Browsing by Author "Biplab Kumar Kuila"

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A hydrogen bond cross-linked luminescent supramolecular network polymer and its application for the detection of alkyl iodides with differentiation capabilities from aromatic iodides
(Royal Society of Chemistry, 2021) Ravi Prakash Behere; Rajlaxmi; Neelam Gupta; Susmita Roy; Ram Nayan Gautam; Manoj Kumar Bharty; Chanchal Chakroborty; Biplab Kumar Kuila
Here, we have demonstrated a luminescent network polymer through a H-bond cross-linking strategy by connecting poly(4-vinyl pyridine) chains with perylene diimide (PDI) cross-linker. The formation of a network structure through hydrogen bonding is successfully proved from the combined study of FTIR, NMR, XRD, and viscosity. The XRD study indicates improved crystallinity with an increased number of sharp reflection peaks, whereas the AFM study reveals self assembly into fibrils and sphere-like nanostructures. These network polymers have been used for the first time for fluorometric detection of a range of commonly employed alkylating agents at low concentrations. Interestingly, the network polymer can also differentiate between alkyl iodides and aromatic iodides. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.
A palladium nanoparticle implanted polymer membrane for reusable dip-catalysis of diverse C-C and C-heteroatom (O/S/N) coupling reactions
(Royal Society of Chemistry, 2023) Raj Laxmi; Ravi Prakash Behere; Arunava Manna; Biplab Kumar Kuila
The criteria for the development of a successful catalyst are simple yet cheap fabrication, high efficiency, stability, flexibility, straightforward recovery, reusability, and ease of scale-up. There are reports of palladium nanoparticle (PdNP)-based catalysts for performing carbon-carbon cross-coupling reactions, but the aforesaid criteria are rarely met in a single system. Moreover, a single catalyst system performing different types of C-C and C-heteroatom cross-coupling reactions is very rare. Herein, we achieved the above-mentioned criteria by using a reusable polymer-embedded Pd nanoparticle dip-catalyst membrane without any other ligands or additives under milder reaction conditions. The composite membrane was fabricated by simply depositing poly(4-vinyl pyridine) anchored PdNPs (average size 9.9 nm) onto a nylon-6 membrane followed by UV cross-linking. C-C bond formation reactions using diverse reagents (Suzuki-Miyaura, Heck, Sonogashira, Stille, Hiyama reactions) were achieved to give the desired products in high to excellent isolated yields, while C-X (X = N/O/S) bond formations were accomplished in moderate to good isolated yields. The turnover number (TON) and frequency (TOF) for the Suzuki-Miyaura cross-coupling reaction are calculated as ≥×104 and 3.11 s−1, respectively. The P4VP-PdNP dip-catalyst system was stable under the reaction conditions without significant leaching of Pd into the solution. The dip-catalyst membrane can be reused at least 10 times without losing any significant activity. The substrate scope for most of the cross-coupling reactions was tested, which indicates functional group tolerance and that the coupling reaction can take place with moieties having electron donating or withdrawing groups. © 2023 The Royal Society of Chemistry
Aligned Proton-Conducting Graphene Sheets via Block Copolymer Supramolecular Assembly and Their Application for Highly Transparent Moisture-Sensing Conductive Coating
(Wiley-Blackwell, 2019) Soumili Daripa; Koomkoom Khawas; Santanu Das; Ratan Kumar Dey; Biplab Kumar Kuila
Here, we have demonstrated a well-defined strategy to prepare highly sulphonated reduced graphene oxide (S-rGO) sheets via non-covalent modification of rGO with water soluble rod-coil conjugated block copolymer poly(3-hexylthiophene)-block-poly(4-styrenesulfonic acid) (P3HT-b-PSSA) carrying a long PSSA block. S-rGO sheets are highly water soluble and its aqueous solution can be used to fabricate highly transparent conductive thin film coating on versatile smooth substrate surfaces like glass, indium tin oxide (ITO), quartz and flexible PET. The successful anchoring of sulfonic acid group on rGO surface via non-covalent modification by P3HT-b-PSSA was confirmed and analyzed by FTIR and XRD study. The bulk morphology of S-rGO reveals sheet like morphology where individual sheets are aligned with each other in a parallel arrangement through intercalation of PSSA chains driven by block copolymer self- assembly. AFM image of the thin film also supports nice parallel