@article {48456, title = {Understanding the thermal stability of a 3d, 4d, and 5d element doped aluminium nanocluster through BOMD simulations}, journal = {Molecular Simulation}, volume = {49}, year = {2023}, month = {FEB}, pages = {245-250}, type = {Article}, abstract = {

Endohedrally doped atomic clusters have generated considerable interest among computational chemists on account of their tunable chemical properties that mimic a super atom. Such endohedrally doped clusters have also been experimentally realised in the more recent past. The present work explores the practical existence of 3d, 4d and 5d doped aluminium clusters, more specifically doped Al13 cluster, by evaluating systematically their structural stability through the first principle molecular dynamical simulations. Born-Oppenheimer Molecular Dynamics (BOMD) simulations have been carried out on Al12X atomic clusters where X = Ti, V, Fe, Co, Ni, Cu, Zn, Y, Mo, Ru, Rh and W are in endohedral position. The thermal stability of such endohedrally doped clusters is quantified through parameters such as delta(rms), MSD and is an element of(pro). Electronic structure calculations reveal that endohedral doping of only Rh, Cu and Zn is preferred in the Al-13 cluster. Other dopants prefer to remain on the surface positions. However, finite temperature calculations reveal that the Al12Zn cluster undergoes surface modifications from 300K leading to a distorted icosahedral structure. Al12Cu cluster in quartet spin state is the only thermally stable cluster with Cu remaining in the endohedral position and structure retaining icosahedral confirmation till 700K.

}, keywords = {Al-13 atomic cluster, BOMD simulations, DFT, Endohedral doping, super atom}, issn = {0892-7022}, doi = {10.1080/08927022.2022.2153151}, author = {Samudre, Nikhil S. and Singh, Chandrodai Pratap and Krishnamurty, Sailaja} } @article {49058, title = {Quasi-molecular hydrogen storage capacity of graphene quantum dots: A dispersion corrected DFT study}, journal = {Journal of Energy Storage}, volume = {84}, year = {2024}, month = {APR }, type = {Article}, abstract = {

Efficient storage of hydrogen, green fuel with the highest energy density, remains a pressing challenge. Among the several materials investigated for their potential hydrogen storage, 2D materials, like graphene, have advantages such as mechanical strength and large surface area but fail to store hydrogen reversibly. In this context, the present computational experiment demonstrates the potential of Graphene Quantum Dots (GQDs) with 24, 40 and 42 carbon atoms for their hydrogen storage capacity in quasi-molecular mode. Factors such as edge terminations, heteroatom doping, and anchoring of metal atoms are evaluated as a function of their storage capacity. The study clearly demonstrates an enhanced storage capacity of quantum dots, particularly, when a single Ti adatom is anchored on a 24 carbon atom GQD with a storage weight \% of 2.24 \% w/w. The storage weight \% is further noted to increase as a function of the number of Ti atoms anchored on the GQD with the highest hydrogen storage weight \% of 6.1 \% w/w. Importantly, the adsorption of hydrogen molecule on the Ti atom is through a quasi-molecular mode and is driven by Kubas interaction. This type of interactions makes GQDs as viable storage materials at room temperature. Secondly, the work demonstrates that GQDs offer higher storage capacities of hydrogen molecules as compared to their 2D counterparts viz., graphene sheets, making them attractive candidates to be explored experimentally.

}, keywords = {Density functional theory, graphene quantum dots, Hydrogen storage, Kubas interaction, Quasi -molecular adsorption, Ti adatom}, issn = {2352-152X}, doi = {10.1016/j.est.2024.110833}, author = {Khadilkar, Pranav and Samudre, Nikhil S. and Krishnamurty, Sailaja} } @article {49402, title = {Variations in packing as a function of side chains in random copolymers and its impact on charge carrier mobility}, journal = {Macromolecular Chemistry and Physics}, year = {2024}, month = {OCT }, type = {Article; Early Access}, abstract = {

Homopolymers and alternating copolymers of conjugated molecules exhibit impressive performance in electronic devices. Despite the well-established procedures, the synthesis of alternating copolymers using three monomers is not as easy as random copolymers. Besides facile synthesis, the random copolymers can match the performance of alternating copolymers in electronic devices. Herein, random copolymers are designed and synthesized comprising thienoisoindigo (TIIG), diketopyrrolopyrrole (DPP), and thiophene. The DPP monomers installed with various side chains including branched alkyl chain, branched alkyl chain with ester functionality, linear oligo ethylene glycol, and siloxane terminated alkyl chain are incorporated into the polymers (P1, P2, P3, and P4, respectively). All the thermally stable, low bandgap random copolymers exhibited strong H-type aggregation in thin film. The relationship between thin film microstructure originating from diverse side chains and the charge transport in organic field effect transistors (OFETs) is investigated. All the random copolymers exhibited predominantly p-type charge transport and a maximum hole mobility of 2 x 10-2 cm2 V-1s-1 is observed for P3. The packing of all the polymers is examined theoretically by density functional theory (DFT) and compared with experimental values obtained from grazing incident X-ray diffraction (GIXRD). Various side chains (hydrophilic and hydrophobic) affect molecular packing of random polymers which ultimately affects its thin film morphology and semiconducting performances. Linear chains provide better interchain packing by pi-pi stacking compared to bulky branched side chains. The incorporation of heteroatoms and polar groups into the side chain further enhances the interchain interactions. image

}, keywords = {diketopyrrolopyrrole, organic field effect transistor, random polymer, side chain engineering, thienoisoindigo}, issn = {1022-1352}, doi = {10.1002/macp.202400294}, author = {Swain, Gitanjali and Kumar, Subramani and Samudre, Nikhil S.} }