Electrode Contact Research Articles

Enhancing the Efficiency of PM6:Y6 Bulk-Heterojunction Organic Solar Cells through SCAPS Simulation Optimization

Organic solar cell (OSC) is becoming a point of attraction in the solar cell industry due to their benefits, such as light weight, flexibility, low cost, semi-transparency, and easy fabricating methods. By replacing fullerene with non-fullerene acceptors like Y6, ITIC, PCBM, and ICBA, the power conversion efficiency (PCE) of OSCs has surpassed the 15% benchmark. Here, the proposed OSC structure includes an ITO front contact electrode, SnO2 electron transport layer (ETL), PM6:Y6 active layer, Cu2O hole transport layer (HTL), and Ag back contact electrode. Systematic numerical simulation of the above proposed OSC has been performed using a solar cell capacitance simulator (SCAPS)-1D (Version 3.3.09). The device improvement analysis has been carried out in steps by analyzing the ETL-HTL effect, selecting the optimum thickness of the active layer, and the optimum value of defect density. In the first step, a PCE of 24.60% was achieved, followed by an improvement to 27.55% with the optimized defect density value. The best PCE of 27.74% was achieved in the third step with an optimized active layer thickness, leading to high fill factor (80.56%), open-circuit voltage (0.9461 V), and short-circuit current density (36.188 mA/cm2). These simulated results promote an in-depth understanding of the optical and electronic properties of PM6:Y6 blend-based OSC and show the potential of NFA-BHJ OSCs as promising candidates for solar cells in the near future.

Precordial electrocardiographic recording and QT measurement from a novel wearable ring device

BackgroundThe availability of portable and wearable electrocardiography devices has increased secondary to technological development. Single-lead ECG recordings have been shown to reliably detect and characterize cardiac rhythms such as atrial fibrillation. Acquisition of precordial electrodes for full 12-lead ECG reconstruction from bipolar recordings is complicated by the absence of a body ground / Wilson central terminal electrode, however the extent of difference between standard precordial lead and those from a wearable bipolar ECG recorder has not been characterized. ObjectiveThis study characterizes precordial ECG lead set from sequential bipolar recordings from an ECG ring wearable device. MethodsIn 70 patients wearing an ECG device on their right finger, sequential precordial leads (CR1-CR6) were obtained along with chest electrodes (V1-V6). During acquisition of the modified precordial lead CR6 a full standardized 12 lead ECG capture was obtained.Using automated analysis software, signal quality was assessed, and the correlation values between the ring-derived ECG precordial leads and standard ECG leads were compared with QRS duration, QT width, and RR interval measurement. ResultsThere is high concordance in the morphology of precordial ECG leads obtained in a standard fashion and those recorded through an ECG ring. Morphologic alignment improved with increasing laterality of the precordial lead with chest to right arm ring recording (CR5, CR6) compared with anterior chest leads to right arm (CR1, CR2). Segmental measurements of QRS duration and QT segment were well aligned and of high correlation. ConclusionWearable ring based electrocardiographic technology is capable of high fidelity recording of precordial leads for non-simultaneous reconstruction of complete ECG sets. These correlate highly with surface-obtained QRS and QT duration measurement, which has significant implications for clinical applications. Uninterpretable tracings were primarily due to electrode noise from poor electrode contact.

Video-based sympathetic arousal assessment via peripheral blood flow estimation.

Electrodermal activity (EDA) is considered a standard marker of sympathetic activity. However, traditional EDA measurement requires electrodes in steady contact with the skin. Can sympathetic arousal be measured using only an optical sensor, such as an RGB camera? This paper presents a novel approach to infer sympathetic arousal by measuring the peripheral blood flow on the face or hand optically. We contribute a self-recorded dataset of 21 participants, comprising synchronized videos of participants' faces and palms and gold-standard EDA and photoplethysmography (PPG) signals. Our results show that we can measure peripheral sympathetic responses that closely correlate with the ground truth EDA. We obtain median correlations of 0.57 to 0.63 between our inferred signals and the ground truth EDA using only videos of the participants' palms or foreheads or PPG signals from the foreheads or fingers. We also show that sympathetic arousal is best inferred from the forehead, finger, or palm.

