Decrease In Work Function Research Articles

Synergistic Coordination Effect and Metal-Support Interaction Engineering of Single-Atom Mn-N2 Sites for Boosting Sensitive and Selective Dopamine Biosensing in Human Serum.

Coordination environment of metal atoms is core for designing high-performance single-atom catalysts (SACs), while metal-support interaction also has an important effect on structure-function relationship. Nevertheless, the interaction effect of metal-support is mostly ignored. Through synergistic regulation of coordination environment and metal-support interaction, Mn SAC with atom-dispersed Mn-N2 sites on dopamine (DA) support is synthesized for sensitive and selective DA oxidation based on theoretical calculations and experimental explorations. MnN2 presents the more optimal catalytic site for DA oxidation than other coordination conditions, enhancing sensitivity including a wide range, a low limit of detection, and particularly a very low catalytic potential. The construction of Mn-N2 active sites on DA carbon promotes the coupling between Mn metal atoms and DA support, decreasing work function, facilitating electron exchange, shortening response time, and boosting selectivity. Both the catalytic mechanism of Mn SAC toward DA and the relation construction of catalyst's structure and catalytic function are established.

A DFT study on antimonene as a drug delivery vehicle for carmustine, lomustine and nitrosourea anticancer drugs

We used antimonene (Sb) as a delivery vehicle for transporting drugs like Carmustine (CMT), Lomustine (LOMU) and Nitrosourea (NU) in both gaseous and liquid states. The Sb nanosheet structure is stable, and its potential for drug adsorption has been investigated in both parallel and perpendicular directions. The parallel configuration is most stable with a higher adsorption energy of −1.18 eV, −0.63 eV and −1.14 eV for LOMU, CMT and NU respectively. We investigated structural parameters, electronic properties, work function and chemical reactivity. Only NU alters the Sb’s semiconductor behaviour to metallic and has the shortest recovery time in the parallel direction. Hirshfield charge analysis revealed that nanosheet displays electron accepting properties, whereas drugs act as electron donors. The decreased work function for CMT and LOMU enhances substrate activity, indicating stronger interactions that may improve drug delivery. We confirmed the drug’s effective interaction with amino acids without impairing proteins. Furthermore, calculated results predicted a minimal acidic environment of malignant growth, CM, NU and LOMU drugs could start to release from the Sb surface without significantly altering the structural properties. This study illustrates how Sb nanosheet holds promise as an effective carrier for drug delivery in biomedical applications.

Green and solid state reduction of GO monolayers sandwiched between Arachidic acid LB layers

A novel, single step and environment friendly solid state approach for reduction of graphene oxide (GO) monolayers has been demonstrated, in which, arachidic acid/GO/arachidic acid (AA/GO/AA) sandwich structure obtained by Langmuir-Blodgett (LB) technique was heat treated at moderate temperatures to obtain RGO sheets. Heat treatment of AA/GO/AA sandwich structure at 200 °C results in substantial reduction of GO, with concurrent removal of AA molecules. Such developed RGO sheets possess sp2-C content of ∼69 %, O/C ratio of ∼0.17 and significantly reduced I(D)/I(G) ratio of ∼1.1. Ultraviolet photoelectron spectroscopy (UPS) studies on RGO sheets evidenced significant increase in density of states in immediate vicinity of Fermi level and decrease in work function after reduction. Bottom gated field effect transistors fabricated with isolated RGO sheets displayed charge neutrality point at a positive gate voltage, indicating p-type nature, consistent with UPS and electrostatic force microscopy (EFM) measurement results. The RGO sheets obtained by heat treatment of AA/GO/AA sandwich structure exhibited conductivity in the range of 2–7 S/cm and field effect mobility of 0.03–2 cm2/Vs, which are comparable with values reported for RGO sheets obtained by various chemical/thermal reduction procedures. The extent of GO reduction is determined primarily by proximity of AA molecules and found to be unaltered with either escalation of heat treatment temperature or increase of AA content in sandwich structure. The single-step GO reduction approach demonstrated in this work is an effective way for development of RGO monolayers with high structural quality towards graphene-based electronic device applications.

Spatial and Bidirectional Work Function Modulation of Monolayer Graphene with Patterned Polymer "Fluorozwitterists".