alignment of S-rGO sheets of average thickness ∼100 nm on substrate surface. S-rGO sample shows very high water uptake (∼91% in comparison to its initial weight) and proton conductivity 0.5 S/cm after water vapor exposure for 1 hour. Such high proton conductivity is due to the synergy of alignment of graphene sheets with a continuous network of proton conducting nanochannels created by block copolymer microphase separation on the rGO surface. Nyquist plot with two semicircles suggested the presence of grain boundaries in the sample. I−V measurement of transparent thin film device fabricated from S-rGO sheets shows linear behavior with systematic increase of current on increasing water vapor exposure time. The block copolymer device shows well correlated, systematic and reversible resistance change with relative humidity (RH) confirming its efficient sensing capability towards moisture. We believe that high proton conductivity and interesting, reversible moisture sensitive electrical property of this material will be useful in fabricating transparent and flexible moisture sensors, flexible electronics, moisture induced energy storage, fuel cell, biological applications and others. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Carbon dots as a sustainable electrolyte enhancer in aqueous alkaline electrochemical capacitors
(Elsevier Ltd, 2024) Gayathry Ganesh; Vaishak Sunil; JinKiong Ling; Ummiya Qamar; Izan Izwan Misnon; Biplab Kumar Kuila; Santanu Das; Chun-Chen Yang; Rajan Jose
In the endeavour to increase the energy density and to widen the potential window of aqueous alkaline electrochemical capacitors (EC), this study explores the role of carbon dots (CDs) as an additive in potassium hydroxide electrolyte. The CDs with an average size of ∼2.2 nm and negative surface potential are synthesized from a dispersion of palm kernel shell powder in water using a low-temperature hydrothermal process. Electrochemical measurements show that the CD–electrolyte ion (K+) interaction has improved counter ion adsorption in porous carbon electrodes via lowering the characteristic resistances and time constants, which significantly improved the fraction of adsorbed charges than diffusively stored. The improved ionic conductivity is attributed to the improved wettability introduced by the hydrophilic functional groups in the CDs. These parametric changes widened the potential window and marked an 80 % increase in the specific energy and over a 10 % increase in specific power in a practical EC with similar mass-loading as commercial devices. The device with CDs demonstrated superior cycling stability and Coulombic efficiency than the control device without them. These findings underscore the potential of CDs as a promising avenue for advancing the performance parameters of aqueous electrolyte EC, aligning with the overarching goal of realising economical, environmentally friendly, and sustainable energy storage solutions. © 2024
Donor-acceptor organic nanostructure based on conjugated polymer for improving visible-light-driven photocatalytic activity towards degradation of dye in aqueous medium
(Royal Society of Chemistry, 2022) Ravi Prakash Behere; Raj Laxmi; Neelam Gupta; Uttam Sharma; Santanu Das; Biplab Kumar Kuila
Conjugated-polymer-based donor-acceptor hybrid nanostructures have been the subject of great interest, mainly due to their potential applications in photovoltaic and other electronic and optoelectronic devices. Here, we have demonstrated a different aspect of these hybrid nanostructures toward efficient photocatalysis in an aqueous medium. The hybrid donor-acceptor nanostructures were prepared by assembling a carboxylic acid-functionalized fullerene molecule (phenyl C-61 butyric acid) (PCBA) on the surface of an amine-functionalized regioregular P3HT nanostructure through acid-base interaction. The efficient photoinduced charge separation and charge transfer in the hybrid material were investigated by steady-state and time-resolved photoluminescence and photocurrent measurements. The photocatalytic activity of the hybrid nanostructure in water under visible light irradiation (using a 20 W white LED bulb) was investigated, and it was found to show 82.5% dye degradation efficiency. To facilitate the reusability of the photocatalyst, a membrane-based dip-photocatalyst was developed from this material, and it shows 87.5% dye degradation efficiency and can be reused multiple times without a significant change in degradation efficiency. © 2022 The Royal Society of Chemistry.
