Charge Transport Mechanism Research Articles

Radical polymers in optoelectronic and spintronic applications

Radical polymers hold great potential as solid-state conducting materials due to their distinctive charge transport mechanism and intriguing optical and spintronic properties resulting from their singly occupied molecular orbital energy levels.

Recent developments of artificial intelligence in MXene-based devices: from synthesis to applications.

Two-dimensional transition metal carbides, nitrides, or carbonitrides (MXenes) have garnered remarkable attention in various energy and environmental applications due to their high electrical conductivity, good thermal properties, large surface area, high mechanical strength, rapid charge transport mechanism, and tunable surface properties. Recently, artificial intelligence has been considered an emerging technology, and has been widely used in materials science, engineering, and biomedical applications due to its high efficiency and precision. In this review, we focus on the role of artificial intelligence-based technology in MXene-based devices and discuss the latest research directions of artificial intelligence in MXene-based devices, especially the use of artificial intelligence-based modeling tools for energy storage devices, sensors, and memristors. In addition, emphasis is given to recent progress made in synthesis methods for various MXenes and their advantages and disadvantages. Finally, the review ends with several recommendations and suggestions regarding the role of artificial intelligence in fabricating MXene-based devices. We anticipate that this review will provide guidelines on future research directions suitable for practical applications.

High-temperature sensitivity complex dielectric/electric modulus, loss tangent, and AC conductivity in Au/(S:DLC)/p-Si (MIS) structures

Complex dielectric (ε* = ε′ − jε″)/electric modulus (M* = M′ + jM″), loss tangent (tanδ), and ac conductivity (σac) properties of Au/(S-DLC)/p-Si structures were investigated by utilizing admittance/impedance measurements between 80 and 440 K at 0.1 and 0.5 MHz. Sulfur-doped diamond-like carbon (S:DLC) was used an interlayer at Au/p-Si interface utilizing electrodeposition method. The capacitance/conductance (C/G) or (ε' ~ C) and (ε″ ~ G) values found to be highly dependent on both frequency and temperature. The increase of them with temperatures was attributed to the thermal-activated electronic charges localized at interface states (Nss) and decrease in bandgap energy of semiconductor. The observed high ε′ and ε″ values at 0.1 MHz is the result of the space/dipole polarization and Nss. Because the charges are at low frequencies, dipoles have sufficient time to rotation yourself in the direction of electric field and Nss can easily follow the ac signal. Arrhenius plot (ln(σac) vs 1/T) shows two distinctive linear parts and activation energy (Ea) value was found as 5.78 and 189.41 from the slope; this plot at 0.5 MHz is corresponding to low temperature (80–230 K) and high temperature (260–440 K), respectively. The observed higher Ea and ε′ (~ 14 even at 100 kHz) show that hopping of electronic charges from traps to others is predominant charge transport mechanism and the prepared Au/(S:DLC)/p-Si structure can be used to store more energy.

Organic Mixed Ionic-Electronic Conductors for Bioelectronic Sensors: Materials and Operation Mechanisms.

The field of organic mixed ionic-electronic conductors (OMIECs) has gained significant attention due to their ability to transport both electrons and ions, making them promising candidates for various applications. Initially focused on inorganic materials, the exploration of mixed conduction has expanded to organic materials, especially polymers, owing to their advantages such as solution processability, flexibility, and property tunability. OMIECs, particularly in the form of polymers, possess both electronic and ionic transport functionalities. This review provides an overview of OMIECs in various aspects covering mechanisms of charge transport including electronic transport, ionic transport, and ionic-electronic coupling, as well as conducting/semiconducting conjugated polymers and their applications in organic bioelectronics, including (multi)sensors, neuromorphic devices, and electrochromic devices. OMIECs show promise in organic bioelectronics due to their compatibility with biological systems and the ability to modulate electronic conduction and ionic transport, resembling the principles of biological systems. Organic electrochemical transistors (OECTs) based on OMIECs offer significant potential for bioelectronic applications, responding to external stimuli through modulation of ionic transport. An in-depth review of recent research achievements in organic bioelectronic applications using OMIECs, categorized based on physical and chemical stimuli as well as neuromorphic devices and circuit applications, is presented.

