Unveiling the Potential of Covalent Organic Framework Electrocatalyst for Enhanced Oxygen Evolution.

The potential for sustainable energy and carbon neutrality has expanded with the development of a highly active electrocatalyst for the oxygen evolution reaction (OER). Covalent Organic Frameworks (COF) have recently garnered attention because of their enormous potential in a number of cutting-edge application sectors, such as gas storage, sensors, fuel cells, and active catalytic supports. A simple and effective COF constructed and integrated by post-alteration plasma modification facilitates high electrocatalytic OER activity under alkaline conditions. Variations in parameters such as voltage and treatment duration have been employed to enhance the factor that demonstrates high OER performance. The overpotential and Tafel slope are the lowest of all when using an optimized parameter, such as plasma treatment for 30 min utilizing 6 kV of voltage, PT-30 COF, measuring 390 mV at a current density of 10 mA.cm-2 and 69 mV.dec-1, respectively, as compared to 652 mV and 235 mV.dec-1 for the Pristine-COF. Our findings provide a method for broadening the scope by post-functionalizing the parent framework for effective water splitting.

Assessing CO2 Adsorption Behavior onto Free-Standing, Flexible Organic Framework-PVDF Composite Membrane: An Empirical Modeling and Validation of an Experimental Data Set.

Covalent organic framework (COF) materials have greatly expanded their range in a variety of applications since the cognitive goal of a highly organized and durable adsorbent is quite rational. The characteristics of a conjugated organic framework are combined with an industrially relevant polymer to produce a composite membrane optimized for selectively adsorbing carbon dioxide (CO2) gas across a wide temperature range. Additionally, treatment of the composite membrane with cold atmospheric plasma (CAP) that specifically enhanced the parent membrane's surface area by 36% is established. Following CAP treatment, the membrane accelerates the CO2 uptake by as much as 66%. This is primarily due to a Lewis acid-base interaction between the electron-deficient carbon atom of CO2 and the newly acquired functionalities on the COFs@PVDF membrane's surface. In particular, the C-N bonds, which appear to be a higher electron density site, play a key role in this interaction. Moreover, the empirical model proposed here has confirmed CO2 adsorption phenomena in the COF@PVDF composite membrane, which closely matches the findings from the experimental data set under designated operating conditions. As a result, the current study may pave the way for future design work as well as refine the covalent framework polymer composite membrane's features, revealing a more sophisticated approach to addressing CO2 capture problems.

Enabling Ultrahigh Surface Area of Covalently-linked Organic Framework for Boosted CO2 Capture: An Air Liquid Interfacial Plasma as Post-furnishing Protocol.

The cognitive intent of a highly ordered and robust adsorbent is extremely sensible and, in this context, Covalent Organic Framework (COF) materials have significantly burgeoned their scope in diverse applications. Herein, a simple time-competent hydrothermal procedure is presented to construct a covalent framework with an ultrahigh surface area of 1428 m2 /g that shows active adsorption of carbon dioxide (CO2 ) at variable temperature ranges. Moreover, a facile scalably controlled post-synthetic air liquid interfacial plasma (ALIP) induced protocol is substantiated that explicitly amplifies the surface area of the pristine framework even to a higher value of 2051 m2 /g. The post-synthetic plasma approach presented here led to the rapid enhancement of the surface area of the pristine COF by 43 %, which concurrently advances the CO2 uptake up to 67 %. Hence, the current study may open up a new frontier in the design as well as fine-tune the properties of the covalent framework that unfolds the advanced outlook in addressing the challenges of CO2 capture.

Correction: Realization of multi-configurable logic gate behaviour on fluorescence switching signalling of naphthalene diimide congeners.

[This corrects the article DOI: 10.1039/D1RA06728A.].

Realization of multi-configurable logic gate behaviour on fluorescence switching signalling of naphthalene diimide congeners.