Efficient Moisture-Induced Energy Harvesting from Water-Soluble Conjugated Block Copolymer-Functionalized Reduced Graphene Oxide
(American Chemical Society, 2021) Soumili Daripa; Koomkoom Khawas; Ravi Prakash Behere; Rampal Verma; Biplab Kumar Kuila
This Research Article demonstrates a very simple approach of a moisture-induced power-generating phenomenon using water-soluble rod-coil conjugated block copolymer (poly(3-hexythiophene)-block-poly(4-styrenesulfonic acid) (P3HT-b-PSSA)-modified reduced graphene oxide. The block copolymer-modified reduced graphene oxide (BCP-RGO) was prepared by noncovalent surface functionalization cum in situ reduction of graphene oxide. A simple device made from BCP-RGO can generate voltage upon exposure to water vapor or under different humidity conditions. The open-circuit voltage generated from the diode-like device varies with respect to the relative humidity, and the device can act as a self-powered humidity sensor. The as-prepared BCP-RGO is able to produce a maximum power density of 1.15 μW/cm2 (short-circuit current density JSC = 6.40 μA/cm2) at a relative humidity of 94%. Meanwhile, the BCP-RGO device produces a very high power density of 0.7 mW/cm2 (at a short-circuit current density of 1.06 mA/cm2) after 91% water absorption. We believe that the material presented here will be very useful for a self-biased humidity sensor and moisture-induced energy harvesting. The diode-like response of the BCP-RGO device with humidity or after water absorption will make the material applicable for self-biased humidity-controlled electronic switching. © 2021 The Authors. Published by American Chemical Society.
Efficient Photoinduced Charge Transfer between Linear Conjugated Polymer and Polymer Network for Light Harvesting Application
(American Chemical Society, 2025) Neelam Gupta; Anamika; Arpita Maurya; Sobhan Hazra; Bhola Nath Pal; Biplab Kumar Kuila
The development of light-harvesting systems based on a donor-acceptor heterostructure for efficient conversion of light to renewable energy is an emerging area of research. Here, we have demonstrated an efficient donor-acceptor heterostructure by hybridizing a high-band gap conjugated polymer network (CPN) with a linear conjugated polymer P3HT to boost charge separation and the light-harvesting property. Steady-state and time-resolved spectroscopic studies show efficient photoinduced electron transfer from P3HT to CPN and simultaneous hole transfer from CPN to P3HT due to the proper alignment of the band gap. The light-harvesting property of the hybrid materials was demonstrated by employing the hybrids as active layers for the fabrication of all polymer photodiodes which show photodetectivity from ultraviolet A to the entire visible region with high responsivity (0.85 A/W) and detectivity of 2.41 × 1011 Jones at 620 nm and −5 V in a CPN/P3HT blend of 1:1. The repetitive on-off switching of a photodetector at zero bias clearly indicates its ability to operate in self-biased mode. This result will open up more possibilities for designing a light-harvesting system based on a high-band gap conjugated polymer network that can utilize UV and visible regions of solar light. © 2025 American Chemical Society.
Electrochemical and Electronic Properties of Transparent Coating from Highly Solution Processable Graphene Using Block Copolymer Supramolecular Assembly: Application toward Metal Ion Sensing and Resistive Switching Memory
(American Chemical Society, 2018) Koomkoom Khawas; Soumili Daripa; Pallavi Kumari; Biplab Kumar Kuila
Here, we have discussed the preparation of a highly solution processable graphene from a novel supramolecular assembly consisting of block copolymer polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) and pyrenebutyric acid (PBA)-modified reduced graphene oxide (RGO). The PBA molecules anchored on the graphene surface form supramolecules with PS-b-P4VP through H-bonding between the carboxylic acid group of 1-pyrenebutyric acid and the pyridine ring of P4VP. The formation of a supramolecular assembly results in a highly stable solution of reduced graphene oxide in common organic solvents, such as 1,4-dioxane and chloroform. Highly transparent and mechanically stable thin films can be deposited from these supramolecular assemblies on a relatively smooth surface of different substrates such as silicon wafer, glass, indium tin oxide, and flexible polymer substrates like poly(ethylene terephthalate). The graphene surface modifier (PBA) can be selectively removed from the thin film of the hybrid material by simple dissolution, resulting in a porous structure. Hybrid thin films of around 50 nm thickness exhibit interesting electrochemical properties with an areal capacitance value of 17.73 μF/cm2 at a current density of 2.66 μA/cm2 and good electrochemical stability. The pendent P4VP chains present in the composite thin film were further exploited for electrochemical detection of metal ions. The electrical measurement of the thin film sandwich structure of the composite shows a bipolar resistive switching memory with hysteresis-like current-voltage characteristics and electrical bistability. The OFF state shows ohmic conduction at a lower voltage and trap-free space-charge-limited current (SCLC) conduction at high voltage, whereas the ON state conduction is controlled by ohmic at low bias voltage, trap-free SCLC at moderate voltage, and tarp-assisted SCLC at high voltage. © 2018 American Chemical Society.