(Invited) Unravelling Structural Implications on Charge Transport Mechanism in Nanostructured Electrode Materials for Energy Storage Devices

The development of new and novel electrode materials for energy storage devices has become the intensive research by the materials science community because of its importance in the portable electronic devices, hybrid electric vehicles and many other applications. Since the discovery by Goodenough and his co-workers on the electrochemical behavior of olivine LiFePO4 (LFP), different theoretical and experimental investigations have been undertaken to optimize it as cathode material in lithium-ion batteries and trying to understand the charge/discharge mechanism. Despite having many fascinating electrochemical properties, the main drawback of LFP lies with its low gravimetric density and poor electrical conductivity (both electronic and ionic) which limits the lithium intercalation/deintercalation rates, and hence the practical specific capacity. Therefore, it becomes necessary to gain the fundamental understanding of electronic structure of the LFP system by adopting appropriate experimental technique. We exploit the combined Mössbauer and X-ray absorption spectroscopy to unravel the electronic structure and local site symmetry of Fe in olivine structured LFP with different crystallite sizes (CS). The lattice parameters are found to contract with decrease in CS monotonously, whereas the electronic structural parameters exhibit two different regions with threshold anomaly around ≈30 nm CS. The 57Fe Mössbauer studies reveal the coexistence of Fe2+ and Fe3+sites and their relative concentration are mainly determined by the CS, which provides the comprehensive insight into the electronic structure of LFP at mesoscopic level. The soft X-ray absorption unravels unequivocally the valance states of Fe 3d electrons in the proximity of Fermi level, which are prone to the local lattice distortion. An obtained spectra fingerprint the effect of CS supplying rich information on valence state of iron, lithium-ion vacancy concentration, covalency and crystal field. The unique structural and electronic properties of the LFP are closely interlinked with changes in the bonding character, which shows the strong dependency on the CS. The evolution of the 3d states is in overall agreement with the local lattice distortion and provides the origin of the size effects on the electronic structure olivine phosphate and other transition metal ion containing materials. We observe polaronic conductivity enhancement of approximately two orders of magnitude at the nanoscale level as compared with its bulk counterpart. The volumetric changes with respect to crystallite size are related to the compressive strain resulting into the improvement in the electronic diffusivity. The nano-crystalline LFP with better kinetics will open the new avenue for its usage as cathode material in rechargeable batteries.

(Invited) Transparent Conductive Films of PEDOT:PSS-Amino Acid Composite

Transparent conductive electrode is an important component of optoelectronic devices such as light emitting diodes, photodiodes, and photovoltaic cells as well touchscreen technology. Growing demand for these technologies, as well as need for functionalities such as cost-effectiveness and flexibility, has resulted in various research on developing organic polymer-based transparent electrodes as an alternative to indium tin oxide (ITO) which is the current industry standard. One of the organic conducting polymers most commonly studied for their potential to be used as ITO-free transparent electrodes is PEDOT:PSS due to its high transmittance as a thin film, solution processability, flexibility, environmental stability, and commercial availability. There have been various works carried out to improve the conductivity of the PEDOT:PSS-based thin films by introducing dopants to improve the charge transport. We present our results demonstrating that not only the conductivity but also the transmittance of PEDOT-PSS-based films can be significantly improved by the introduction of amino acids such as phenylalanine in the film. We have observed that this enhancement in conductivity and optical transmittance of PEDOT:PSS-phenylalanine composite film is retained even when the amount of amino acid in the composite films is larger than the amount of PEDOT:PSS. We will present our study on the charge transport mechanism on these films based on electrochemical impedance spectroscopy (EIS) measurements. We will also further present our studies based on Scanning Electron Microscopy (SEM) as well as Scanning Probe Microscopy techniques such as topography imaging and conducting probe atomic force microscopy (CP-AFM) to elucidate the relationship between film morphology and charge transport in these composite films. The use of bioderived materials such as amino acids to create transparent composite films could open up avenues for developing and integrating bio-based materials in future electronics, help improve the environmental footprint of the electronics, and potentially also allow for the development of materials with a higher degree of biocompatibility for their application in bioelectronics.