Understanding the electronic properties resulting from soft-hard material interfacial contact has elevated the utility of functional polymers in advanced materials and nanoscale structures, such as in work function engineering of two-dimensional (2D) materials to produce new types of high-performance devices. In this paper, we describe the electronic impact of functional polymers, containing both zwitterionic and fluorocarbon components in their side chains, on the work function of monolayer graphene through the preparation of negative-tone photoresists, which we term "fluorozwitterists." The zwitterionic and fluorinated groups each represent dipole-containing moieties capable of producing distinct surface energies as thin films. Kelvin probe force microscopy revealed these polymers to have a p-doping effect on graphene, which contrasts the work function decrease typically associated with polymer-to-graphene contact. Copolymerization of fluorinated zwitterionic monomers with methyl methacrylate and a benzophenone-substituted methacrylate produced copolymers that were amenable to photolithographic fabrication of fluorozwitterist structures. Consequently, spatial alteration of zwitterion coverage across graphene yielded stripes that resemble a lateral p-i-n diode configuration, with local increase or decrease of work function. Overall, this polymeric fluorozwitterist design is suitable for enabling simple, solution-based surface patterning and is anticipated to be useful for spatial work function modulation of 2D materials integrated into electronic devices.

Metal atom doping with GeC: Tuning electronic, magnetic and electrocatalytic hydrogen evolution

The crystal structure stability, electronic and magnetic properties, field emission, and catalytic properties of the metal-doped GeC systems are investigated by the first principles. The Ef (formation energy) in the range of −5.713 to −14.240 eV indicates that the metal-doped GeC systems have energy stability. The Al-, Cr-, Fe-, Co-, Cu-, and Zn-doped GeC systems exhibit metallic properties, but the Ti-, V-, Mn-, and Ni-doped GeC systems retain semiconductor properties. Notably, the V-, Cr-, Mn-, Fe-, Co-, Cu-, and Zn-doped GeC systems exhibit magnetism due to doping effects. In addition, the Ti-, V-, Cr-, Mn-, Fe-, and Co-doped GeC systems have field emission properties relative to the intrinsic GeC due to the decrease of work function. Importantly, the low over-potential indicates that the doping systems have strong electro-catalytic hydrogen production ability. Therefore, the metal-doped GeC has potential applications in spintronic, field emission devices, and electro-catalytic hydrogen production.

Unravelling the Ageing Effects of PDMS‐Based Triboelectric Nanogenerators

AbstractAgeing of elastomeric materials in triboelectric nanogenerators (TENGs) often leads to compromised electrical performance and can greatly affect their real‐world application as next‐generation energy harvesters and self‐powered sensors. Herein, the ageing behavior of PDMS‐based TENGs is investigated by probing the dielectric and mechanical properties of the membrane materials. Over time, ageing of PDMS after 17 months is evinced by a decline by 71%, 68% and 52% in open‐circuit voltage, short‐circuit current and charge transfer, respectively, and an increase by 6.8 times in surface charge decay rate. The reduced electrical performance can be attributed to a decrease in work function, dielectric constant, surface adhesion and heterogeneity in stiffness, as well as an increase in loss tangent. The effect of chemical chain scission on the PDMS surface is confirmed through nearfield infrared nanospectroscopy. This study gives insights into the underlying mechanism behind the ageing of PDMS‐based TENGs, paving the way to future work for ameliorating these ageing‐related issues with the aim to ensure long‐term stability of practical triboelectric devices.

Synthesis of conducting polymer intercalated sodium vanadate nanofiber composites as active materials for aqueous zinc-ion batteries and NH3 gas sensors at room temperature

