Multidipping Technique for Fabrication Time Reduction and Performance Improvement of Solution-Processed Single-Walled Carbon Nanotube Thin-Film Transistors

Herein, a simple and effective technique, "multidipping technique," is implemented to rapidly form random networks of single-walled carbon nanotubes (SWCNTs) used as a channel material in solution-processed thin-film transistors (TFTs). The multidipping process consists of repetition of dipping a substrate into a dispersed semiconducting SWCNT solution and rinsing the substrate between each dipping process. Compared with the conventional dipping method, this technique reduces total deposition time required to form high-quality SWCNT networks by more than half and simultaneously improves the electrical performances of SWCNT TFTs. These phenomena are also comprehensively analyzed with experiments and microscopic images of the channel region, which well show morphology of the SWCNT networks. It is believed that the low-temperature process and facile deposition method of SWCNT networks can provide a guideline for high-throughput fabrication of high-performance SWCNT TFT arrays in flexible active matrix sensor array and display applications.N

The Association between Excessive Internet Gaming Behavior and Immersive Tendency, Mediated by Attention Deficit/Hyperactivity Disorder Symptoms, in Korean Male University Students

Objective Problematic online gaming (POG) and problematic Internet use (PIU) have become a serious public mental health problem, with Internet gaming disorder (IGD) included in "Conditions for further study" section of DSM-5. Although higher immersive tendency is observed in people affected by POG, little is known about the simultaneous effect of immersive tendency and its highly comorbid mental disorder, attention deficit/hyperactivity disorder (ADHD). This study aimed to assess the relationship between immersive tendency, ADHD, and IGD. Methods Cross-sectional interview study was conducted in Seoul, Korea with 51 male undergraduate students; 23 active garners and 28 controls. Results Current ADHD symptoms showed partial mediation effect on the path of immersive tendency on POG and PIU. The mediation model with inattention explained variance in both POG and PIU better than other current ADHD symptom models (R-2=69.2 in POG; 69.3 in PIU). Childhood ADHD symptoms models demonstrated mediation effect on both POG and PIU which explained less variance than current ADHD symptom models (R-2 =53.7 in POG; 52.1 in PIU). Current ADHD symptoms, especially inattention, appear to mediate the effect of immersive tendency on POG/PIU. Conclusion Immersive tendencies may entail greater susceptibility to IGD, and comorbidity with ADHD may mediate the effect of immersive tendency on IGD

Feasibility Study of the Paper Sludge Properties in Manufacturing Recycled Filler

The mineralization of inorganic components in paper sludge offers potential for their re-use in various fields. This study synthesized carbonates based on the minerals present in paper sludge and aimed to investigate the control of particle size distribution and particle shape of the synthesized carbonates. First, the physicochemical and thermal properties of paper mill sludge and ash were evaluated using a spectrophotometer, XRF, and TGA. Paper sludge ash was obtained by incinerating the paper sludge, followed by a carbonation reaction using CO2 gas injection and pH neutralization to produce recycled fillers. The average particle size, crystal lattice structure, and morphology of the recycled fillers were analyzed using a particle size analyzer, XRD, and FE-SEM. The results indicate that the recycled filler produced from coating paper sludge exhibited similar brightness and morphology to conventional paper-based fillers, suggesting its potential to replace commercial PCC (Precipitated Calcium Carbonate). In contrast, the recycled filler manufactured using old corrugated container mill sludge was deemed unsuitable due to its low hydration activity

Multidipping Technique for Fabrication Time Reduction and Performance Improvement of Solution‐Processed Single‐Walled Carbon Nanotube Thin‐Film Transistors

Herein, a simple and effective technique, "multidipping technique," is implemented to rapidly form random networks of single-walled carbon nanotubes (SWCNTs) used as a channel material in solution-processed thin-film transistors (TFTs). The multidipping process consists of repetition of dipping a substrate into a dispersed semiconducting SWCNT solution and rinsing the substrate between each dipping process. Compared with the conventional dipping method, this technique reduces total deposition time required to form high-quality SWCNT networks by more than half and simultaneously improves the electrical performances of SWCNT TFTs. These phenomena are also comprehensively analyzed with experiments and microscopic images of the channel region, which well show morphology of the SWCNT networks. It is believed that the low-temperature process and facile deposition method of SWCNT networks can provide a guideline for high-throughput fabrication of high-performance SWCNT TFT arrays in flexible active matrix sensor array and display applications.N