Engaging a highly fluorescent conjugated polymer network for probing endogenous hypochlorite in macrophage cells: improved sensitivity via signal amplification
(Royal Society of Chemistry, 2025) Rikitha S. Fernandes; Neelam Gupta; Ch Sanjay; Anamika; Ambati Himaja; Balaram Ghosh; Biplab Kumar Kuila; Nilanjan Dey
We have employed a triazine-based conjugated polymer network (CPN) for the selective detection of hypochlorite in a semi-aqueous environment. CPNs have been widely employed in gas capture, separation, and adsorption, but the fluorescent properties of CPNs possessing extensive p-conjugated systems tend to be unexplored. Herein, we report the photophysical properties of the CPN and investigate its sensing capability towards hypochlorite. Spectroscopic investigations reveal that the CPN forms p-stacked aggregates in aqueous medium, while loose aggregates were observed to be formed in hydrophobic solvents. The fluorogenic CPN demonstrates remarkable selectivity via fluorescence quenching and a blueshift response towards hypochlorite in a semi-aqueous medium, accompanied by a color change under UV light. Such a turn-off fluorescence response, along with the blue shift upon hypochlorite sensing, was attributed to the oxidation of the sulfur atom of the thiophene functionality of the CPN, consequently resulting in suppression of Intramolecular Charge Transfer (ICT) in the corresponding oxidized adduct. The fluorescence intensity of the CPN exhibits a linear response to hypochlorite concentration, achieving a low detection limit of 1.2 nM. Furthermore, the practical applicability was demonstrated by the detection of hypochlorite in water samples and fluorescent test-paper strips. Additionally, the present system is utilized for bio-imaging of endogenous hypochlorite in RAW 264.7 cells. © 2025 The Author(s)
Enhancement of the electrochemical performance of a cathodically coloured organic electrochromic material through the formation of hydrogen bonded supramolecular polymer assembly
(Elsevier B.V., 2022) Sayan Halder; Ravi Prakash Behere; Neelam Gupta; Biplab Kumar Kuila; Chanchal Chakraborty
Herein, we have developed an H-bonded network polymer architecture with improved crystallinity and photophysical properties through a supramolecular interaction between carboxylic acid-containing perylenebisimide (PBI) cross-linker and poly(4-vinyl pyridine) (P4VP) polymer chains. The H-bonded supramolecular polymers (SMPs) are thoroughly characterized using 1H NMR, FTIR, XRD, and AFM studies. The XRD reveals higher molecular packing, long-range ordering, and better crystallinity after supramolecular assembly formation, while AFM confirms the fibril and sphere-like nanostructures in the SMP networks with decreased diameters. The long-range ordering and nanoaggregate structures in SMP benefit the network structure for better diffusion of counter ions during the redox reaction of the PBI moieties. The electrochromic (EC) measurements of the films divulge the similar reversible EC colour change of the PBI and SMP films from pristine red to deep violet along with vis-to-NIR electrochromism between the −2 V to +1 V potential sweeping along with the significant improvement of the EC parameters in SMP films compared to pristine PBI film. The colouring time (red to deep violet) is improved by 63% (5.6 s–2.2 s), while the bleaching time (deep violet to red) is speeded up by 51% (8.4 s–4.1 s) along with the increment in colouration efficiency by 50% (52.3 cm2/C to 78.1 cm2/C). Therefore, this report is very advantageous to deliver a simple and viable strategy for the enhancement of the EC parameters of organic electrochromes through the generation of ordered H-bonded polymer network formation. © 2022 Elsevier B.V.