The Influence of Electrode Plate Area in Reducing Turbidity and Color Levels in Peat Water

Peat water generally exhibits characteristics ranging from dark brown to black, with high organic content and a pH range between 3.7 and 5.3. These features pose challenges in meeting clean water quality standards, essential for maintaining human health. Consequently, the treatment of peat water becomes a pressing need to enhance its quality for suitable use. Electrocoagulation has emerged as a widely applied method in peat water treatment. This research aims to evaluate the influence of electrode plate area and contact time in reducing turbidity and color in peat water. The research methodology employed a quasi-experimental design known as the One-Group Pretest-Posttest. Thirty test samples were collected with variations in electrode plate areas of 4 x 30 cm, 5 x 30 cm, and 6 x 30 cm. Contact time was varied within the range of 30, 60, 90, 120, and 150 minutes, applying a voltage of 48 volts. The results indicated fluctuations in the increase of turbidity in peat water after the electrocoagulation treatment. A plate area of 6 x 30 cm led to a turbidity increase of 27.33 NTU or approximately 83% after a contact time of 150 minutes. Meanwhile, the color level in peat water decreased by 65 TCU with a 5 x 30 cm electrode plate area after 150 minutes of contact time, achieving an effectiveness of 90% in color reduction. In conclusion, the electrode plate area significantly influences the reduction of turbidity and color in peat water. Although there is no discernible effect of contact time on turbidity levels, prolonged contact time has a significant impact on reducing the color level in peat water.

Amelioration of Parkinsonian tremor evoked by DBS: which role play cerebello-(sub)thalamic fiber tracts?

BackgroundCurrent pathophysiological models of Parkinson’s disease (PD) assume a malfunctioning network being adjusted by the DBS signal. As various authors showed a main involvement of the cerebellum within this network, cerebello-cerebral fiber tracts are gaining special interest regarding the mediation of DBS effects.ObjectivesThe crossing and non-decussating fibers of the dentato-rubro-thalamic tract (c-DRTT/nd-DRTT) and the subthalamo-ponto-cerebellar tract (SPCT) are thought to build up an integrated network enabling a bidimensional communication between the cerebellum and the basal ganglia. The aim of this study was to investigate the influence of these tracts on clinical control of Parkinsonian tremor evoked by DBS.MethodsWe analyzed 120 electrode contacts from a cohort of 14 patients with tremor-dominant or equivalence-type PD having received bilateral STN-DBS. Probabilistic tractography was performed to depict the c-DRTT, nd-DRTT, and SPCT. Distance maps were calculated for the tracts and correlated to clinical tremor control for each electrode pole.ResultsA significant difference between “effective” and “less-effective” contacts was only found for the c-DRTT (p = 0.039), but not for the SPCT, nor the nd-DRTT. In logistic and linear regressions, significant results were also found for the c-DRTT only (pmodel logistic = 0.035, ptract logistic = 0,044; plinear = 0.027).ConclusionsWe found a significant correlation between the distance of the DBS electrode pole to the c-DRTT and the clinical efficacy regarding tremor reduction. The c-DRTT might therefore play a major role in the mechanisms of alleviation of Parkinsonian tremor and could eventually serve as a possible DBS target for tremor-dominant PD in future.

Asymmetric Schottky Barrier in Rubrene Transistor via Monolayer Graphene Insertion toward Self-Powered Imaging

Organic semiconductor materials featuring lightweight, and flexibility may play a significant role in various future applications, such as foldable displays, wearable devices, and artificial skin. For developing high-performance organic devices, organic crystals are highly desired, while a remaining fundamental issue is their contact problem. Here, we have grown a high-quality rubrene single crystal by utilizing a simple in-air sublimation technique. The contact characteristics (barrier height and contact resistance) are detail-studied by resist-free transfer electrodes (Au metal or graphene/Au). The Schottky barrier of the rubrene/graphene interface is lower and can be also modulated by gate bias, which is confirmed by spatial photocurrent mapping. Finally, we demonstrated the zero-bias photocurrent imaging application by constructing the asymmetrical device employing different electrode contacts. Our work would be of significance for studying the contact issue of organic crystals and wireless imaging.

Electrochemical Pixels: Semi-open electrochemical cells with a vertically stacked design

A novel electrochemical cell design in a vertically stacked configuration is presented. Through a layered structure using a top macroporous working electrode, a polyelectrolyte, and a bottom metallic conductor a standalone electrochemical cell with an internal reference electrode is built. This sensor allows monitoring an electrochemical property of an external solution with only one electrode in direct contact with the sample. Using paper-based platinum electrode for the porous top electrode and Nafion as polyelectrolyte material, the self-powered detection of hydrogen peroxide is performed. The system can be operated in multiple modes. In a capacitive way, the open circuit potential is measured. Alternatively, in a self-powered current mode, the system emulates a fuel cell. Additionally, a potential-current switched mode is also demonstrated. Because of this unique design and operational features this sensor is considered as an electrochemical pixel. To further demonstrate the advantages of this device, the detection of glucose is performed by building an array of sensors using a single back (reference) electrode and multiple working electrodes. These results lay the groundwork for the development of a new generation of simple and low cost biochemical sensors and electrochemical sensing arrays.

