Journal Articles authored by NIIST researchers published in 2018 http://localhost:8080/xmlui/handle/123456789/2964 2026-04-11T08:22:30Z 2026-04-11T08:22:30Z Della, T D Suresh, C H http://localhost:8080/xmlui/handle/123456789/3421 2019-07-19T14:20:00Z 2018-02-28T00:00:00Z

Title: Sumanene: an efficient π-bowl for dihydrogen storage Authors: Della, T D; Suresh, C H Abstract: Density functional theory calculations at the M06L/6-311++G(d,p) level show that sumanene (Su), a polycyclic aromatic π-bowl, and its anionic forms possess high dihydrogen binding affinity. The dihydrogen rich systems such as Su(H2)40, Su-(H2)40, and Su2-(H2)40 show interaction energy (Eint) values of 51.7, 63.0 and 87.6 kcal mol-1, respectively. The ion-pair complexes of anionic, dianionic and trianionic sumanenes with K+ also have a significant H2 binding capacity with Eint values of 61.6 kcal mol-1 for Su-K+(H2)47, 77.1 kcal mol-1 for Su2-(K+)2(H2)51 and 132.6 kcal mol-1 for Su3-(K+)3(H2)51. The charge delocalization in the complex increases substantially with an increase in the amount of H2 adsorbed, which parallels with a declining trend in the magnitude of the molecular electrostatic potential (MESP) minimum (Vmin) for Su, Su-, Su2-, Su-K+, Su2-(K+)2, and Su3-(K+)3. Also, using quantum theory of atoms in molecules (QTAIM) analysis, sumaneneH2 noncovalent interactions and secondary dihydrogen interactions within the complex are established by locating bond critical points (bcp). The structured network of noncovalent bonds in the complex accounts for the stability of the complex. Further, by replacing K+ with lighter metals such as Li+ or Na+, a 66-74% increase in Eint is observed for anion-M+ and dianion-(M+)2 ion pairs. Our results prove that sumanene systems possess significant dihydrogen binding affinity, which can be employed in developing efficient hydrogen storage systems.

2018-02-28T00:00:00Z Pradhan, S C Hagfeldt, A Soman, S http://localhost:8080/xmlui/handle/123456789/3420 2019-07-19T14:18:50Z 2018-08-29T00:00:00Z

Title: Resurgence of DSCs with copper electrolyte: a detailed investigation of interfacial charge dynamics with cobalt and iodine based electrolytes Authors: Pradhan, S C; Hagfeldt, A; Soman, S Abstract: Deploying earth abundant copper as a redox mediator in dye-sensitized solar cells (DSCs) has been found to be a very promising strategy to achieve higher photovoltage and power conversion efficiencies in full sun (100 mW cm−2) and in low/diffuse light conditions. Achieving higher photovoltage without compromising photocurrent helped copper electrolyte attract considerable attention among alternate electrolytes currently employed in DSCs. The very small reorganization energy between Cu(I) and Cu(II) and small molecular size helped copper achieve unit regeneration efficiency, with a driving force as low as 100 mV and a high diffusion coefficient (Dn), leading to better diffusion length (Ln) and charge collection efficiency (ηcc). Mass transport issues were also found to be improved for copper electrolytes in comparison with cobalt electrolytes. As it is inert to silver and other electrical contacts used in DSCs and possesses higher mobility even in solid state, copper-based electrolyte is a promising candidate to spearhead the commercialization of dye solar technology. In this regard, a detailed evaluation of internal electron transfer dynamics is highly essential to understand the limiting processes in these devices. In the present study, we performed a comparison between copper, cobalt and iodine electrolytes using the same dye (LEG4), semiconductor (TiO2) and additive concentrations to understand in detail the charge transfer processes leading to higher photoconversion efficiencies and also probe the various deleterious processes taking place in copper devices that provide opportunities to further improve its performance in future.

2018-08-29T00:00:00Z Sharma, I Pattanayek, S K http://localhost:8080/xmlui/handle/123456789/3419 2019-07-19T14:18:03Z 2018-12-01T00:00:00Z

Title: Effect of characteristics of shear force on secondary structures and viscosity of bovine serum albumin solution Authors: Sharma, I; Pattanayek, S K Abstract: We have explored the effect of shear force on aggregate size, the secondary structure of proteins, and the viscosity of protein bovine serum albumin solution. The size of protein aggregates and secondary structures of the protein are dependent on the external variables such as temperature, the magnitude of shear, time of shearing, and process of applying shear. The process of application of shear, which can be continuous or intermittent periodic stoppage, can control the characteristics of aggregates of BSA. The viscosity of the protein solution is expected to depend on the size of the aggregates. We have proposed a mechanism of the association of BSA molecules leading to the formation of aggregates. Small aggregates at 40 °C are formed through the interaction of side chains, while bigger aggregates formed at 60 °C through β-sheet interaction. The indication of the opening of the BSA molecules at an intermediate temperature is confirmed by the appearance of more side chain and random coil. The shear leads to a highly anisotropic structure at a temperature beyond 60 °C and leads to the higher hydrodynamic radius. This makes the solution to undergo transition from dilute to semi-dilute regime and increase in viscosity by a factor fourfold. Subsequently, we have shown that the viscosity depends on the proportion of β-sheet within the aggregate.

2018-12-01T00:00:00Z Banhart, J Pillai, U T S Rajan, T P D Murty, B S http://localhost:8080/xmlui/handle/123456789/3418 2019-07-19T14:16:44Z 2018-11-02T00:00:00Z

Title: Preface on International Conference on Solidification Science and Processing Authors: Banhart, J; Pillai, U T S; Rajan, T P D; Murty, B S Abstract: We are pleased to bring out this special issue of Transactions of the Indian Institute of Metals (TIIM) containing extended version of select papers presented at the Seventh International Conference on Solidification Science and Processing (ICSSP7) held in Thiruvananthapuram during November 19–22, 2018. ICSSP, a triennial international conference, is being organized since 2001 to allow researchers to exchange their knowledge on recent advances in the broader field of solidification. In this series, the ICSSP7 is organized jointly by the National Institute of Interdisciplinary Science and Technology (CSIR-NIIST) and Indian the Institute of Technology Madras. The conference is chaired by Professor John Banhart, Technical University, Berlin, Germany and convened by Dr. U.T.S. Pillai, CSIR-NIIST.

2018-11-02T00:00:00Z