Browsing by Author "Mahapatra, Santosh K."

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    Flexible zinc oxide photoelectrode for photo electrochemical energy conversion
    (Springer, 2021-05-18T00:00:00) Shiyani, T.; Banerjee, I.; Mahapatra, Santosh K.; Ray, Asim K.
    Photoelectrochemical properties have been investigated for flexible photoelectrodes containing 310�nm thick ZnO film on spin-coated ITO/PET. The high crystalline structure of ZnO was studied using x-ray diffraction pattern. A value of 3.4�eV has been estimated for optical band gap from its absorption spectra. The flexible ZnO photoelectrode was demonstrated to generate photoelectrochemical current. The photocurrents are enhanced by 4% whereas flat-band potential is shifted by 8�V due to the illumination. Values of 1.022 and 0.714 AW?1 were found to be for photo switching and photoresponsivity, respectively. ZnO/ITO/PET can be used as a substrate for making flexible hybrid PEC devices to generate solar power and solar fuels. � 2021, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
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    Synergistic Effect of Crystallization Control and Defect Passivation Induced by a Multifunctional Primidone Additive for High-Performance Perovskite Solar Cells
    (American Chemical Society, 2022-12-22T00:00:00) Saykar, Nilesh G.; Iqbal, Muzahir; Ray, Asim K.; Mahapatra, Santosh K.
    The ionic nature of organic-inorganic metal halide perovskites endows intrinsic defects at the surface of the polycrystalline films. Simultaneous defect passivation during the growth of perovskite films could inhibit defect formation to a great extent. Herein, the anticonvulsant drug primidone (PRM) is demonstrated as a novel additive to control the crystallization and defect passivation of perovskites. The spectroscopic measurements support theoretical predictions showing the strong interaction between active functional groups and PbI2. An amount of PRM is tuned to obtain the perfect perovskite films with improved grain size and crystallinity than their control counterparts. Efficient PbI antisite defect passivation suppresses the non-radiative recombinations, resulting in higher luminance intensity and significantly longer charge carrier lifetimes. The PRM-modified perovskite solar cells (PSCs) show a power conversion efficiency (PCE) of 18.73%, much higher than that of control PSCs (16.62%). The ambient stability of PRM-modified PSCs is meritoriously increased compared to control PSCs. The PRM-modified PSCs show stability retention of up to 85% of the initial PCE after 1000 h, while control PSCs retain only 25% of the initial PCE after 550 h. The multifunctional defect passivation approach with the PRM additive shows the effective way for the efficiency and stability improvement of PSCs. � 2022 American Chemical Society.
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    Synergistically modified WS2@PANI binary nanocomposite-based all-solid-state symmetric supercapacitor with high energy density
    (Royal Society of Chemistry, 2022-03-09T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Alegaonkar, Prashant S.; Mahapatra, Santosh K.
    The rapid development of intelligent, wearable, compact electronic equipment has triggered the need for durable, flexible, and lightweight portable energy storage devices. Nanomaterials that are capable of delivering the high specific power density and commensurate energy density are potential candidate for realizing such devices. Herein, we report the facile synthesis of a binary nanocomposite WS2@PANI by utilizing hydrothermal and physical blending techniques to assess it as an electrode material for high-performance supercapacitors. The nanocomposite electrode delivered specific capacitance >335 F g?1 @ 10 mV s?1 (two-electrode), achieving energy and power densities of ?80 W h kg?1 and ?800 W kg?1, respectively, with capacitance retention of 83% even after 5000 charge-discharge cycles @ 10 A g?1, all of which are superior to the WS2 electrode. Dunns model quantifies capacitive and intercalative contributions that showed the cumulative effect of both to realize a robust, cost-effective, and energy-efficient device. The strategically incorporated PANI broadened the electrochemical window and the device's overall performance, resulting in high specific energy density. We demonstrated that our all-solid-state symmetric supercapacitor could be used to illuminate a light-emitting diode and drive a rotary motor. We believe that our WS2@PANI binary nanocomposite will be a potential candidate for energy storage devices. � 2022 The Royal Society of Chemistry
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    Tellurium nanostructures for optoelectronic applications
    (Springer Science and Business Media Deutschland GmbH, 2022-03-29T00:00:00) Rani, Pinki; Alegaonkar, Ashwini P.; Mahapatra, Santosh K.; Alegaonkar, Prashant S.
    We report on fabrication of tellurium nanostructures (TN) that demonstrated promising applications in optoelectronics. Initially, TN were synthesized using a simple, one-step, room temperature, wet-chemical technique. During synthesis, the effect of number of parameters such as precursor concentration, its content, solvent ratios, their pH and reaction time has been investigated at a temperature ~ 120��C. The obtained product was examined by UV�visible, IR spectroscopy, X-ray diffractometry, electron microscopy and energy-dispersive X-ray spectroscopic characterization techniques. Analysis revealed that TN have profound impact on the structure�property relationship through active and passive participation of Mo catalyst. During its initial growth stages, Te and O bonding gets influenced by Mo to form Mo�O�Te�O and Te�Mo�Te moieties, typically, at 6�h. This has implication onto the structural phase transformation of TN from Te-tube (TT) to Te-flake (TF) and then to TT again. Possible transformation mechanism is explained. Structurally, TN had hexagonal quasi-crystalline atomic arrangement with morphologically thin, transparent, bunched and close-caped TT characteristics having diameter 50�100�nm and length 0.8�2.1��m, whereas TF is found to be thin, geometrically squared with area ~ 7 to 10 �m2. On their implementation for optoelectronic assessments, over the wavelength range 0.3�2.1��m (power density ~ 100 mW/cm2), they showed peculiar luminescent and dark I�V responses. Relevant photocarrier dynamics has been revealed. TT, typically, showed 160% quantum efficiency, whereas TF ~ 40% is useful for optoelectronic devices. Details are presented. Graphical abstract: Fabrication and optoelectronic assessments of tellurium nanostructure that showed time-dependent structural phase transformation from tube to flake to tube. [Figure not available: see fulltext.] � 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.