Hierarchical Polyaniline-MnO2-Reduced Graphene Oxide Ternary Nanostructures with Whiskers-Like Polyaniline for Supercapacitor Application
(Wiley-Blackwell, 2017) Koomkoom Khawas; Pallavi Kumari; Soumili Daripa; Ramesh Oraon; Biplab Kumar Kuila
Here, we have demonstrated a straight forward and easy synthetic route for preparation of three dimensional hierarchical and porous polyaniline (PANI)/manganese dioxide (MnO2)/reduced graphene oxide (rGO) ternary hybrid nanomaterials with surface decorated by ordered PANI whiskers. The nanostructured material shows different well defined morphology like tubular fiber, sphere which resembles natural tubular wiregrass sedge and spherical cactus. The simple removal of graphene surface modifier through selective dissolution from nanohybrids results further porous structure. The ternary hybrid materials show varying capacitance values depending on composition and nanostructured morphology with the best capacitance value of 762 F/g at current density 1.4 A/g with good electrochemical stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Highly Fluorescent Conjugated Polymer Network as Reversible and Colorimetric Probe for Ultrafast Detection of BF3 and Amine
(American Chemical Society, 2025) None Anamika; Neelam Gupta; Arpita Maurya; Biplab Kumar Kuila
Herein, we have designed and synthesized a fluorescent conjugated polymer network (CPN) for the detection of BF3 and amine. The theoretical and photophysical study clearly indicates the presence of a twisted intramolecular charge transfer (TICT) process in the polymer resulting in strong fluorescence. Upon interacting with BF3, the probe CPN exhibited a significant “turn-off” in fluorescence and also the appearance of a broad peak around 450 nm in UV-vis absorption spectra. The probe showed high and rapid sensitivity for BF3 with a low detection limit (161 nM). Further, the CPN·BF3 complex was utilized for rapid and sensitive detection of amine, which shows “turn-on” behavior in fluorescence. Using NMR, FTIR, and density functional theory (DFT) analysis, the sensing mechanism was thoroughly confirmed. Additionally, test paper-based portable detecting devices for BF3 and volatile amines such as triethylamine in the gas phase were successfully prepared using this probe. Thus, CPN as a fluorescent probe has potential applications in chemical and industrial applications for the sensitive and selective detection of toxic species such as BF3 and amine. © 2025 American Chemical Society.
Highly Water-Soluble Rod–Coil Conjugated Block Copolymer for Efficient Humidity Sensor
(Wiley-VCH Verlag, 2019) Koomkoom Khawas; Soumili Daripa; Pallavi Kumari; Santanu Das; Ratan Kumar Dey; Biplab Kumar Kuila
In this report, the preparation of highly water-soluble rod–coil conjugated block copolymer poly(3-hexylthiophene)-b-polystyrenesulfonic acid (P3HT-b-PSSA) is demonstrated using a facile method with its moisture sensing properties. The block copolymer synthesis method comprises Kumada catalyst transfer polymerization and atom transfer radical polymerization from a bifunctional initiator followed by sulfonation of polystyrene using moderate reaction conditions. The polymerization results in the synthesis of well-defined block copolymers with controllable block length. The successful synthesis of the block copolymer is studied by NMR and FTIR spectroscopy while optical and structural properties of the block copolymer are investigated using UV–vis, photoluminescence spectroscopy, XRD, and FESEM. In water, the block copolymer shows aggregated structure with crystalline core formed by rod-like P3HT chain with absorption maxima at 558 nm, whereas in solid state the absorption maxima is blue shifted to 548 nm. The proton conductivity of the block copolymer P3HT-b-PSSA with ≈91% of PSSA (by weight) is measured from impedance study, and the values for bulk and grain conductivities are 5.25 × 10−4 and 4.66 × 10−6 S cm−1, respectively, at room temperature. The as-synthesized block copolymer shows a very high water uptake with maximum ≈80% in comparison with its initial weight. The I–V measurement of the device made from block copolymer shows nonlinear, rectifying characteristic and the current increases with increase of relative humidity (RH%). The block copolymer device shows well-correlated systemic and reversible resistance change with RH both in doped and undoped state. It is believed that the interesting and highly reversible moisture-sensitive electronic properties of this block copolymer will be useful for the fabrication of moisture-sensitive polymer-based flexible electronic devices. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Mesoporous Mn3O4 coated reduced graphene oxide for high-performance supercapacitor applications
(Institute of Physics Publishing, 2019) Biplab Kumar Kuila; Shaikh Mohammed Zaeem; Soumili Daripa; Kanak Kaushik; Saral Kumar Gupta; Santanu Das
We report the facile synthesis of mesoporous Mn3O4 coated reduced graphene oxide (rGO) nanocomposite using a simple low temperature wet chemical process and demonstrated the nanocomposite material as high-performance electrodes for electrochemical supercapacitor. The nanocomposite structure is unique as it consists of an ultra-thin, mesoporous (pore size ∼1.9-2.6 nm) with oriented pore size of Mn3O4 layer deposited on the surface of rGO. The structure and the orientation of nanopores in the Mn3O4 layer were further confirmed using HRTEM, while structural and morphological analysis were carried out using XRD, Raman spectroscopy, SEM, TEM, and SAED. The pore size and the pore distributions were verified using BET surface area technique, which demonstrated the nanocomposite exhibits uniform distribution of pores of dimension ∼1.9-2.6 nm throughout. The electrocatalytic behavior of the nanocomposite was found to be ideal for their use as supercapacitor electrodes as high-performance charge storage devices. Finally, we demonstrate the supercapacitor electrode using Mn3O4-rGO nanocomposite followed by their electrochemical characterizations for electrocatalytic activity for charge storage. The hybrid material shows best capacitance value of 221 F g-1 at current density 0.15 A g-1 with good cycling stability. We believe that our investigations will pave a pathway towards various new applications, including, electrochemical catalysis, sensing, energy harvesting and storage and many more. © 2018 IOP Publishing Ltd.
