https://libjncir.jncasr.ac.in/xmlui/handle/10572/1538 2026-04-04T05:31:56Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2500 Ultrathin septuple layered PbBi2Se4 nanosheets Chatterjee, Arindom; Guin, Satya N.; Biswas, Kanishka Layered lead bismuth selenide, PbBi2Se4, an intergrowth compound of PbSe (rocksalt) and Bi2Se3 (hexagonal), is a topological insulator in the bulk phase. We present a simple solution based synthesis of two dimensional (2D) few seven atomic (septuple) layered PbBi2Se4 nanosheets (4-7 nm thick) for the first time. The excellent electrical transport in ultrathin PbBi2Se4 is attributed to the presence of dominant surface states that offer high electrical mobility (similar to 153 cm(2) V-1 s(-1)) and scattering resistant carriers. Ultrathin 3-5 SLs PbBi2Se4 shows an n-type semiconducting behaviour with a band gap of similar to 0.6 eV, which is confirmed by optical spectroscopy and thermopower measurements. Restricted Access 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2498 Low-temperature soft-chemical synthesis and thermoelectric properties of barium-filled p-type skutterudite nanocrystals Banik, Ananya; Biswas, Kanishka Bulk skutteruclites, such as cobalt triantimonide (CoSb3) are promising inorganic materials for thermoelectric power generation at high temperatures. Generally, bulk CoSb3 is synthesized by high temperature solid state reactions. Herein, we demonstrate the low temperature solution phase synthesis of p-type nanocrystalline CoSb3 and Ba-filled CoSb3. increase in the temperature dependent Seebeck coefficient with simultaneous increase in temperature dependent electrical conductivity has been observed in the present nano crystalline samples, which is unusual in the case of bulk CoSb3. Efficient phonon scattering by nanoscale grain boundaries and the additional phonon damping due to the rattling of Ba in the void of nanocrystalline CoSb3 give rise to low thermal conductivity, which results in improved thermoelectric performance in nanocrystalline p-type Ba0.048CoSb3. (C) 2014 Elsevier Ltd. All rights reserved. Restricted Access 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2499 Nanostructuring, carrier engineering and bond anharmonicity synergistically boost the thermoelectric performance of p-type AgSbSe2-ZnSe Guin, Satya N.; Negi, Devendra S.; Datta, Ranjan; Biswas, Kanishka Thermoelectric "waste heat-to-electrical energy" generation is an efficient and attractive option for robust and environmentally friendly renewable energy production. Simultaneous tailoring of interdependent thermoelectric parameters, i.e. electrical conductivity, thermopower and thermal conductivity, to improve the thermoelectric figure of merit is the utmost challenge in this field. Another important aspect is to develop high performance materials based on cheap and earth abundant materials. We have chosen AgSbSe2, a homologue of AgSbTe2 containing earth abundant selenium, as a model system for thermoelectric investigation due to its low thermal conductivity and favourable valence band structure. Herein, we show that by integrating different but synergistic concepts: (a) carrier engineering, (b) second phase endotaxial nanostructuring and (c) bond anharmonicity, we can achieve a maximum ZT of similar to 1.1 at 635 K in AgSbSe2-ZnSe (2 mol%), which is significantly higher than that of pristine AgSbSe2. The above system therefore offers promise to replace traditional metal tellurides for mid-temperature power generation. We demonstrate a design strategy which provides simultaneous enhancement of electrical transport through optimized doping, superior thermopower by the convergence of degenerate valence bands, and glass-like thermal conductivity due to the effective scattering of phonons by nanostructuring, bond anharmonicity and a disordered cation sublattice. Restricted Access 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2496 Green ionothermal synthesis of hierarchical nanostructures of SnS2 and their Li-ion storage properties Jana, Manoj K.; Rajendra, H. B.; Bhattacharyya, Aninda J.; Biswas, Kanishka Flower-like hierarchical architectures of layered SnS2 have been synthesized ionothermally for the first time, using a water soluble [EMIM]BF4 ionic liquid (IL) as the solvent medium. At lower reaction temperatures, the hierarchical structures are formed of few-layered polycrystalline 2D nanosheet-petals composed of randomly oriented nanoparticles of SnS2. The supramolecular networks of the IL serve as templates on which the nanoparticles of SnS2 are glued together by combined effects of hydrogen bonding, electrostatic, hydrophobic and imidazolium stacking interactions of the IL, giving rise to polycrystalline 2D nanosheet-petals. At higher reaction temperatures, single crystalline plate-like nanosheets with well-defined crystallographic facets are obtained due to rapid inter-particle diffusion across the IL. Efficient surface charge screening by the IL favors the aggregation of individual nanosheets to form hierarchical flower-like architectures of SnS2. The mechanistic aspects of the ionothermal bottom-up hierarchical assembly of SnS2 nanosheets are discussed in detail. Li-ion storage properties of the pristine SnS2 samples are examined and the electrochemical performance of the sample synthesized at higher temperatures is found to be comparable to that reported for pristine SnS2 samples in the literature. Restricted Access 2014-01-01T00:00:00Z