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Item Thermophysical Assessments on Self-Assembled Tellurium Nanostructures(American Chemical Society, 2023-09-01T00:00:00) Sudheer, Manjima; Rani, Pinki; Patole, Shashikant P.; Alegaonkar, Prashant S.Thermal properties of self-assembled nanostructures are of great importance to explain the structural phase transformation phenomenon. We report on the thermophysical assessments on tellurium nanostructures (TeN) that have been prepared using a facile wet-chemical technique by admixing precursor sodium telluride (Na2TeO3) and sodium molybdate (Na2MoO4) catalysts in hydrazine hydrate solution and heated at 120 �C, over 5-7 h. The extracted products (interval: 0.5 h) were subjected to a number of spectro-microscopic techniques including thermal measurements. Under identical growth conditions, the morphology of TeN was found to be transformed from Te nanotube (TT) to Te nanoflake (TF) at 6 h. Analysis revealed that Mo participated actively during 6 h of growth time, thereby making bonds with oxygen and the Te host lattice. At the vicinity of the phase transformation, Mo acquired an interstitial position in the hexagonal motif due to enhancement in catalytic efficiency that led to the formation of MoO2- moieties, which transiently reacted with host lattices resulting in surface charging of the tubes. This, in turn, created the coalescing effect with neighboring colloidal tubes through the van der Waals interaction. Thermal properties such as thermal conductivity, effusivity, diffusivity, and specific heat studied for TeN showed prominent surface effects. The increased surface area and enhanced amount of polycrystallinity resulted in unprecedently low thermal properties of TF due to severe phonon confinement. � 2023 American Chemical Society.Item 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.Item Synergistic photophysical and electrochemical response of Te @ PANI for energy harvesting(Springer, 2023-01-07T00:00:00) Rani, Pinki; Jewariya, Yogesh; Haldar, Krishna Kanta; Biswas, Rathindranath; Alegaonkar, Prashant S.Materials with synergistic functionality are of great importance in consumer electronics. We report on the preparation and assessments of Te @ PANI composite for energy conversion and storage application. Initially, (5�15%) Te @ PANI composites were synthesized by the facile, room temperature, time and cost-effective solid-state synthesis technique followed by characterizations using Fourier transform infra-red, UV-Visible, energy dispersive spectroscopic including X-ray diffractometry and field electron scanning microscopy. Te exfoliates polymeric segments of PANI by bonding benzenoid rings through sulphonated impurity sites which have a profound impact on symmetry molecular bond vibrations. Its analysis is presented. In photophysical application, both dark and luminescent I-V measurements have been performed that showed a linear variation with minimum photo-resistance offered by 10% composite and reaching current > 10�mA under 1.5�V biased conditions. In storage response, Te @ PANI supercapacitor devices are dominating in inductive coupling over capacitive coupling by ten times. Corresponding shunt impedance is seen to be favourably lower for 10% composition, and respective charge transfer impedance has also followed identical behaviour over other classes of samples. The quality factor of the device for 10% is found to be almost twelve times better. However, at a low scan rate (10�mV/s), the presence of Te has changed the tendency of ion migration, thereby, reducing the magnitude of ion current by about three times with an increase in Te from 5 to 15%. Thus, fabricated composite demonstrated synergistic aspects of energy. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.