Metal-Immobilized Micellar Aggregates of a Block Copolymer from a Mixed Solvent for a SERS-Active Sensing Substrate and Versatile Dip Catalysis
(American Chemical Society, 2021) Soumili Daripa; Rampal Verma; Debanjan Guin; Chanchal Chakraborty; Kamlendra Awasthi; Biplab Kumar Kuila
Here, we have reported micellar aggregations of an amphiphilic block copolymer in mixed solvent and their subsequent use as a template for the fabrication of a very dense, tunable metal nanoparticle-decorated surface for SERS and flexible dip catalysis applications. A silver nanoparticle-immobilized layer on silicon substrates shows excellent SERS (surface-enhanced Raman scattering)-based sensing performance for model analyte rhodamine B up to 10-6 M concentration with a well-defined calibration curve. Furthermore, a facile approach to the preparation of metal NP-immobilized BCP membranes as efficient dip catalyst for two model reactions (the reduction of nitrophenol and the Suzuki-Miyaura reaction of iodobenzene or 2,7-diiodofluorene with phenyl boronic acid) is also demonstrated. The Ag NP-decorated film exhibits high efficiency and extensive reusability in a prototype reaction such as the reduction of nitrophenol by sodium borohydride with a very high turnover number, >126 (for a single use), whereas the Pd NP-immobilized film also has a high, ∼100%, reaction yield and extensive reusability and applicable for different aromatic systems. This work provides a new platform for the design and synthesis of a functionalizable, flexible, and highly mechanically stable dip catalyst which is highly demanded in the catalytic production of value-added chemicals and environmental applications such as wastewater treatment. ©
Mn3O4 nanocluster-graphene hybrid for energy storage and electrochemical sensing application
(Springer, 2020) Soumili Daripa; Shaikh Mohammed Zaeem; Biplab Kumar Kuila; Santanu Das
In this report, uniformly dispersed tri-manganese tetra-oxide (Mn3O4) nanoclusters on reduced graphene oxide (rGO) were synthesized and used as an electrode material for high-performance supercapacitor application. HRTEM images associated with SAED and EDS confirm the formation of Mn3O4 nanoclusters on rGO while FTIR shows clear evidence of Mn3O4 nanocluster deposition on rGO. The nanohybrid structure is unique showing uniformly distributed Mn3O4 nanoclusters of size from 2 to 20 nm with the majorities of the cluster sizes are in the range of ~ 5–11 nm. The nanoclusters exhibit trapped mesopores of size ~ 2 nm inside of the clusters surrounded with tiny Mn3O4 nanoparticles, which not only improves the surface properties but also enhances the electrochemical activities of rGO. We believe that the low-temperature, hydrothermal processing of KMnO4 solution leads to the development of such nanoclusters formed by limited growth of ultra-nanosized nucleates deposited on rGO surface under optimized time condition. The nanohybrid shows the highest capacitance value of 181 F/g at a current density of 0.3 A/g along with superior cyclic stability (with ~ 95% capacitance retention upon continuous 2000 cycle). The nanohybrid material was further utilized for electrochemical sensing of H2O2 where anodic current proportionally increases as a function of H2O2 concentrations. We believe that the nanohybrid material described here will have potential applications in the area of high-performance supercapacitor, catalysis, batteries, and non-enzymatic sensors. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Nanoheterostructured materials based on conjugated polymer and two-dimensional materials: Synthesis and applications
(Elsevier, 2020) Biplab Kumar Kuila