Simultaneous Optical and Electrical Monitoring of Charge Percolation in Flow Electrodes

Electrochemical reactions are limited to the surface of the electrode, which makes the construction and intensification of electrochemical processes challenging. To increase the space-time yield of electrochemical cells, the electrochemically active surface area has to be enlarged. This can be achieved by either increasing the surface of a fixed electrode (e.g., porous electrodes) or by so-called flow electrodes. Flow electrodes consist of conductive particles suspended in the electrolyte. They have the advantage of increasing the active surface area of the electrode and also enabling continuous recycling and exchange of the active electrode material. They have been successfully applied, for example, for energy storage in redox flow batteries and desalination in flow-electrode capacitive deionization (FCDI).In flow electrodes the conductive particles dynamically increase the active area of the electrode by collision with the electrode; however, the exact mechanism of charge transport in such suspensions, also called charge percolation, is not completely understood. Yet, the successful implementation of flow electrodes in electrochemical processes requires a deeper understanding of how these particles interact within the electrochemical system. Charge percolation in flow electrodes is highly dynamic, and the conductivity of the suspensions depends on multiple factors like the amount and position of the particles, the shape and accessibility of the current collector, and especially the contact between particles and current collector. Literature presents different approaches which deal with charge transport in conductive suspensions, either by analyzing the electrical properties of flow electrodes in flow or by examining the structure and position of the particles visually in static conditions. We combine visual and electrical in-situ monitoring of charge percolation events in a single experimental setup. We developed a transparent electrochemical flow cell, made of transparent polydimethylsiloxane (PDMS), allowing for in-situ measurements. A constant voltage is applied to the current collector by a potentiostat. The resulting electrical current is measured simultaneously by recoding the particle movements using an optical microscope and a high-speed camera. The design of the electrochemical cell enables different positions of the particles within the channel in different flow modes: Contact between particles and the current collector can be either prevented or enforced. A motion-tracking algorithm analyses the videos to determine the area of particles in the electric field and the area of particles contacting the current collector. This allows for the correlation of particle behavior and electrical current.We investigated the influence of electrolyte, particle fraction, and the contact probability of particles and current collector on charge transport. Our results show that contact between particles and the current collector is a main contributor to charge transport in flow electrodes. But particles cluster can also increase the current, even if they do not touch the current collectors. The highest increase in current was achieved for large particle fraction short circuiting both current collectors. These results show that the way the particle suspension interacts with the electrode and by guiding the flow the electrochemical processes can be improved dramatically.

Tailoring the electrical conductivity of Poly(vinylidene fluoride) by blending with poly (3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) and ionic liquids

In order to tailor dielectric response and electrical conductivity, novel polymer blends based on poly(vinylidene fluoride (PVDF) and different fillers composed by poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), and PEDOT:PSS/ionic liquids (ILs): PEDOT:PSS/N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C2mpyr][FSI]) and PEDOT:PSS/N-ethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([C2mpyr][TFSI]), with different PEDOT:PSS/IL contents (10, 20 and 40 wt%) were prepared through solvent casting. The morphological, physical-chemical and thermal properties of the polymer blends were evaluated, together with the influence of PEDOT:PSS/IL on the PVDF crystallization kinetics, dielectric and electrical conductivity.The incorporation of PEDOT:PSS/IL in the polymer matrix lead to a decrease of the PVDF spherulites. Furthermore, it was detected that both PEDOT:PSS and IL act as nucleation agents, promoting the homogeneous crystallization of PVDF as well as the crystallization into its b and g polar phases. The electrical conductivity formalism revealed significant contributions of PEDOT:PSS/IL to the electrical conductivity behavior of the blends, being thermally activated and described by the charge transport mechanism. Further, the dc conductivity increases due to the higher number of charge carriers of the PEDOT:PSS/IL content.The tailorable electrical characteristics of the PVDF/PEDOT:PSS-IL blends demonstrate their potential for applications in areas such as ionic actuators and battery devices.

Visualization of Mesoscopic Conductivity Fluctuations in Amorphous Semiconductor Thin-Film Transistors.

Charge transport in amorphous semiconductors is considerably more complicated than the process in crystalline materials due to abundant localized states. In addition to device-scale characterization, spatially resolved measurements are important to unveiling electronic properties. Here, we report gigahertz conductivity mapping in amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors by microwave impedance microscopy (MIM), which probes conductivity without Schottky barrier's influence. The difference between the dc and microwave conductivities reflects the efficacy of the injection barrier in an accumulation-mode transistor. The conductivity exhibits significant nanoscale inhomogeneity in the subthreshold regime, presumably due to trapping and release from localized states. The characteristic length scale of local fluctuations, as determined by the autocorrelation analysis, is about 200 nm. Using a random-barrier model, we can simulate the spatial variation of the potential landscape, which underlies the mesoscopic conductivity distribution. Our work provides an intuitive way to understand the charge transport mechanism in amorphous semiconductors at the microscopic level.