Diffusion spectrum imaging based semi-automatic optic radiation tractography for vision preservation in SEEG-guided radiofrequency thermocoagulation

ObjectiveTo assess the efficacy and safety of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RFTC), using diffusion spectrum imaging (DSI) tractography to preoperatively delineate the optic radiation (OR) and reduce the risk of visual field defects (VFDs) where the epileptogenic zones (EZs) are located in or close to the eloquent visual areas. MethodsWe prospectively followed up twenty-four consecutive patients (12 males and 12 females) who underwent SEEG-guided RFTC in or near the OR pathway. A distance of ≥ 3.5 mm away from the OR on the targeted electrodes contacts that exhibited relevant ictal onset patterns, IEDs and EES during SEEG recordings, was required as our selection criterion prior to performing RFTC, enough to theoretically prevent VFDs. Using default tracking parameters, the optic radiation was tracked semi-automatically in DSI-studio. ResultsThere were 12 male and 12 female patients ranging in age from 6 to 57 years, with follow-up period ranging from 6 to 37 months. Nineteen patients responded to RFTC (R+, 79.16 %), and 5 patients did not benefit from RFTC (R-, 20.83 %). The preoperative application of DSI semi-automatic based OR tractography was successful in the protection of the OR in all 24 patients. Three patients experienced a neurologic deficit following RFTC, and five patients had a partial quadrant visual field deficit prior to surgery that did not worsen, and none of the remaining nineteen patients had a quadrant visual field deficit. ConclusionOur study validates the safety and efficacy of SEEG-RFTC as a viable therapeutic approach for epileptic foci situated in or adjacent to the visual eloquent regions. We demonstrate that DSI-based tractography offers superior precision in delineating the OR compared to DTI. We establish that implementing a criterion of a minimum distance of ≥ 3.5 mm in radius from the OR on the targeted electrode contacts prior to conducting RFTC can effectively mitigate the risk of VFDs.

Tailoring single-molecule conductance with structured graphene electrodes

Modulation of electric currents through single-molecule junctions is usually achieved by synthesis of molecules with desired functionalities, in conjunction with suitable molecule–electrode contacts through specific anchoring groups. An alternative to this approach, barely explored so far, is to use structured electrodes, where conductivity could eventually be controlled by changing the specific anchoring site within the very same electrode. Here, we theoretically investigate how to exploit the pronounced anisotropy of corrugated graphene deposited on Ru(0001) (Gr/Ru) to tailor single-molecule conductivity in 4-aminophenyl and 4-aminobenzonitrile. We show that currents induced in the upper and lower anchoring positions in the Gr/Ru moiré are substantially different, irrespective of the chosen molecule. The magnitude of these currents can differ by as much as an order of magnitude at specific bias voltages. We also show that both molecules display rectifying properties, which can differ by up to a factor of five in different anchoring sites. Interestingly, the observed modulations strongly depend on the chemical binding nature between the molecule and the electrode, (strong) covalent bond for 4-aminophenyl and (weak) physisorption for 4-aminobenzonitrile. All this suggests that Gr/Ru can be an ideal electrode to modulate single-molecule electric conductivity under experimental conditions that are available in many laboratories.

Interfacial energy barrier tuning in MnO2/MoS2/Carbon fabric integrated with low resistance textrode for highly efficient wearable thermoelectric generator