Organic entities like suitably functionalized naphthalene diimide (NDI) exhibited logical behaviours in response to various external stimuli and can be used to develop digital logic operations. The present findings include utilization of two congeners of NDI i.e., N1 and N2 for the successive turning ON/OFF of fluorescence with inclusion of acid and base. The recognition of the switching phenomenon of the probes N1 and N2 are applied to construct fundamental digital logic gates such as NOT, YES, IMPLICATION, INHIBIT, etc. The inputs to each of the logic gates are defined by the presence or absence of acid and base. Accordingly, the outputs generated from the gates are in the form of fluorescence ON or OFF status denoted by "1" and "0" respectively. Likewise, we have adopted Boolean algebra and its associated De-Morgan's theorem to build the combined logic gates such as XOR and XNOR gates. The proposed logic gates are validated by the optical behaviour of the congeners N1 and N2 in response to acid as well as base and the experimental results are confirmed by the theoretical predictions. The proposed work can have potential applications in next-generation logic based analytical applications.

Stimuli-Responsive Naphthalene Diimide as Invisible Ink: A Rewritable Fluorescent Platform for Anti-Counterfeiting.

Herein, we report an approach to combat counterfeiting and storage of valuable information based on the solid-state fluorescence switching behavior of isoniazid functionalized naphthalene diimide (ISO_NDI) in response to an external stimuli (i. e., HCl vapor). The unique feature of ISO_NDI is further utilized to develop an invisible ink (ISO_NDI-PVA) with commercial polymer polyvinyl alcohol (PVA). A solid-state fluorescence recovery was observed while loading with HCl vapors. This exclusive property of the material could be applied directly as a security ink for confidential data storage purpose. Based on above strategy, we successfully realized the rewritable application by using ISO_NDI-PVA ink and confirm its practical efficacy on various substrates by creating different patterns. The solid-state fluorescence switching behavior of ISO_NDI-PVA ink exhibited reversible on/off signal for multiple cycles under the influence of HCl/NH3 vapors. Mechanistic investigation supports a clear participation of intermolecular charge transfer (ICT) phenomenon in the solid-state fluorescence switching property. The ease of fabricating the ink with invisible to visible characteristics in response to HCl vapors provides new opportunities for exploring the application of ISO_NDI-PVA as invisible ink for targeted security applications.

Conjugated Polymer-Based Electrical Sensor for Ultratrace Vapor-Phase Detection of Nerve Agent Mimics.

Considering the vital need to strengthen the national security emanating from chemical threats, a low-cost, portable ultrasensitive electrical sensor for real-time monitoring of diethylchlorophosphate (DCP) (nerve gas mimic) has been developed. The device consists of a "simple to be fabricated" two-terminal resistor and an electronic combinational circuit for rapid onsite detection of lethal nerve gas vapors with high degree of accuracy in milliseconds. This device is a smart readout electronic model that detects ultratrace DCP vapors by bright visual alerts from light-emitting diode (LED) and loud alarm signal without the need for employing a sophisticated instrument. To obtain high sensitivity and discriminating response, a novel amine-functionalized conjugated polymer (CP) is designed as a sensory channel material for two-terminal sensor. The low-powered poly(3-(9,9-dioctyl-9H-fluoren-2-yl)benzene-1,2-diamine) (PFPDA) fabricated two-terminal electrical sensor is tested at ambient conditions, which shows excellent sensitivity toward nerve gas mimic DCP, with a rapid response in 3 s and a very low limit of detection (LOD) of 5.88 ppb. The amine moiety of PFPDA CP plays a vital role in redox interaction between the semiconductor CP and organophosphates, which ultimately leads to the amplified current signal. The redox interactions occurring among the organophosphate analytes and the amine functional group on the PFPDA backbone provided insights into the mechanism of sensing, which formed the basis of the excellent sensitivity and discriminating ability of this sensor device. The newly designed PFPDA CP-based portable electrical sensor device demonstrates a key contribution in the field of portable electronics for defense safety and environmental monitoring applications.

Synergistic effect of herbal plant extract (Hibiscus sabdariffa) in maintain the antioxidant activity of decaffeinated green tea from various parts of Assam.