Fluoroelastomer encapsulation for enhanced reliability of solution-processed carbon nanotube thin-film transistors

Single-walled carbon nanotube (SWCNT) has attracted considerable attention as a promising semiconducting material due to its high field-effect mobility, high current-carrying capability, and superior mechanical durability. However, SWCNT-based thin-film transistors (SWCNT-TFTs) generally show insufficient electrical reliability in terms of the drain-current hysteresis and threshold voltage shift under the bias stress. To facilitate the great advantages of SWCNT in commercial electronic devices, strategies are required for enhancing the electrical reliability of SWCNT-TFTs without compromising their mechanical flexibility. In this work, we demonstrate solution-processed, hysteresis-free, and bias-stable SWCNT-TFTs encapsulated with elastomeric poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVDF-HFP) using a lamination method. The dipolar nature of e-PVDF-HFP suppresses the charge trapping, resulting in elimination of hysteresis as well as enhancement of field-effect mobility and subthreshold slope. The bias instability under the negative gate bias stress is also alleviated because the hydrophobic encapsulation layer can exclude physisorbed water/oxygen molecules on the hydrophilic surface. Besides, our solvent-free lamination method effectively prevents the potential damages of the active and electrode layers from the use of the solvents. The proposed encapsulation method with laminating the e-PVDF-HFP film can provide a possibility for realization of wearable applications based on highly reliable solution-processed SWCNT-TFT.N

Dense Assembly of Finely Patterned Semiconducting Single-Walled Carbon Nanotubes via a Selective Transfer Method of Nanotube-Attracting Layers

Development of technology for assembled single-walled carbon nanotube (SWCNT) film with the fine resolution is an essential technique for penetrating practical electronic applications. A promising approach is the assembly method by adding a chemical-functionalizing substrate to enhance affinity between the SWCNTs and the substrate. However, the various introduced approaches for solution-based assembly have suffered from low SWCNT deposition selectivity or low SWCNT deposition density. Herein, we demonstrated a facile method for selectively assembling semiconducting SWCNT network on the substrate. The substrate was prepared via a transfer printing of a poly-L-lysine (PLL)-coated poly(dimethylsiloxane) (PDMS) stamp. The thermal-assisted transfer method enabled an ultrafine PLL pattern (<= 4 mu m) and a high transfer yield (96.5%) by only one-time stamping without a change of the SWCNT-attracting nature. So, semiconducting SWCNTs were deposited on the patterned regions selectively and precisely. The benefit of the patterned semiconducting SWCNTs was lowering leakage current and turn-on voltage in the transfer characteristics by suppressing attachment of unnecessary SWCNT network. They showed excellent electrical performance, a log(10) (I-on/I-off) ratio of 4.76, and an average value of linear field-effect mobility of 7.56 cm(2)/(V s). This research provides a simple but high-quality assembling technique of semiconducting SWCNTs, thereby improving the feasibility of solution-processed SWCNT-TFTs.N

Tunable Stability of All-Inkjet-Printed Double-Gate Carbon Nanotube Thin Film Transistors

In this letter, we improved the stability of all-inkjet-printed carbon nanotube thin film transistors (CNT TFTs) by employing a double gate (DG) structure under an optimal bias condition. In the single-gate structure, the positive threshold voltage (VTH) shift under 10 V positive gate bias stress (PGBS) was significantly reduced with poly(4-vinylphenol) passivation. However, after 100 s, the on-current level was decreased, and a large negative VTH shift was observed. We adopted DG CNT TFTs for a further improvement. When-3V was applied to the top gate, the DG CNT TFTs not only exhibited a much lower VTH shift but also showed a stabilized on-current level. When an appropriate bias is applied to the top gate, charge trapping is induced at the top gate interface and it might balance between the positive and negative shifts. As a result, the overall stress effect is reduced. The p-type only inverter adopting a DG CNT TFT showed improved stability under -3 V of top gate bias. Our experimental result shows that DG structure is a promising candidate for various CNT circuit designs.N