Wearable thermoelectric (TE), enabling direct conversion of human body heat into electricity have become the most promising alternative for conventional batteries on the Internet of Things based wearable electronic devices. The prime challenge in fabricating a high-performance wearable thermoelectric material is to combine the non-toxicity with high mechanical flexibility, excellent electrical conductivity and high Seebeck coefficient. This paper proposes a facile approach to fabricate a textile-based wearable thermoelectric generator (WTEG) with outstanding TE properties and exceptional flexibility. Herein, molybdenum disulphide (MoS2) nanosheets were grown on conductive carbon fabric (CF) via in-situ binder-free hydrothermal technique and manganese dioxide (MnO2) nanorods were decorated on it via dip coating, to form a 1D/2D interface. We investigated the in-plane TE properties of MnO2/MoS2/CF and achieved a superior power factor of 548.7 nW/mK2 which is 49.5 % higher than that of the pristine MoS2/CF. Such behaviour can be explained by the selective transmission of high energy carriers at the optimized MnO2/MoS2 interface. Moreover, this study is the first to employ a textile-based contact electrode in fabrication of WTEG that resulted in ultra-low internal resistance of the fabricated device (30–300 Ω). The lack of rigid contact electrodes leaves more flexibility, which benefits in enhanced wearability of the device. Owing to minimal internal resistance (29.4 Ω), the WTEG comprising of 1 -n/p pair could produce an open circuit voltage, as high as 0.2 mV under the thermal gradient of 15–20 K. Additionally, we demonstrated that increasing the number of modules from 1 pair to 4 pairs systematically improved the device performance. The open circuit voltage and output power generated for WTEG comprising of 4 -n/p pairs is measured to be 1.2 mV and 1 nW, respectively. This work provides a feasible design solution for a low resistance, rigid-free WTEGs with high performance which can significantly support the growth of research in wearable thermoelectrics.

A study on defect, doping, and performance of ETLs (ZnO, TiO2, and IGZO) for the lead-free CsSnCl3 perovskite solar cell by SCAPS-1D framework

The potential of lead-free perovskite materials using cesium as an organic cation has been explored as a replacement for lead-based perovskite absorbers to minimize toxicity. These materials exhibit high stability, a tunable bandgap, and superior optoelectronic properties compared to lead-based materials. Extensive studies have investigated Sn-based cesium tin chloride (CsSnCl3) in the literature, focusing on multiple hole transporting layers (HTLs) and electron transporting layers (ETLs). A numerical study has been conducted to study the effects of thickness, series, and shunt resistance, as well as favorable band alignment with the absorber, HTL, and ETL layers. According to the literature, ETLs such as TiO2, ZnO, and IGZO, in combination with CBTS as the HTL, have emerged as the most promising candidates for achieving optimal fabrication of CsSbCl3 devices. However, several investigations have yet to be covered in the reports. These include analyzing the effects of absorber and interface defects on the ETLs/HTLs layers, determining the optimal metal back contact electrode, and optimizing the doping concentration of the absorber or ETLs/HTLs to achieve device optimization and the desired operating temperature. Through the optimization process, the study identified the optimum numerical values necessary to achieve higher device performance. It specifically found that ZnO performs the best as an ETL candidate, and the configuration combination of ITO/ZnO/(CsSnCI3)/CBTS/Se emerged as the most favorable compared to the values reported in the literature.

Impedance spectroscopy analysis on reduced graphene oxide and CeO2 nanocomposites coated on screen-printed alumina substrate for highly selective H2S gas detection at room temperature

Impedance spectroscopic-based gas sensing analysis is a highly sensitive technique. Impedance and its fitted RC circuits provide us with fundamental information about grain boundary, grain bulk, and the interface between sensing film and electrode contact. In this work, an n-CeO2/rGO composite-based gas sensing film with high selectivity, sensitivity, stability and moisture resistance potency for the detection of H2S was developed on screen-printed alumina substrate using a drop casting process, and the H2S gas sensing performance was evaluated using electrochemical impedance spectroscopy (EIS) at various temperatures. The n-CeO2/rGO-3 composite produced stable and rapid responses towards H2S with a response of 97.41 % for 50 ppm of H2S gas at the optimum temperature of room temperature (27 °C). The LOD and LOQ were calculated and found to be ∼0.9 and ∼2.9 ppm for n-CeO2 and n-CeO2/rGO-3 composites, respectively. The superior selectivity with interfering gases such as NH3, H2, SO2 and CO, response and recovery time (∼9s and ∼12s), long-time stability and gas sensing mechanism were investigated. This impedance-based gas sensor development opens up the path for the fabrication of n-CeO2/rGO composite-based H2S gas sensors for future applications.