Among the key technologies required for building industrial safety systems is portable integrated safety devices based on gas sensors and rechargeable batteries. In preparation for such integrated devices, this study focuses on the synthesis of sodium vanadate nanofibers (SVNF) and poly(3,4-ethylene dioxythiophene) (PEDOT) intercalated SVNF (E-SVNF) composites by a simple sonochemical approach for room temperature NH3 gas sensing and zinc ion battery (ZIB) studies. Applying E-SVNF to ZIBs resulted in superior rate capability, with a capacity of 192.13 mAh g−1 at 15 A g−1. Furthermore, they demonstrated long-term cycling stability, maintaining 83.47% of their capacity at 15 A g−1 even after 3,000 cycles. The gas sensor incorporating E-SVNF showcased a high response and excellent selectivity, even at room temperature, with response values of 1.059 for 10 ppm and 1.113 for 70 ppm of NH3 gas. These remarkable enhancements in the electrochemical performance of ZIBs and the gas sensor are attributed to the insertion of conductive polymers between SVNF layers. This resulted in improved electrical conductivity, increased interlayer distance in the vanadate nanofiber structure, enhanced layered structural stability, increased oxygen vacancies, a decreased work function, and the formation of p-p heterojunctions, all of which contribute to improved functionality of the composites materials. This research is expected to serve as a cornerstone for the development of industrial safety systems.

Reducing and tuning the work function of field emission nanocomposite CNT/NiO cathodes by modifying the chemical composition of the oxide.

This work presents for the first time the possibility of reducing and tuning the work function of field emission cathodes coated with metal oxides by changing the chemical composition of oxide coatings using an example of heat-treated CNT/NiO nanocomposite structures. These cathodes are formulated using carbon nanotube (CNT) arrays that are coated with ultrathin layers of nickel oxide (CNT/NiO) by atomic layer deposition (ALD). It was found that NiO at thicknesses of several nanometers grown on CNTs heat treated at a temperature of 350 °C can change its stoichiometric composition towards the formation of oxygen vacancies, since the Ni3+/Ni2+ peak area ratio increases and the position of the Ni-O peak binding energies shifts as observed using X-ray photoelectron spectroscopy (XPS). According to the secondary electron cut-off, the work function was 4.95 for pristine CNTs and it was found that the work function of deposited NiO layers on CNTs decreased after heat treatment. The decrease in work function occurs as a result of changes in the chemical composition of the oxide film. For the heat-treated CNT/NiO composites, the work function was 4.30 eV with a NiO layer thickness of 7.6 nm, which was less than that for a NiO thin film close to the stoichiometric composition, which had a work function of 4.48 eV. The field emission current-voltage characteristics showed that the fields for producing an emission current density of 10 μA cm-2 were 5.54 V μm-1 for pure nanotubes and 4.32 V μm-1 and 4.19 V μm-1 for NiO-coated CNTs (3.8 and 7.6 nm), respectively. The present study has shown that heat treatment of deposited thin NiO layers on field cathodes is a promising approach to improve the efficiency of field emission cathodes and is a new approach in vacuum nanoelectronics that allows tuning the work function of field emission cathodes.

First-principles study of Cs/O deposited Na<sub>2</sub>KSb photocathode surface

Na<sub>2</sub>KSb photocathodes have many applications in vacuum optoelectronic devices, such as photomultiplier tubes, image intensifiers, and streak image tubes for high-speed detection and imaging in extremely weak light environments, due to their advantages of high temperature resistance, small dark current, low vacuum requirement, low fabrication cost and high fabrication flexibility. In addition, this type of photocathode has important application prospect in high brightness accelerator photoinjectors. To guide the fabrication of high-sensitivity Na<sub>2</sub>KSb photocathodes, Na<sub>2</sub>KSb surfaces with different surface orientations and atom terminations are investigated by the first-principles calculation method based on the density functional theory to obtain the most stable and most favorable surface for electron emission. From the perspectives of surface energy, adsorption energy, and work function before and after Cs adsorption, it is revealed that the Na<sub>2</sub>KSb (111) K surface exhibits superior surface stability and electron emission capability. Furthermore, the electronic structure and optical properties of Cs adsorption and Cs/O co-adsorption on the Na<sub>2</sub>KSb (111) K surface under different Cs coverages are analyzed, and the mechanism of Cs/O deposition on Na<sub>2</sub>KSb surface is studied. The adsorption energy of Cs in the Cs/O adsorption model is much larger than that in the single Cs adsorption model, indicating that the adsorption of O atoms on the Na<sub>2</sub>KSb surface can make the adsorption of Cs atoms on the surface stronger, and thus increasing the adhesion of Cs atoms on the surface. After adsorption of Cs on the Na<sub>2</sub>KSb (111)K surface, the surface work function only decreases by 0.02 eV, while the maximum work function decrease for the Cs/O adsorbed surface is 0.16 eV, with the Cs coverage of 2/4 ML and the O coverage of 1/4 ML. The adsorption of Cs/O atoms on the surface facilitates the charge transfer above the surface and results in charge accumulation, which can form the effective surface dipole moment. The magnitude of the surface dipole moment is directly related to the change of work function. Furthermore, through the analysis of the electronic band structure and density of states, it is found that the adsorbed Cs atoms have additional contribution to the band structure near the conduction band minimum. After the introduction of O atoms, the valence band moves up, also the bottom of the conduction band and the top of the valence band become flat. The Cs/O deposition is beneficial to increasing the absorption of near-infrared light on the Na<sub>2</sub>KSb surface, but it will reduce the absorption of ultraviolet light and visible light, and the refractive index will also decrease. This work has a certain reference significance for understanding the optimal emission surface of Na<sub>2</sub>KSb photocathode and the mechanism of surface Cs/O deposition.

