transfer curves, eliminating the need for arbitrary signal selection and allowing a multivariate analysis during HA detection. The resulting device displayed simultaneously low operating voltages (<0.5 V), rapid response times (≤10 s), operation across a wide range of HA concentrations (from 0.05 to 200 nmol L-1), and a low limit of detection (LoD) of 39 pmol L-1. Thanks to the ML multivariate analysis, we achieved a 2.5-fold increase in the device sensitivity (1.007 µA/nmol L-1) with respect to the human data analysis (0.388 µA/nmol L-1). Our method represents a major advance in PoC technologies, by enabling the accurate determination of small-molecule markers in complex media via the combination of ML analysis, supramolecular analyte recognition, and electrolytic transistors.