Combining ultrasound and microelectrode recordings for postoperative localization of subthalamic electrodes in Parkinson’s disease

ObjectiveTo assess transcranial sonography (TCS) as stand-alone tool and in combination with microelectrode recordings (MER) as a method for the postoperative localization of deep brain stimulation (DBS) electrodes in the subthalamic nucleus (STN). MethodsIndividual dorsal and ventral boundaries of STN (n = 12) were determined on intraoperative MER. Postoperatively, a standardized TCS protocol was applied to measure medio-lateral, anterior-posterior and rostro-caudal electrode position using visualized reference structures (midline, substantia nigra). TCS and combined TCS-MER data were validated using fusion-imaging and clinical outcome data. ResultsTest-retest reliability of standard TCS measures of electrode position was excellent. Computed tomography and TCS measures of distance between distal electrode contact and midline agreed well (Pearson correlation; r = 0.86; p < 0.001). Comparing our “gold standard” of rostro-caudal electrode localization relative to STN boundaries, i.e. combining MRI-based stereotaxy and MER data, with the combination of TCS and MER data, the measures differed by 0.32 ± 0.87 (range, −1.35 to 1.25) mm. Combined TCS-MER data identified the clinically preferred electrode contacts for STN-DBS with high accuracy (Coheńs kappa, 0.86). ConclusionsCombined TCS-MER data allow for exact localization of STN-DBS electrodes. SignificanceOur method provides a new option for monitoring of STN-DBS electrode location and guidance of DBS programming in Parkinson’s disease.

Direct transformation of polycarbonate to highly conductive and superhydrophobic graphene/graphitic composite by laser writing and its applications

Polycarbonate (PC) is widely used as an important engineering polymer in numerous applications and diverse fields, ranging from optical components to building construction. Three-dimensional (3D) graphene-based material has growing interest owing to its excellent properties, impacting research fields in energy storage, biomedical, environmental applications, and more. Although laser treatment-based generation of graphene and graphitization has been demonstrated in various polymers, they have not so far been shown in PC. Here, we report that under the right conditions, industrially important material such as PC can also transformed into graphene and its properties are quite distinct from graphene generated in other organic polymers such as polyimide (PI). A 3D porous hierarchical graphene/graphitic composite structure is formed in PC due to laser treatment and it exhibited the highest electrical conductivity with a sheet resistance down to 0.8 Ω sq−1 among all the laser induced graphitic (LIG) material generated using laser treatment. The unique hierarchical structure in the 3D graphene layer produces a robust and durable superhydrophobicity (contact angle at 170.6° ± 8.8°) in the ambient environment. We demonstrate integration of gold nanoparticles into the graphene layer using the same single step laser treatment for its application as a glucose sensor, and also demonstrate its other applications for direct integration of contact electrode of a chemiresistive sensor, a temperature sensor, and as an electrical heater on insulating materials. Since PC is such an important and widely used industrial plastic, these integration methods are of broad applicability to instrument components made of PC directly.

Seeing Is Believing: Photon Counting Computed Tomography Clearly Images Directional Deep Brain Stimulation Lead Segments and Markers After Implantation

Background and ObjectivesDirectional deep brain stimulation (DBS) electrodes are increasingly used, but conventional computed tomography (CT) is unable to directly image segmented contacts owing to physics-based resolution constraints. Postoperative electrode segment orientation assessment is necessary because of the possibility of significant deviation during or immediately after insertion. Photon-counting detector (PCD) CT is a relatively novel technology that enables high resolution imaging while addressing several limitations intrinsic to CT. We show how PCD CT can enable clear in vivo imaging of DBS electrodes, including segmented contacts and markers for all major lead manufacturers. Materials and MethodsWe describe postoperative imaging and reconstruction protocols we have developed to enable optimal lead visualization. PCD CT images were obtained of directional leads from the three major manufacturers and fused with preoperative 3T magnetic resonance imaging (MRI). Radiation dosimetry also was evaluated and compared with conventional imaging controls. Orientation estimates from directly imaged leads were compared with validated software-based reconstructions (derived from standard CT imaging artifact analysis) to quantify congruence in alignment and directional orientation. ResultsHigh-fidelity images were obtained for 15 patients, clearly indicating the segmented contacts and directional markers both on CT alone and when fused to MRI. Our routine imaging protocol is described. Ionizing radiation doses were significantly lower than with conventional CT. For most leads, the directly imaged lead orientations and depths corresponded closely to those predicted by CT artifact-based reconstructions. However, unlike direct imaging, the software reconstructions were susceptible to 180° error in orientation assessment. ConclusionsHigh-resolution photon-counting CT can very clearly image segmented DBS electrode contacts and directional markers and unambiguously determine lead orientation, with lower radiation than in conventional imaging. This obviates the need for further imaging and may facilitate anatomically tailored directional programming.