The heterostructured materials from different semiconductors play a crucial role in semiconductor industry and widely used as building block for electronic and optoelectronic devices. A heterojunction can be made by interfacing two different semiconductors where the electronic band structure near the interface will change according to electrostatics. The semiconductor heterojunctions have been widely used in solid state devices like solar cell, light emitting diode (LED), photo detector, and semiconductor laser. Two-dimensional nanomaterials (2DNMs), typically derived from bulk phase of layered structured materials, have rapidly engrossed as promising materials due to their intriguing physicochemical properties like unique optical band gap structure, good semiconducting ability, extremely strong light–matter interactions, high mechanical strength, and high surface area. Therefore these materials show wide range of potential applications like chemical sensor, biosensor, batteries, supercapacitors, electronic, and optoelectronic devices. With tremendous progress in the discovery and isolation of 2D materials, there exists a wide library of 2DNMs which includes graphene, silicene, germanene, layered transition metal oxides, phosphorene, hexagonal boron nitride (h-BN), graphitic carbon nitride (g-C3N4), layered double hydroxides, transition metal halides, and transition metal chalcogenides. However, one of the main challenges with the 2D materials is their easy restacking possibility resulting from strong interlayer interactions and high surface energy and thereby decreases available active sites. Whereas, there is an urgent need for new and scalable strategies to control the doping and improve the chemical stability of the 2D semiconductors before realizing their promising and fascinating applications. To overcome the above mentioned challenges, 2D materials (2DMs) are functionalized with small molecules, metal nanoparticles, ionic liquids, self-assembled monolayers, and polymers. The advantages of polymers over other functionalization include wide processability in organic solvent or water, ability of patterning using photolithographic techniques. Therefore the hybridization of 2DMs with polymer is one of the elegant approaches to generate new heterostructures with new functionality that can overcome the disadvantages of individual components and boost the activities of both with effectively upgraded properties. There are mainly two approaches (1) covalent and (2) noncovalent methods for interfacing or attaching the polymer on the 2D surface to generate novel polymer/2DM nanoheterostructured materials. Conjugated polymers (CPs) which have delocalized unsaturated π backbone is considered as organic semiconductor in their undoped state and studied enormously for organic electronic, optoelectronic device and supercapacitor applications. Besides good solubility and intrinsic electronic and optoelectronic features of CPs, theoretical molecular dynamics studies reveal that the strength of π-π interactions between conjugated block and 2DM like graphene surface is much stronger and can effectively tailor the band gap of 2DMs. By tuning the intrinsic electronic properties of both 2D semiconductor and CPs attached to 2D surface, it is expected to control the carrier properties at the heterojunctions that lead to generation of new hybrid materials with fascinating and exciting properties. In principle, these heterostructured materials can combine the advantages of 2DMs with that of CPs and provide platform for different applications like electronic devices, sensor, and energy storage. In this chapter, we will focus on the recent advances on synthesis of CP/2DM heterostructures and their applications. Different types of CPs including poly(thiophene)s (PTs) and poly(3-hexylthiophene) (P3HT), polyaniline (PANI), polypyrroles (PPys) were widely used to make hybrid materials with 2DMs through noncovalent π-π interaction. Whereas, CPs with suitable end-functionalized reactive groups were covalently attached with 2DM surface to form heterostructured materials based on CP and 2DNMs. © 2020 Elsevier Inc.