Effect of work function on dust charging and dynamics near lunar surface

Charged dust on the lunar surface poses a threat to space missions. Research into charged dust is essential for the safety of future space missions. The conventional lunar dust charging theory assumes a single constant work function when calculating the charging currents related to photoelectrons. However, the components of lunar regolith exhibit considerable diversity, including plagioclase, pyroxene, and ilmenite. Because the ability of the lunar surface or lunar dust to emit photoelectrons strongly depends on their work function, it is necessary to analyze the effect of work function on dust charging and dynamics near the lunar surface. In this work, we used a novel method that can predict the photoelectric yield of materials with different work functions to recalculate the surface charging currents of four types of dust particles and derived their subsequent charging and dynamic results at different solar zenith angles (SZAs). When SZA varies from 0°to 90°, the work function of dust decreases incrementally through four values: 6 eV (Apollo lunar soil), 5.58 eV (Plagioclase), 5.14 eV (Pyroxene), and 4.29 eV (Ilmenite). With each decrement in work function, the equilibrium charging currents of dust particles increase by approximately 0.5 times, the equilibrium charge numbers increase by approximately 120-170 elemental charges, and the equilibrium heights increase by approximately 0.3-2 m. We found that dust particles could not levitate stably at a critical SZA, and the critical SZAs for the four types of dust particles are 28°, 76°,85.8°, and 89.6°, respectively (arranged in order of decreasing work function). These results indicated that the equilibrium heights, equilibrium currents, and critical SZAs all have an inverse relationship with the work functions of dust particles as the SZA varies from 0°to 90°. In addition, a higher photoelectron density in areas with lower work functions results in smaller energy losses, causing dust particles to take longer to reach equilibrium, which means the equilibrium time follows the same pattern as that of the work function.

Dual-Use Self-Assembled Monolayer Controlling Charge Carrier Extraction in Organic Solar Cells.

The development and use of interface materials are essential to the continued advancement of organic solar cells (OSCs) performance. Self-assembled monolayer (SAM) materials have drawn attention because of their simple structure and affordable price. Due to their unique properties, they may be used in inverted devices as a modification layer for modifying ZnO or as a hole transport layer (HTL) in place of typical poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) in conventional devices. In this work, zinc oxide (ZnO) is modified using five structurally similar SAM materials. This resulted in a smoother surface, a decrease in work function, a suppression of charge recombination, and an increase in device efficiency and photostability. In addition, they can introduced asfor hole extraction layer between the active layer and MoO3 , enabling the use of the same material at several functional layers in the same device. Through systematic orthogonal evaluation, it is shown that some SAM/active layer/SAM combinations still offered device efficiencies comparable to ZnO/SAM, but with improved device' photostability. This study may provide recommendations for future SAM material's design and development as well as a strategy for boosting device performance by using the same material across both sides of the photoactive layer in OSCs.