Improving efficiency of [formula omitted] CoSn [formula omitted] solar cells using an HTL layer: A numerical study

In recent years, the material copper cobalt tin sulfur Cu2 CoSn S4 (CCTS) has attracted a lot of attention in photovoltaic applications because of its gap energy close to 1.5 eV. However, the efficiency of CCTS-based solar cells is still low. In our study, we presented a numerical study of a CCTS-based solar cell with a Mo/CCTS/ZnS/ITO structure using the SCAPS-1D simulator. Each layer of our solar cell was optimized separately, and the effect of the back contact electrode was also studied. We obtained the best performance using Pt as the back contact electrode. However, to reduce production costs, we used Mo as the back contact electrode, which caused a problem with the appearance of a Schottky barrier between Mo and CCTS. To solve this problem, we used an HTL layer between CCTS and Mo, which improved the efficiency of our cell from 24 % to 32 %. Also, in our work, we evaluate the effect of parasitic resistances (Rs, Rsh) and temperature on the performance of our solar cell.

Bilateral intracochlear schwannomas: histopathological confirmation and outcomes following tumour removal and cochlear implantation with lateral wall electrodes.

Intracochlear schwannomas (ICS) are very rare benign tumours of the inner ear. We present histopathological proof of the extremely rare bilateral occurrence of intracochlear schwannomas with negative blood genetic testing for neurofibromatosis type2 (NF2). Bilateral schwannomas are typically associated with the condition NF2 and this case is presumed to have either mosaicism for NF2 or sporadic development of bilateral tumours. For progressive bilateral tumour growth and associated profound hearing loss, surgical intervention via partial cochleoectomy, tumour removal, preservation of the modiolus, and simultaneous cochlear implantation with lateral wall electrode carrier with basal double electrode contacts was performed. The right side was operated on first with a14-month gap between each side. The hearing in aided speech recognition for consonant-nucleus-consonant (CNC) phonemes in quiet improved from 57% to 83% 12months after bilateral cochlear implantation (CI). Bilateral intracochlear schwannomas in non-NF2 patients are extremely rare but should be considered in cases of progressive bilateral hearing loss. Successful tumour removal and cochlear implantation utilizing alateral wall electrode is possible and can achieve good hearing outcomes.

Electrical and Thermal Conductivities of Single CuxO Nanowires.

Copper oxide nanowires (NWs) are promising elements for the realization of a wide range of devices for low-power electronics, gas sensors, and energy storage applications, due to their high aspect ratio, low environmental impact, and cost-effective manufacturing. Here, we report on the electrical and thermal properties of copper oxide NWs synthetized through thermal growth directly on copper foil. Structural characterization revealed that the growth process resulted in the formation of vertically aligned NWs on the Cu growth substrate, while the investigation of chemical composition revealed that the NWs were composed of CuO rather than Cu2O. The electrical characterization of single-NW-based devices, in which single NWs were contacted by Cu electrodes, revealed that the NWs were characterized by a conductivity of 7.6 × 10-2 S∙cm-1. The effect of the metal-insulator interface at the NW-electrode contact was analyzed by comparing characterizations in two-terminal and four-terminal configurations. The effective thermal conductivity of single CuO NWs placed on a substrate was measured using Scanning Thermal Microscopy (SThM), providing a value of 2.6 W∙m-1∙K-1, and using a simple Finite Difference model, an estimate for the thermal conductivity of the nanowire itself was obtained as 3.1 W∙m-1∙K-1. By shedding new light on the electrical and thermal properties of single CuO NWs, these results can be exploited for the rational design of a wide range of optoelectronic devices based on NWs.

Controlled synthesis of van der Waals CoS2 for improved p-type transistor contact

Two-dimensional (2D) van der Waals (vdW) p-type semiconductors have shown attractive application prospects as atomically thin channels in electronic devices. However, the high Schottky hole barrier of p-type semiconductor–metal contacts induced by Fermi-level pinning is hardly removed. Herein, we prepare a vdW 1T-CoS2 nanosheet as the contact electrode of a WSe2 field-effect transistor (FET), which shows a considerably high on/off ratio > 107 and a hole mobility of ∼114.5 cm2 V−1 s−1. The CoS2 nanosheets exhibit metallic conductivity with thickness dependence, which surpasses most 2D transition metal dichalcogenide metals or semimetals. The excellent FET performance of the CoS2-contacted WSe2 FET device can be attributed to the high work function of CoS2, which lowers the Schottky hole barrier. Our work provides an effective method for growing vdW CoS2 and opens up more possibilities for the application of 2D p-type semiconductors in electronic devices.

Two-dimensional single-substance phosphor photodetectors: A device mechanism study based on van der Waals electrode contacts

Two-dimensional single-substance phosphor photodetectors: A device mechanism study based on van der Waals electrode contacts