Browsing by Author "Arpita Maurya"

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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.
Fluorene and Triazine-Based Conjugated Polymer Networks with Tuned Frontier Orbital Energy Levels for Improving Organic Photocatalysis
(American Chemical Society, 2024) Raj Laxmi; Anshuman; Neelam Gupta; None Anamika; Arpita Maurya; Ravi Prakash Behere; Rahul Sharma; Biswajit Maiti; Biplab K. Kuila
Here, we describe a method for fine-tuning the frontier orbital energy levels or redox potential of a conjugated polymer network (CPN) consisting of triazine and fluorene by systematically introducing electron-withdrawing groups at the fluorene moiety through simple structural modification. The band gap of CPN decreases with an increase in the strength of the electron-withdrawing group, and the relative position of the frontier orbital energy becomes more favorable for reactions like photocatalytic aerobic oxidation, which has been further confirmed by theoretical and experimental studies. The CPN with a CN group at the 9 position of fluorene (CPN3) shows the maximum photocatalytic activity (32% higher) compared to CPN1 (hydrogen at the 9 position) in white light. The best-performing catalyst CPN3 was further employed for photocatalytic reactions under white light, like the oxidation of alcohols to carbonyl and boronic acid to the corresponding alcohol, which show noteworthy characteristics like low catalyst loading, high yield, and selectivity with broad substrate scope (aliphatic, aromatic, biphenyl, and heterocyclic). CPN3 exhibited turnover frequencies of 13.33 and 10.9 mmol g-1 h-1 in 3 W blue and white LED lights, respectively, which are much higher than those of state-of-art photocatalysts. The recyclability of the catalyst was tested for up to 5 cycles without much change in the catalytic activity. The practical usefulness of the suggested method was further demonstrated by the CPN3-photocatalyzed gram-scale synthesis of high-value chemicals such as acetophenone from 1-phenylethanol and phenol from phenylboronic acid. © 2024 American Chemical Society.
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.
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
Side-Chain Polarity-Dependent Photoluminescence and Deep Blue Electroluminescence in Fluorene-Based Conjugated Polymer Networks
(American Chemical Society, 2025) None Anamika; Neelam Gupta; Dipanshu Sharma; Arpita Maurya; Anil Kumar; Jwohuei Huei D. Jou; Biplab Kumar Kuila
The development of solution-processable deep blue electroluminescent materials has recently attracted considerable interest in organic light-emitting diode (OLED) research. Here, we report two solution-processable, highly fluorescent, and wide band gap conjugated polymer networks (CPNs) consisting of triazine and fluorene. Two different side chains, alkyl and ethylene glycol, are introduced into the polymer backbone to investigate the effect of side-chain polarity on the fluorescence and electroluminescence properties of the polymer. The thermal, photophysical, and self-assembly properties of the polymer were studied in detail, showing high thermal stability, side-chain polarity-dependent self-assembly, and fluorescence properties in the solid state. The polymer network with an alkyl side chain shows a deep blue color, whereas the ethylene glycol side chain displays a green color. Using these polymer networks, one can create fluorescence patterns of blue and green using UV light. OLEDs based on FCPN2 with an ethylene glycol chain show a maximum quantum efficiency (EQE) of 2.7%, which is much higher than the 0.5% displayed by FCPN1 with an alkyl side chain. FCPN2 exhibits a maximum brightness of 1458 cd/m2 and a maximum current efficiency of 1.2 cd/A with deep blue emission. These findings underscore the potential of side-chain polarity to modify the fluorescence and improve the electroluminescence performance of conjugated polymer-based blue OLED devices. © 2025 American Chemical Society.