Concurrent Thermal Reduction and Boron-Doped Graphene Oxide by Metal–Organic Chemical Vapor Deposition for Ultraviolet Sensing Application

We synthesized a boron-doped reduced graphene oxide (BrGO) material characterized by various electrical properties, through simultaneous thermal reduction and doping procedures, using a metal–organic chemical vapor deposition technique. X-ray photoelectron spectroscopy (XPS) was used to study the impact of the doping level on the B bonding in the reduced graphene oxide (rGO) layer that is influenced by the annealing temperature. The synthesized BrGO layer demonstrated a high B concentration with a considerable number of O-B bonds, that were altered by annealing temperatures. This resulted in a decreased work function and the formation of a Schottky contact between the BrGO and n-type Si substrate. Due to the higher proportion of B-C and B-C3 bonding in the BrGO/Si device than that in the rGO/Si, the decreased Schottky barrier height of the BrGO/n-Si vertical junction photodetector resulted in a higher responsivity. This study showcases a promise of a simple B-doping method in use to alter the electrical characteristics of graphene materials.

Polar Polymorphism: A New Intermediate Structure toward the Thin-Film Phase in Asymmetric Benzothieno[3,2-b][1]-benzothiophene Derivatives.

Understanding structure and polymorphism is relevant for any organic device optimization, and it is of particular relevance in 7-decyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) since high carrier mobility in Ph-BTBT-10 thin films has been linked to the structural transformation from the metastable thin-film phase to the thermodynamically stable bilayer structure via thermal annealing. We combine here a systematic nanoscale morphological analysis with local Kelvin probe force microcopy (KPFM) that demonstrates the formation of a polar polymorph in thin films as an intermediate structure for thicknesses lower than 20 nm. The polar structure develops with thickness a variable amount of structural defects in the form of individual flipped molecules (point defects) or sizable polar domains, and evolves toward the reported nonpolar thin-film phase. The direct experimental evidence is supported by electronic structure density functional theory calculations. The structure of the film has dramatic effects on the electronic properties, leading to a decrease in the film work function (by up to 1 eV) and a considerable broadening of the occupied molecular orbitals, attributed to electrostatic disorder. From an advanced characterization point of view, KPFM stands out as a valuable tool for evaluating electrostatic disorder and the conceivable emergence of polar polymorphs in organic thin films. The emergence of polar assemblies introduces a critical consideration for other asymmetric BTBT derivatives, which may be pivotal to understanding the structure-property relationships in organic field-effect transistors (OFETs). A precise determination of any polar assemblies close to the dielectric interface is critical for the judicious design and upgrading of high-performance OFETs.

Bimetallic metal-organic framework-derived bamboo-like N-doped carbon nanotube-encapsulated Ni-doped MoC nanoparticles for water oxidation

Molybdenum carbide materials with unique electronic structures have received special attention as water-splitting catalysts, but their structural stability in the alkaline water electrolysis process is not satisfactory. This study reports an in situ pyrolysis method for preparing NiMo-based metal-organic framework (MOF)-derived chain-mail oxygen evolution reaction (OER) electrocatalysts and bamboo-like N-doped carbon nanotube (NCNT)-encapsulated Ni-doped MoC nanoparticles (NiMoC-NCNTs). The NCNTs can provide chain mail shells to protect the inner highly reactive Ni-doped MoC cores from electrochemical corrosion by the alkaline electrolyte and regulate their catalytic properties through charge redistribution. Benefiting from high N-doping with abundant pyridinic moieties and abundant active sites of the periodic bamboo-like nodes, the as-prepared NiMoC-NCNTs display an outstanding activity for the OER with an overpotential of 310 mV at 10 mA cm−2 and a superior long-term stability of 50 h. Density functional theory calculations reveal that the excellent electrocatalytic activity of NiMoC-NCNTs comes from the electron transfer from NiMoC nanoparticles to NCNTs, resulting in a decrease in the local work function at the carbon surface and optimized free efficiencies of OER intermediates on C sites. This work provides an effective approach to improve the structural stability of fragile catalysts by equipping them with carbon-based chain.