Moisture-modulated resistive switching behavior based on CaTiO3 prepared by the appropriate NaOH concentration

It is well known that the multi-mode responsive memristor has a great application prospect in the complex environment. The CaTiO3-based memristor was prepared under different NaOH concentrations, which exhibited an obvious resistive switching (RS) behavior at the working voltage of 1 V. The experimental results indicate that the purity of CaTiO3 is affected by different NaOH concentrations, leading to changes in its microstructure. Interestingly, moisture as an electrical stimulus can change the RS behavior. By comparison, a large memory window with stable cycling performance can be observed at the relative humidity (RH) of 60%. A physical model, which involves Ag+ ions, oxygen vacancy (Vo) and OH− ions, was proposed to explain the charge transport mechanism of the moisture-modulated RS behavior. As an effective method to improve the memristive characteristics, the moisture-modulated RS behavior provides a great application for multi-mode-controlled memristor in physiological monitoring, such as sweat and infant urine monitoring.

Fe dopant controlled the ferromagnetic, structural, thermal, optical, and electrical characteristics of CdO nanoparticles

This research paper presents a study on (Fe) doped CdO nanoparticles focusing on their structural (XRD), thermal (TGA and DTA), optical (UV–vis), magnetic (VSM and ESR), and electrical characteristics. The synthesis of Cd1-xFexO with (x = 0.0, 0.01, 0.05, 0.10, 0.15, and 0.20) nanoparticles was carried out using the co– precipitation technique. Fe dopants showed a great impact on the structural parameters and the thermal stabilities of obtained nanomaterials. SEM and TEM imaging techniques are employed to investigate the morphology, size, and distribution of the Cd1-xFexO nanoparticles. UV spectroscopy was employed to better understand the electronic transitions and optical characteristics. Furthermore, magnetization measurements from ESR and VSM showed a weak ferromagnetic order with a high Fe concentration. For instance, the Ac electrical conductivity measurements were used to determine the electrical properties, dielectric losses, and charge transport mechanisms between the Fe-dopants and CdO. The structural, thermal, optical, magnetic, and electrical characteristics data are complemented to better understand for Cd1-xFexO materials for employing them in magnetic storage and sensors, photocatalysis, other future applications.

Dielectric Analysis of Blended Polysulfone/Polyethylenimine Membrane Contactors for CO2 Capture.

Polysulfone membranes, used as contactors for CO2 capture, are blended with two different hyperbranched polyethyleneimines modified with benzoyl chloride (Additive 1) and phenyl isocyanate (Additive 2) in different percentages. Fourier-transformed infrared spectra evidence the presence of urea and amide groups, whereas the field emission scanning electron microscopy images show differences in the microstructure of the blended membranes. Dielectric spectra determine the motions of the side and backbone chains, which can facilitate the diffusion of CO2 . The spectra consist of six dielectric processes; three of them are due to the polysulfone (γPSf , βPSf , and αPSf ), whereas the rest are characteristic of the additive (γHPEI , βHPEI , and αHPEI ). The benzoyl chloride and phenyl isocyanate functional groups introduce variations in molecular mobility and modify the relaxations associated with the hyperbranched polyethyleneimine (HPEI). The additives also increase the conductivity of the blended membranes, which can compromise the performance of the membranes, specifically in the case of Additive 1. Ion hopping is found to be the prevailing charge transport mechanism while both relaxations, αHPEI and αPSf , are actives. These results, together with the final morphology of the membranes, may explain the greater absorption capacity of the membranes prepared with the hyperbranched polyethyleneimine modified with Additive 2.

Dielectric relaxation and conductivity phenomena in ferroelectric ceramics at high temperatures

The issues related to microstructure and its effects on functional properties of electroceramics become increasingly prominent with the progressive downscaling of electronics. In this study, temperature-dependent dielectric and impedance data of BaTiO3 (BT), Sr-doped BT (BST) and layer-structured BaBi4Ti4O15 (BBTO) ceramics are systematically investigated to reveal the effects of doping and perovskite layering on the dielectric relaxation and conduction processes at high temperatures. By using complex impedance spectroscopy, it is demonstrated that the ceramics are electrically heterogeneous structures displaying a non-ideal Debye-like behavior at high temperatures. Using a suitable equivalent circuit model, the impedance diagrams at different temperatures are simulated and the refined values of macroscopic resistance and capacitance are used for the identification and characterization of particular microstructural regions (grains, grain boundaries, interfaces, etc.). The approach of combining the impedance, electric modulus and permittivity formalisms is demonstrated to be effective in explaining the peculiarities of the electrical charge transport mechanism and relaxation in the grains, grain boundaries and interface layers of the ceramics.