In the present study, two extraction methods, hot water extraction and ethyl acetate extraction were used to decaffeinate fresh green tea leaf (Camellia assamica) collected from four parts of Assam, NE-India. Both type of extraction methods have significant effect on the antioxidant activity of decaffeinated green tea. Amongst the four samples, Dhekiajuli sample have highest antioxidant activity and total polyphenol as well as flavonoid contents. During hot water extraction (100 °C for 3 min), in decaffeinated green tea, the antioxidant activity decreases to 996.1 ± 26.12 mM TE/g green tea and 1165 ± 31.25 mM TE/g green tea from 1403.07 ± 70.15 mM TE/g and 1587.1 ± 79.355 mM TE/g green tea as observed for caffeinated green tea by DPPH and FRAP assay respectively. Again more antioxidant activity (ranges from 996.1 ± 15.8 to 1421.3 ± 71.06 mM TE/g) was recorded for ethyl acetate extracts compared to hot water extracts of samples. However, the loss in antioxidant activity, due to decaffeination of green tea in our study was minimize by using herbal plant extract, Hibiscus sabdariffa along with the tea extract which shows a synergistic effect.

Development of Well-Preserved, Substrate-Versatile Latent Fingerprints by Aggregation-Induced Enhanced Emission-Active Conjugated Polyelectrolyte.

The development of highly efficient latent fingerprint (LFP) technology remains extremely vital for forensic and criminal investigations. In this contribution, a straightforward, rapid, and cost-effective method has been established for the quick development of well-preserved latent fingerprint on multiple substrates, including plastic, glass, aluminum foil, metallic surfaces, and so forth, without any additional treatment, based on aggregation-induced enhanced emission-active conjugated polyelectrolyte (CPE) 3,3'-((2-(4-(1,2-diphenyl-2-(p-tolyl)vinyl)phenyl)-7-(7-methylbenzo[c][1,2,5]thiadiazol-4-yl)-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl))bis(1-methyl-1H-imidazol-3-ium) bromide, revealing clearly the third-level details (ridges, bifurcations, and pores) with high selectivity, high contrast, and no background interference even by blood stains, confirming the ability of the proposed technique for LFP detection with high resolution. The LFP development process was accomplished simply by immersing fingerprint-loaded substrate into the CPE solution for ∼1 min, followed by shaking off the residual polymer solution and then air drying. The CPE was readily transferred to the LFPs because of the strong electrostatic and hydrophobic interaction between the CPE molecules and the fingerprint components revealing distinct fluorescent images on various smooth nonporous surfaces.

Anion-Exchange Induced Strong π-π Interactions in Single Crystalline Naphthalene Diimide for Nitroexplosive Sensing: An Electronic Prototype for Visual on-Site Detection.

A new derivative of naphthalene diimide (NDMI) was synthesized that displayed optical, electrical, and visual changes exclusively for the most widespread nitroexplosive and highly water-soluble toxicant picric acid (PA) due to strong π-π interactions, dipole-charge interaction, and a favorable ground state electron transfer process facilitated by Coulombic attraction. The sensing mechanism and interaction between NDMI with PA is demonstrated via X-ray diffraction analysis, (1)H NMR studies, cyclic voltammetry, UV-visible/fluorescence spectroscopy, and lifetime measurements. Single crystal X-ray structure of NDMI revealed the formation of self-assembled crystalline network assisted by noncovalent C-H···I interactions that get disrupted upon introducing PA as a result of anion exchange and strong π-π stacking between NDMI and PA. Morphological studies of NDMI displayed large numbers of single crystalline microrods along with some three-dimensional (3D) daisy-like structures which were fabricated on Al-coated glass substrate to construct a low-cost two terminal sensor device for realizing vapor mode detection of PA at room temperature and under ambient conditions. Furthermore, an economical and portable electronic prototype was developed for visual and on-site detection of PA vapors under exceptionally realistic conditions.

The effect of inorganic/organic dual dielectric layers on the morphology and performance of n-channel OFETs.