Exploring Hafnium-induced transformations in SnSe allotropes: Insights into structural, electronic, optical, and mechanical modifications for enhanced optoelectronic utilization

In this comprehensive DFT study, we delve into the transformative influence of Hafnium (Hf) doping on the intrinsic properties of α − SnSe, β − SnSe, γ − SnSe, δ − SnSe, and ε − SnSe allotropes. By employing advanced analytical techniques, we elucidate the nuanced structural and electronic modifications, unveiling a potent potential for electronic application optimization. After doping, there's a consistent decrease in work function in all studied variations, suggesting a heightened electron release propensity. This discovery could have meaningful impacts, not only on the fields of electronics but also profoundly on the optoelectronic domain. The spotlight, however, shines intensely on the optical properties. Key parameters—including the dielectric function, absorption coefficient, refractive index, and reflectivity—undergo discernible shifts, especially in the δ-SnSe allotrope, emphasizing a broadened applicability spectrum. This optical versatility paves the way for SnSe's potential in solar cells, LEDs, photodetectors, optical modulators, and beyond. On the mechanical front, elasticity evaluations unearthed patterns of enhanced resilience, with Hf doping imparting increased in-plane stiffness, occasionally at the expense of ductility. In conclusion, our findings champion Hf-doped SnSe structures as promising contenders for groundbreaking optoelectronic devices, setting a foundation for future material innovation and application in contemporary technology.

Electrophysical properties of laser-structured carbon nanomaterials functionalized with LaB6 nanoparticles

In this paper, we perform density functional theory (DFT)-calculations to study the effect of LaB6 nanoparticles on the electrophysical properties of carbon nanomaterial based on laser-structured multi-walled carbon nanotubes (MWCNTs). Based on the calculation results, the most energetically favorable landing sites for LaB6 nanoparticles on the surface of the carbon framework are determined. It is found that during the functionalization with LaB6 nanoparticles, the carbon framework takes on a charge from the atoms of lanthanum and boron, which leads to an increase in the density of electronic states of the MWCNT nanostructure. It is shown that even at low concentrations of LaB6 nanoparticles (4.5 %), the work function of the carbon nanomaterial decreases by 0.5 eV. The results of the calculations are verified in the course of a real experiment. To carry it out, using the original technology of laser irradiation, a hybrid nanomaterial was created from a vertical array of MWCNTs functionalized with LaB6 nanoparticles. Pulsed laser action on an array of MWCNTs with an adjusted energy density of 0.15 J/cm2 made it possible to shorten, align, and orient the upper ends of the nanotubes perpendicular to the substrate. The effect of binding of LaB6 nanoparticles to a carbon surface has been experimentally established. Laser exposure of the MWCNT array coated with LaB6 nanoparticles resulted in a ∼ 5 by times increase in electrical conductivity compared to the original MWCNT array. Recording the emission current-voltage characteristics of hybrid nanomaterials demonstrated a decrease in the total work function of the carbon nanomaterial after functionalization with LaB6 nanoparticles by 16 %. Field emission current density values were calculated for all samples based on their measured field emission CVC characteristics. The MWCNT array exhibited the highest current density of 0.37 A/cm2 after LaB6 deposition and laser exposure. It is predicted that the carbon nanomaterial based on laser-structured MWCNTs coated with LaB6 nanoparticles will be an excellent nanomaterial for field emission electronics.

Distribution of hydrogen atoms at metallurgical microphases of X52 pipeline steel studied by scanning Kelvin probe force microscopy and finite element modelling

The work combined scanning Kelvin probe force microscopy measurements and finite element modelling to study the diffusion and distribution of hydrogen (H) atoms at metallurgical microphases contained in X52 pipeline steel. Results show that the pearlite contained in the steel is more stable than the ferrite during electropolishing, as indicated by the measured topographic profiles and Volta potentials. The hydrogen (H)-charging enhances the electrochemical activity of both pearlite and ferrite, as shown by increased Volta potential and thus the decreased work function. As the H-charging time increases, the Volta potentials of both phases further increase, implying that their activities increase with the H-charging time. The pearlite has a greater Volta potential and thus a lower work function than the ferrite. This is associated with more H atoms accumulating at the pearlite than at the ferrite. The H atom diffusion and accumulation are affected by H diffusivity at phase boundaries, H-trap binding energy and the number of traps in the steel.

Non-Conjugated Poly(Diphenylene Phthalide)-New Electroactive Material.