Ni-Pd bimetallic nanoparticle stabilized polymer membrane as an efficient dip-catalyst for oxidative coupling of aromatic amines to access symmetrical and unsymmetrical azo compounds
(Royal Society of Chemistry, 2025) None Anshuman; Raj Laxmi; Padmini Gupta; Renu Mishra; Neelam Gupta; Biplab Kumar Kuila
The azo linkage is an important chemical motif with wide applications in the pharmaceutical, agrochemical, textile, paint, and food industries. The development of effective dip-catalysts that would convert aromatic amines to symmetric or asymmetric azobenzenes in the presence of aerobic molecular oxygen under mild conditions is really challenging. Here, we have developed a dip-catalyst by immobilizing poly(vinylpyrrolidone)(PVP) stabilized Ni-Pd bimetallic nanoparticles on a nylon-6 membrane through UV-crosslinking for performing such reactions. The catalyst was highly efficient for the oxidative coupling of aromatic amines to the corresponding aromatic azo compounds under aerobic conditions without employing hazardous substances or ecologically harmful nitrites. Notable reaction features include a broad substrate range (aromatic, heterocyclic, and polyaromatic amines), a high yield (∼98%), low catalyst loading, and a simple work-up method. The dip-catalyst exhibits exceptional reusability for multiple catalytic cycles while retaining its high performance and structural characteristics. The gram-scale synthesis of high-value compounds like azobenzene provided additional evidence of the practical utility of the proposed catalyst. © 2025 The Royal Society of Chemistry.
Nitrogen- and Sulfur-Enriched Conjugated Polymer Network as an Electrocatalyst for the Oxygen Reduction Reaction and as a Cathode Material for Zinc–Air Batteries
(American Chemical Society, 2025) Arpita Maurya; Neelam Gupta; Priti Singh; Nitika Bhutani; Anamika; Rik Rani Koner; Mudit Dixit; Biplab Kumar Kuila
Over the past decade, heteroatom-doped metal-free carbon materials (MFCMs) have been recognized as effective oxygen reduction reaction (ORR) catalysts. However, the active centers for the ORR in MFCMs are difficult to precisely confirm and controllably synthesize using conventional methods such as high-temperature pyrolysis or heteroatom doping. To elucidate the active center precisely and the structure–property relationship, we demonstrated a conjugated polymer network (CPN), TTB, comprising triazine, thiophene, and benzothiadiazole for ORR and as a cathode catalyst for a zinc–air battery. Density functional theory calculations revealed that the benzothiadiazole building block acts as an active center, leading to ORR catalytic activity. TTB was thoroughly characterized through different characterization techniques like FTIR, XPS, XRD, FESEM, HRTEM, and BET surface area and pore size analysis. The onset potential of 0.81 V vs reversible hydrogen electrode (RHE), diffusion-limiting current density of 3.0 mA/cm2, and E1/2of 0.68 V vs RHE with good electrochemical stability are comparable to the benchmark ORR catalyst (10% Pt/C). TTB was further used as the cathode electrocatalyst for a zinc–air battery, resulting in an open-circuit potential of 1.46 V and a specific capacity of 613 mAh g–1. A rechargeable zinc–air battery was also fabricated with TTB and RuO2as the cathode electrocatalysts, showing a voltage gap of 0.9 V and good cyclic stability. These findings show that the rational design and precise synthesis of conjugated polymer networks can facilitate the development of new ORR catalysts useful as cathode materials for zinc–air batteries. © 2025 American Chemical Society
Piezoresistive pressure sensor based on conjugated polymer framework for pedometer and smart tactile glove applications
(Elsevier B.V., 2023) Neelam Gupta; Vivek Adepu; Manav Tathacharya; Sohel Siraj; Subhradeep Pal; Parikshit Sahatiya; Biplab Kumar Kuila
Conjugated polymer frameworks which are generally less solution processable are rarely explored for flexible pressure sensor application in spite of their great potentiality that arises from three dimensional network structure, excellent conductivity, thermal stability and porosity. The report demonstrates the development of conjugated polymer framework (CPF) based flexible piezoresistive sensor and further utilization of the same for real time Pedometer and Smart Tactile Glove applications. CPF was deposited onto the cellulose paper by vacuum filtration method followed by encapsulation with PDMS to improve the flexibility and avoid the interaction of CPF with the ambient. The sensitivity of the fabricated CPF based pressure sensor was observed to be 2.92 kPa−1 with high repeatability and reliability. The transduction mechanism of the CPF based pressure sensor can be attributed to the increase in the contact areas between individual nanostructures when pressure applied and increase the current flow. The fabricated CPF-pressure sensor was further demonstrated for real time applications such as Pedometer which counts the number of steps and also Smart Tactile Glove which finds potential applications towards human machine interface. Dedicated Android applications are developed wherein the analyzed data is displayed to the user with Bluetooth as the medium of data transfer. Successful demonstration of organic materials for the use of physical sensor is a major step ahead in the field of organic electronics and opens up new avenues of research towards low-cost physical sensors for personal healthcare monitoring. © 2022 Elsevier B.V.