The optimization of dual dielectric layers by incorporating poly(vinyl alcohol) (PVA), poly(methyl methacrylate) (PMMA), polystyrene (PS) or poly(4-vinylphenol) (PVP) in combination with Al2O3 resulted in immensely improved OFET characteristics with N,N'-bis(cyclohexyl)naphthalene diimide (NDI-CY2) as the active material. The influence of the polymer dielectric layer on the growth morphology of NDI-CY2 and the structural characterization were investigated using atomic force microscopy (AFM) and thin film XRD analysis. The bottom-gate top-contact OFET devices fabricated on glass substrates with Al contact electrodes demonstrated excellent n-channel behavior in the presence of the Al2O3/PVA dual dielectric with the highest electron mobility (µe) value of 0.08 cm(2) V(-1) s(-1), threshold voltage (VTH) as low as 0.5 V and current on/off ratio (ION/IOFF) of 10(4) with an operating voltage of 5 V respectively under vacuum.

Conjugated Polymer Nanoparticles for the Amplified Detection of Nitro-explosive Picric Acid on Multiple Platforms.

Spontaneously formed conjugated polymer nanoparticles (CPNs) or polymer dots displayed remarkable fluorescence response toward nitroexplosive-picric acid (PA) in multiple environments including 100% aqueous media, solid support using portable paper strips and vapor phase detection via two terminal device. This new cationic conjugated polyelectrolyte (CPE) poly(3,3'-((2-phenyl-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl))bis(1-methyl-1H-imidazol-3-ium)bromide) (PFMI) was synthesized by Suzuki coupling polymerization followed by post functionalization method without employing any hectic purification technique. Highest quenching constant value (K(sv)) of 1.12 × 10(8) M(-1) and a very low detection limit of 30.9 pM/7.07 ppt were obtained exclusively for PA in 100% aqueous environment which is rare and unique for any CPE/CPNs. Contact mode detection of PA was also performed using simple, cost-effective and portable fluorescent paper strips for achieving on-site detection. Furthermore, the two terminal sensor device fabricated with nanoparticles of PFMI (PFMI-NPs) provides an exceptional and unprecedented platform for the vapor mode detection of PA under ambient conditions. The mechanism for the ultrasensitivity of PFMI-NPs probe to detect PA is attributed to the "molecular-wire effect", electrostatic interaction, photoinduced electron transfer (PET), and possible resonance energy transfer (RET).

High-performance n-channel organic thin-film transistor based on naphthalene diimide.

A conjugated molecule comprising 1,4,5,8-naphthalene diimide (NDI) substituted with two octadecylamine (OD) chains has been synthesized (NDI-OD2) in a single step from commercial materials, and its organic thin-film transistor (OTFT) devices on glass substrate have been studied using poly(vinyl alcohol) (PVA) gate dielectric material. Although we utilized the PVA dielectric without any intermediate buffer layer or PVA cross-linkers, excellent electron mobility as high as ∼1.0 cm(2)V(-1) s(-1) are obtained. This NDI-OD2 molecule exhibits comparable optical (Eg(UV) ∼3.1 eV) and electrochemical band gaps (Eg(CV) ∼3.02 eV) with a lowest unoccupied molecular orbital (LUMO) energy levels of ∼3.3 eV. When processed by solution method, this material forms rod-shaped crystalline microstructures, whereas, when thermally deposited, it assumes the formation of smooth 2D films. The chemical as well as physical properties and theoretical calculations of NDI-OD2 have been studied and the effect of the C-18 alkyl chain unit has been discussed. The OTFT consisting of NDI-OD2 exhibits excellent performance parameters such as high electron mobility (µe) and Ion-to-Ioff ratio. After demonstrating the high performance of NDI-OD2-based TFT devices fabricated with biocompatible PVA dielectric, we have also demonstrated that these devices can be degraded because of the presence of this PVA dielectric when exposed to a high-moisture environment. The systematic degradation of the device activity in a controlled way within 10 days of exposure (>80% moisture) is also presented here. In this study, a conceptually important feature and futuristic aspect that the n-channel TFT devices can also be biodegraded irreversibly is demonstrated. This concept of developing a low cost and biodegradable OTFT device with biocompatible PVA dielectric with excellent electron mobility is expected to have diverse applications in disposable electronic tags, biomedical devices, and food industry packing.