This work investigated the elimination of Methyl Orange (MO) using a new adsorbent prepared from Activated Carbon (AC) with polyaniline reinforced by a simple oxidation chemical method. The prepared materials were characterized using XRD, TGA, FTIR and nitrogen adsorption isotherms. Furthermore, PANI@CA highest specific surface area values (near 332 m2 g−1) and total mesoporous volume (near 0.038 cm3 g−1) displayed the better MO removal capacity (192.52 mg g−1 at 298 K and pH 6.0), which is outstandingly higher than that of PANI (46.82 mg g−1). Besides, the process’s adsorption, kinetics, and isothermal analysis were examined using various variables such as pH, MO concentration and contact time. To pretend the adsorption kinetics, various kinetics models, the pseudo first- and pseudo second- orders, were exercised to the experimental results. The kinetic analysis revealed that the pseudo second order rate law performed better than the pseudo first order rate law in promoting the formation of the chemisorption phase. In the case of isothermal studies, an analysis of measured correlation coefficient (R2) values showed that the Langmuir model was a better match to experimental results than the Freundlich model. By regeneration experiments after five cycles, acceptable results were observed.

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Anionic Methyl Orange Removal from Aqueous Solutions by Activated Carbon Reinforced Conducting Polyaniline as Adsorbent: Synthesis, Characterization, Adsorption Behavior, Regeneration and Kinetics Study

Transparent conductive films (TCFs) are irreplaceable components in most optoelectronic applications such as solar cells, organic light‐emitting diodes, sensors, smart windows, and bioelectronics. The shortcomings of existing traditional transparent conductors demand the development of new material systems that are both transparent and electrically conductive, with variable functionality to meet the requirements of new generation optoelectronic devices. In this respect, TCFs with periodic or irregular nanomesh structures have recently emerged as promising candidates, which possess superior mechanical properties in comparison with conventional metal oxide TCFs. Among the methods for nanomesh TCFs fabrication, nanosphere lithography (NSL) has proven to be a versatile platform, with which a wide range of morphologically distinct nanomesh TCFs have been demonstrated. These materials are not only functionally diverse, but also have advantages in terms of device compatibility. This review provides a comprehensive description of the NSL process and its most relevant derivatives to fabricate nanomesh TCFs. The structure‐property relationships of these materials are elaborated and an overview of their application in different technologies across disciplines related to optoelectronics is given. It is concluded with a perspective on current shortcomings and future directions to further advance the field.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/adma.202103842

Nanosphere Lithography: A Versatile Approach to Develop Transparent Conductive Films for Optoelectronic Applications

The construction of fibrous ionic conductors and sensors with large stretchability, low-temperature tolerance, and environmental stability is highly desired for practical wearable devices yet is challenging. Herein, metallogels (MOGs) with a rapidly reversible force-stimulated sol-gel transition were employed and encapsulated into a hollow thermoplastic elastomer (TPE) microfiber through a simple coaxial spinning. The resultant MOG@TPE coaxial fiber exhibited a high stretchability (>100%) in a broad temperature range (-50 to 50 °C). The MOG@TPE fibrous strain sensor demonstrated a high-yet-linear working curve, fast response time (<100 ms), highly stable conductivity under large deformation, and excellent cycling stability (>3000 cycles). The MOG@TPE fibrous sensors were demonstrated to be directly attached to the human skin to monitor the real-time movements of large/facet joints of the elbow, wrist, finger, and knee. It is believed that the present work for preparing the stretchable ionic conductive fibers holds great promise for applications in fibrous wearable sensors with broad temperature range, large stretchability, stable conductivity, and high wearing comfort.

Stretchable, Environment-Stable, and Knittable Ionic Conducting Fibers Based on Metallogels for Wearable Wide-Range and Durable Strain Sensors.

A series of polyimides (PIs) containing a bulky side group of m-trifluoromethyl phenyl was synthesized via a high-temperature one-step polycondensation of 4-[3′,5′-bis(trifluoromethyl)phenyl]-1,3-phenylenediamine (2) and various aromatic dianhydrides. The weight-averaged molecular weights (Mw) of the resulting PIs are between 3.92 and 8.36 × 104 g mol−1 with the Mw/Mn of 1.77–2.09. They are soluble in common organic solvents and easily processed into flexible films by the blade coating of PI solution. At room temperature, the dielectric constants (k) of these PI films are lower than 3.04 at 1 MHz and 2.87 at 10 GHz, especially the k of 2-6FDA film is low to 2.66 at 1 MHz and 2.38 at 10 GHz. The breakdown strength of the resulting PI films (thickness: 10 ± 1 μm) is in the range from 461 to 523 kV mm−1. Meanwhile, these PI films also show good thermal stability (5 wt% weight-loss temperature in the range of 521–571 °C under N2; glass transition temperatures of 266–307 °C) and mechanical properties (tensile strength of 70.8–103.3 MPa, tensile modulus of 1.3–2.2 GPa, elongation at break of 9.1–10.8%). The average transmittance of these PI films (around 20 μm) is above 80% in the visible light region (400–760 nm). Such attractive comprehensive properties make these PIs as potential candidates for application in microelectronics industry.