In organic electronics, conjugated conductive polymers are most widely used. The scope of their application is currently very wide. Non-conjugated polymers are used much less in electronics and are usually used as insulation materials or materials for capacitors. However, the potential of non-conjugated polymers is much wider, due to the fact that new electronic materials with unique electronic properties can be created on the basis of non-conjugated polymers, as well as other inorganic dielectrics. This article demonstrates the possibilities of creating electrically conductive materials with unique electronic parameters based on non-conjugated polymers. The results of the study of the sensory properties of humidity are given as examples of the practical application of the structure. The abnormal electronic properties are realized along the interface of two polymer dielectrics with functional polar groups. The submicron films of polydiphenylenephthalide were used as a dielectric. It is shown that a quasi-two-dimensional electronic structure with abnormally large values of conductivity and mobility of charge carriers occurs along the interface. These structures are often called quasi-two-dimensional electron gas (Q2DEG). This article describes the manufacturing processes of multielectrode devices. Polymer films are deposited via the spin-coating method with polymer solutions in cyclohexanone. The metal electrodes were manufactured through thermal deposition in a vacuum. Three types of metal electrodes made of aluminum, copper and chromium were used. The influence of the electron work function of contacting metals on the electronic parameters of the structure was studied. It was established that the work function decrease leads to an increase in the conductivity and mobility of charge carriers. The charge carrier parameters were estimated based on the analysis of the current-voltage characteristics within the space-charge-limited current technique. The Richardson-Schottky thermionic emission model was used to evaluate values a potential barrier at metal/organic interfaces. It was established that the change in ambient humidity strongly affects the electronic transport properties along the polymer/polymer interface. It is demonstrated that the increase in conductivity with an increase in humidity occurs due to an increase in the mobility of charge carriers and a decrease in the height of the potential barrier at the three-dimensional metal contact with two-dimensional polymer interface. The potential barrier between the electrode and the bulk of the polymer film is significantly higher than between the electrode and the quasi-two-dimensional polymer structure.

Direct Observation of Contact Reaction Induced Ion Migration and its Effect on Non-Ideal Charge Transport in Lead Triiodide Perovskite Field-Effect Transistors.

The migration of ionic defects and electrochemical reactions with metal electrodes remains one of the most important research challenges for organometal halide perovskite optoelectronic devices. There is still a lack of understanding of how the formation of mobile ionic defects impact charge carrier transport and operational device stability, particularly in perovskite field-effect transistors (FETs), which tend to exhibit anomalous device characteristics. Here, the evolution of the n-type FET characteristics of one of the most widely studied materials, Cs0.05 FA0.17 MA0.78 PbI3, is investigated during repeated measurement cycles as a function of different metal source-drain contacts and precursor stoichiometry. The channel current increases for high work function metals and decreases for low work function metals when multiple cycles of transfer characteristics are measured. The cycling behavior is also sensitive to the precursor stoichiometry. These metal/stoichiometry-dependent device non-idealities are correlated with the quenching of photoluminescence near the positively biased electrode. Based on elemental analysis using electron microscopy the observations can be understood by an n-type doping effect of metallic ions that are created by an electrochemical interaction at the metal-semiconductor interface and migrate into the channel. The findings improve the understanding of ion migration, contact reactions, and the origin of non-idealities in lead triiodide perovskite FETs.

Interlayer Electrons Polarization of Asymmetric Metal Nanoclusters/g-C3 N4 for Enhanced Microwave Therapy of Pneumonia.

Interlayer interactions in two dimensional (2D) materials promote catalytic performance but often depend on the transport of inter rather than intralayer electrons. In this study, it is found that asymmetric metal-nanocluster-doped 2D g-C3 N4 greatly enhances catalytic performance by inducing microwave excitation of interlayer electron delocalization, resulting in a polarization of interlaminar charge transport for microwave disinfection and pneumonia therapy. Asymmetric Fe and Cu nanocluster doping (DCN-FeCu) enables g-C3 N4 to generate interlayer electrons under microwave irradiation, leading to interlayer polarization processes and electron delocalization effects, thus enhancing the interlayer migration efficiency of electrons. It also improves impurity energy levels and leads to a decrease in work function, allowing DCN-FeCu to produce microwave carriers across the photoelectric potential barrier under low-energy microwave radiation (2.45GHz). This asymmetric doping modulation produces layer number-dependent microwave electron excitations that are verified using multi-metal doping. Therefore, structurally modulated asymmetric doping of 2D materials with interfacial spatial effects can provide efficient microwave disinfection and pneumonia therapy.