Self-powered solution-processed photodetectors utilizing FAPbBr3:C60 bulk heterojunction

Hybrid halide perovskites have emerged as pivotal optoelectronic materials due to their easy and cost-effective solution-based manufacturing processes. In this study, we have combined formamidinium lead bromide (FAPbBr3) with buckminsterfullerene (C60) to create the bulk heterojunction (BHJ) photoactive layer for solution-processed photodetectors. Remarkably, the FAPbBr3:C60 BHJ-based photodetectors exhibited a substantial enhancement in optoelectronic performance, with the responsivity increasing from 0.87 A/W to 1.47 A/W compared to the pristine FAPbBr3. This improvement can be attributed to the superior surface morphology and crystallinity of the FAPbBr3:C60 BHJ thin film, which facilitated enhanced charge transport properties. Furthermore, the fabricated photodetectors demonstrated remarkable detectivity even at 0V, enabling self-powered operation. By employing the space charge limited conduction (SCLC) model, we were able to elucidate the dominant charge transport mechanism. At lower voltages, trap-free SCLC was identified as the primary mechanism, while traps governed charge transport at higher voltages. Additionally, we conducted impedance analysis to investigate the underlying factors contributing to the distinctive optoelectronic performance observed in the photodetectors.

Tailoring frequency/temperature independent colossal dielectric constant in Zn-doped Fe3O4/Fe2O3@C/PANI using phase co-existence approach

Introducing doped binary oxides to polymers offers a promising way towards advancement of charge density/energy storage materials with colossal dielectric constant. However, the origin of colossal dielectric constant explored in terms of conduction mechanism with a deeper understanding of the coexistence of phases/interfaces in these materials still requires much attention. In this context, we synthesised Zn-doped Fe3O4/Fe2O3@C/PANI composite that exhibits frequency and temperature independent colossal dielectric constant over a broad range, 1 Hz to 10 MHz and 93 K to 333 K, respectively. We analyzed the impedance data using an equivalent circuit model and Cole-Cole fitting to gain insight into the colossal dielectric response and low dielectric loss. The relaxation phenomenon corresponding to a highly stable electroactive region is validated by the distribution of relaxation time (DRT). Furthermore, the composite exhibited a non-relaxor-like behavior due to diffuse phase transition near semiconductor-to-metallic transition (SMT), observed at 303 K. The charge carriers follow the variable range hopping (VRH) and Arrhenius models yielding localization length of 3 Å and activation energy of 35 meV, which supports the charge transport mechanism between like cation interfaces. This detailed analysis covering the frequency and temperature independent dielectric constant along with the understanding of relaxation and conduction phenomena could provide a viable approach towards producing charge density/energy storage devices for practical applications.

Insights into structural, electronic, optical properties, and impedance spectroscopy of semi-doped perovskite Nd0.5Ba0.5CoO3: A theoretical and experimental study

In this study, the electronic, structural, and optical properties of semi-doped perovskite Nd0.5Ba0.5CoO3 (NBCO) were investigate using the CASTEP software, which relies on density functional theory (DFT) along with the correlation function of generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof (PBE). The mesh parameters of the (super) cell indicate that NBCO adopts an orthorhombic structure in the Pmmm space group, featuring a Coulomb Energy (EC) of approximately −244 eV. DFT and total density of states (DOS) analyses reveal that the as-prepared perovskite manifests metallic characteristics, and a notable covalent interaction is observed between the O-p and Co-d spin states, indicating strong hybridization between these orbitals. Remarkably, NBCO demonstrates 100 % spin polarization (P) at the Fermi level, with a calculated total magnetic moment of approximately 3.44 μB. Moreover, low dielectric loss (tgδ) values suggest facile electron movement, and impedance spectroscopy illustrates a dielectric relaxation phenomenon. DFT calculations predict an orthorhombic crystal structure with higher electron density at cobalt atom positions. Band structure and DOS analyses affirm metallic behavior owing to the robust hybridization between oxygen-p and cobalt-d orbitals. Optical property assessments reveal potential applications in spintronics and optoelectronics, with notable absorption in the ultraviolet–visible range. The conductivity spectra from impedance spectroscopy contribute to understanding temperature-dependent charge transport mechanisms. Dielectric constants decrease with increasing frequency and temperature, while dielectric losses remain low, indicating efficient electron movement. The material adheres to a metallic conduction mechanism as described by Drude's law, and the material's 100 % spin polarization at the Fermi level and a total magnetic moment of 3.44 μB are significant findings. Negative dielectric constants observed at specific frequencies suggest potential applications in metamaterials. Overall, the determined properties position NBCO cobaltite as a promising candidate for high-frequency devices, spintronic components, and sensors.

