Papers by Pooja Panchmatia
Structural and electronic properties of CuSbS2 and CuBiS2: potential absorber materials for thin-film solar cells
As the demand for photovoltaics rapidly increases, there is a pressing need for the identificatio... more As the demand for photovoltaics rapidly increases, there is a pressing need for the identification of new visible light absorbing materials for thin-film solar cells that offer similar performance to the current technologies based on CdTe and Cu(In,Ga)Se2. Metal sulphides are the ideal candidate materials, but their band gaps are usually too large to absorb significant fractions of visible light. However, by combining Cu+ (low binding energy d10 band) and Sb3+/Bi3+ (low binding energy s2 band), the ternary sulphides CuSbS2 and CuBiS2 are formed, which have been gathering recent interest for solar cell applications. Using a hybrid density functional theory approach, we calculate the structural and electronic properties of these two materials. Our results highlight the stereochemical activity of the Sb and Bi lone pair electrons, and predict that the formation of hole carriers will occur in the Cu d10 band and hence will involve oxidation of Cu(I).
International Journal of Pharmaceutics, 2013
Salt formation is an effective method of improving physicochemical properties of acidic and basic... more Salt formation is an effective method of improving physicochemical properties of acidic and basic drugs. The selection of a salt form most suitable for drug development requires a well-designed screening strategy to ensure various issues are addressed in the early development stages. Triboelectrification of pharmaceutical powders may cause problems during processing such as segregation of components due to the effects of particle adhesion. However, very little work has been done on the effect of salt formation on triboelectrification properties. In this paper, salts of flurbiprofen were prepared by combining the drug with a selection of closely related amine counter ions. The aim of the work was to investigate the impact of the counter ion on electrostatic charge of the resultant salts to inform the salt selection process. The experimental results show the magnitude of charge and polarity of the flurbiprofen salts to be highly dependent on the type of counter ion selected for the salt formation. Furthermore, particle adhesion to the stainless steel surface of the shaking container and the salts' compression properties were measured. The formed salts had lower electrostatic charges, improved tabletability, and resulted in reduced adhesion of these powders compared with the parent drug.
Journal of Materials Chemistry, 2010
Article Title: Protonic defects and water incorporation in Si and Gebased apatite ionic conductor... more Article Title: Protonic defects and water incorporation in Si and Gebased apatite ionic conductors Year of publication: 2010 Link to published article: http://dx.
The Structure and Morphology of TiO2-B Nanoparticles
Physical Chemistry Chemical Physics, 2012
As the demand for photovoltaics rapidly increases, there is a pressing need for the identificatio... more As the demand for photovoltaics rapidly increases, there is a pressing need for the identification of new visible light absorbing materials for thin-film solar cells that offer similar performance to the current technologies based on CdTe and Cu(In,Ga)Se 2 . Metal sulphides are the ideal candidate materials, but their band gaps are usually too large to absorb significant fractions of visible light. However, by combining Cu + (low binding energy d 10 band) and Sb 3+ /Bi 3+ (low binding energy s 2 band), the ternary sulphides CuSbS 2 and CuBiS 2 are formed, which have been gathering recent interest for solar cell applications. Using a hybrid density functional theory approach, we calculate the structural and electronic properties of these two materials. Our results highlight the stereochemical activity of the Sb and Bi lone pair electrons, and predict that the formation of hole carriers will occur in the Cu d 10 band and hence will involve oxidation of Cu(I).
Journal of Materials Chemistry, 2010
Article Title: Protonic defects and water incorporation in Si and Gebased apatite ionic conductor... more Article Title: Protonic defects and water incorporation in Si and Gebased apatite ionic conductors Year of publication: 2010 Link to published article: http://dx.
One of the key factors behind the rapid evolution of molecular spintronics is the efficient reali... more One of the key factors behind the rapid evolution of molecular spintronics is the efficient realization of spin manipulation of organic molecules with a magnetic center. The spin state of such molecules may depend crucially on the interaction with the substrate on which they are adsorbed. In this letter, we demonstrate, using ab initio density functional calculations, that the stabilization of a high spin state of an iron porphyrin (FeP) molecule can be achieved via a dedicated chemisorption on magnetic substrates of different species and orientations. It is shown that the strong covalent interaction with the substrate increases Fe-N bond lengths in FeP and hence a switching to a high spin state (S=2) from a low spin state (S=1) is achieved. A ferromagnetic exchange interaction is established through a direct exchange between Fe and substrate magnetic atoms as well as through an indirect exchange via the N atoms in FeP. The mechanism of exchange interaction is further analyzed by considering structural models constructed from ab initio calculations. Finally, we illustrate the possibility of detecting a change in the molecular spin state by x-ray magnetic circular dichroism, Raman spectroscopy and spin-polarized scanning tunneling microscopy.
Ab initio calculations of electronic structure of anatase TiO 2
Chinese Physics, 2004
Applied Parallel Computing. State of the Art in Scientific Computing
... 871 Dries Kimpe, Andrea Lani, Tiago Quintino, Stefan Vandewalle, Stefaan Poedts, and Herman D... more ... 871 Dries Kimpe, Andrea Lani, Tiago Quintino, Stefan Vandewalle, Stefaan Poedts, and Herman Deconinck Epitaxial Surface Growth with Local Interaction ... 1016 Margreet Nool, Erik Jan Lingen, Aukje de Boer, and Hester Bijl Algorithms and Applications for Blue Gene/L New ...
Synthesis, conductivity and structural aspects of Nd3Zr2Li7-3xAlxO12
Journal of Materials Chemistry a, 2013
ABSTRACT In this paper we report the synthesis, structure and Li ion conductivity of a new tetrag... more ABSTRACT In this paper we report the synthesis, structure and Li ion conductivity of a new tetragonal garnet phase Nd3Zr2Li7O12. In line with other tetragonal garnet systems, the Li is shown to be ordered in the tetrahedral and distorted octahedral sites, and the Li ion conductivity is consequently low. In an effort to improve the ionic conductivity of the parent material, we have also investigated Al doping to reduce the Li content, Nd3Zr2Li5.5Al0.5O12, and hence introduce disorder on the Li sublattice. This was found to be successful leading to a change in the unit cell symmetry from tetragonal to cubic, and an enhanced Li ion conductivity. Neutron diffraction studies showed that the Al was introduced onto the ideal tetrahedral garnet site, a site preference also supported by the results of computer modelling studies. The effect of moisture on the conductivity of these systems was also examined, showing significant changes at low temperatures consistent with a protonic contribution in humid atmospheres. In line with these observations, computational modelling suggests favourable exchange energy for the Li+/H+ exchange process.
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Papers by Pooja Panchmatia