Organosoluble polyimides with low dielectric constant prepared from an asymmetric diamine containing bulky m-trifluoromethyl phenyl group

Four kinds of polyimide (PI) films were prepared by polycondensation reaction using the pyromellitic dianhydride (PMDA) and 4, 4′-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA）as the dianhydride monomer, the p-phenylenediamine (PDA), 4-4′-diaminodiphenyl ether (ODA) and 4,4′-(Hexafluoroisopropylidene) bis(p-phenyleneoxy) dianiline (HFBDA) as the diamine monomer respectively. The incorporation of trifluoromethyl groups can effectively inhibit the formation of intermolecular and intramolecular charge-transfer complex (CTC), improve the energy gap and increase the free volume in PI, which leads to an improvement in the optical and dielectric properties in different degree for three fluorinated PI films compared with the Kapton film. The maximum transmittance in visible region reaches 90.5% and the dielectric constant at 104Hz is close to 2.0 for PI6FDA-HFPBDA film. The breakdown strength weakens because of the increase of free volume. The correlation between the dielectric and breakdown characteristics and their free volume has been explained with the help of positron lifetime spectra. 

Characterization of intrinsic low-polyimide films studied by positron annihilation

Conductive polymers are considered promising electrode materials for organic transistors, but the reported devices with conductive polymer electrodes generally suffer from considerable contact resistance. Currently, it is still highly challenging to pattern conductive polymer electrodes on organic semiconductor surfaces with good structure and interface quality. Herein, we develop an in situ polymerization strategy to directly pattern the top-contacted polypyrrole (PPy) electrodes on hydrophobic surfaces of organic semiconductors by microchannel templates, which is also applicable on diverse hydrophobic and hydrophilic surfaces. Remarkably, a width-normalized contact resistance as low as 1.01 kΩ·cm is achieved in the PPy-contacted transistors. Both p-type and n-type organic field-effect transistors (OFETs) exhibit ideal electrical characteristics, including almost hysteresis-free, low threshold voltage, and good stability under long-term test. The facile patterning method and high device performance indicate that the in situ polymerization strategy in confined microchannels has application prospects in all-organic, transparent, and flexible electronics.

Directly Patterning Conductive Polymer Electrodes on Organic Semiconductor via In Situ Polymerization in Microchannels for High-Performance Organic Transistors.

Nanospheres lithography (NSL) is an economical technique, which makes use of highly monodispersed nanospheres such as deposition or etch masks for generating patterns with nanoscale features. Embedding nanostructures into organic electronic devices can endow them with unique capabilities and enhanced performance, which have greatly advanced the development of organic electronics. In this review, a brief summary of the methods for the preparation of monodispersed nanospheres is presented. Afterward, the authors highlight the recent advances of a wide variety of applications of nanospheres lithography in organic electronic devices. Finally, the challenges in this field are pointed out, and the future development of this field is discussed.

Recent Advances of Nanospheres Lithography in Organic Electronics

Functionalization of Low‐k Polyimide Gate Dielectrics with Self‐Assembly Monolayer Toward High‐Performance Organic Field‐Effect Transistors and Circuits

Simultaneous and distinguishable detection of external stimuli such as light and temperature is of great interest for a variety of scientific and industrial applications. Theoretically, an organic semiconductor with low exciton binding energy, low thermal activation energy and good charge transporting property produces thermally enhanced photo-electric response in organic phototransistors (OPTs), which thus provides an ideal and effective way to realize the simultaneous and distinguishable detection of temperature and light. However, there is no report on such kind of organic semiconductor until now. Herein, we designed and synthesized a narrow band gap organic small molecule semiconductor 2,5-bis(2-butyloctyl)-3,6-bis(5-(4-(diphenylamino)phenyl)thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP-T-TPA) with low exciton binding energy (about 37 meV) and small activation energy (about 61 meV) for distinct thermal-dependence of charge carrier and exciton. The low exciton binding energy enables the semiconductor to exhibit strong thermal dependence of exciton dissociation, which contributes to the thermally-enhanced photo-electric response. Furthermore, the low thermal activation energy produces the weak thermal dependence of charge transport, which avoids the disturbance of thermally-modulated charge transport on photo-electric response. Benefiting from these two features, phototransistors based on DPP-T-TPA show great potential in simultaneous and distinguishable detection of light and temperature, which represents a novel and efficient way for bifunctional detection.

Thermally-enhanced photo-electric response of an organic semiconductor with low exciton binding energy for simultaneous and distinguishable detection of light and temperature

Li Yu

Papers

Directly Patterning Conductive Polymer Electrodes on Organic Semiconductor via In Situ Polymerization in Microchannels for High-Performance Organic Transistors.

Recent Advances of Nanospheres Lithography in Organic Electronics

Functionalization of Low‐k Polyimide Gate Dielectrics with Self‐Assembly Monolayer Toward High‐Performance Organic Field‐Effect Transistors and Circuits

Thermally-enhanced photo-electric response of an organic semiconductor with low exciton binding energy for simultaneous and distinguishable detection of light and temperature