Toward Understanding the Spectroscopic Performance and Charge Transport Mechanisms of Methylammonium Lead Tribromide Perovskite X- and γ-Rays Detectors

Toward Understanding the Spectroscopic Performance and Charge Transport Mechanisms of Methylammonium Lead Tribromide Perovskite X- and <i>γ</i>-Rays Detectors

Synthesis and electrical properties of PANI/CeO2 nanocomposites: A study on the fluctuation-induced tunneling conduction

This study presents the preparation of PANI/CeO2 nanocomposites via in situ chemical oxidative polymerization in an acidic environment at subzero temperatures to optimize nanocomposite properties. Two compositions of PANI/CeO2, with 2% and 5% CeO2 nanoparticles, were synthesized and characterized structurally using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The temperature-dependent electrical conductivity was measured employing the four-probe technique and analyzed theoretically using the fluctuation-induced tunneling (FIT) model. The analysis of variance (ANOVA) confirmed the validity of the FIT model in elucidating charge transport mechanisms within the PANI/CeO2 composites.

Enhancing Z-scheme photocatalytic CO2 methanation at extended visible light (>600 nm): Insight into charge transport and surface catalytic reaction mechanisms

This article reports Z-scheme photocatalytic CO2 methanation at the extended visible light (>500 nm) in absence of sacrificial electron donor/acceptor and noble metal cocatalysts. This Z-scheme photocatalyst consists of reduced graphene oxide (rGO) sandwiched between two different redox active photocatalysts (Ca-doped Bi2O3 and Cu2O). The rGO acts as a mediator by relaying electrons from Ca-doped Bi2O3 and holes from Cu2O that enables Z-scheme spatial confinement of electrons in Cu2O while holes in Ca-doped Bi2O3. This charge carrier delocalization enforces the enhanced oxidation strength of holes in Ca-doped Bi2O3 and reduction strength of electrons in Cu2O. As a result, it has exhibited methane (CH4) production rate under wider range of visible light (up to 700 nm) absorption. This Z-scheme photocatalyst therefore advents a new ‘600 nm-class photocatalyst’ for CO2 methanation. With the help of 13C isotopic measurements, first principles calculations and photoelectrochemical measurements, we have revealed the atomistic insight into the charge transport and surface catalytic reactions mechanisms to understand the rate limiting factors towards unassisted PCR.

Direct current conductance and 1/f-noise in cellulose nanofiber–multi-walled carbon nanotube composites for applications in flexible electronic devices

We report on the studies of conduction mechanism, direct current conductance, and 1f-noise of cellulose nanofiber (CNF) and multiwalled carbon nanotube (MWCNT) composites. The composites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The temperature- and voltage-dependence of the dc conductance Σ were, respectively, probed to investigate the charge transport mechanism and the electrical response of the composite. At room temperature, the increase in Σ with wt. % of MWCNT ϕ showed typical percolation behavior. The Σ−T behavior was fitted to the combination of one-dimensional variable range hopping and the fluctuation-induced tunneling, which were attributed to hopping of charge carriers through 1D MWCNTs and the tunneling of charge carriers between the bundles of MWCNTs, respectively. The non-Ohmic electrical conduction was characterized by the onset voltage V0(T) which scaled with Ohmic conductance Σ0 as V0(T)∼Σ0(T)xT, with xT being the onset exponent increased with ϕ. A scaling description based on the data collapse method was adopted to find the parameters V0(T) and xT. The noise power spectrum SV(f) followed the relation SV(f)∼Vβ with two different power-laws: β1 in the Ohmic and β2 in the non-Ohmic region (β1&amp;gt;β2). Interestingly, this change in power-laws occurs at the same V0(T) obtained from Σ−V curves. A simple model was proposed to explain the noise behavior after V0(T). It is expected that such electrical characterization of CNF-MWCNT nanopaper composite would open up their possibility of application in flexible electronic devices, intelligent networks, sensors, and actuators.