A little addition of Cl to MAPbI 3 has been reported to improve the material stability as well as light harvesting and carrier conducting properties of organometal trihalide perovskites, the key component of perovskite solar cell (PSC). However, the mechanism of performance enhancement of PSC by Cl addition is still unclear. Here, we apply the efficient virtual crystal approximation method to revealing the effects of Cl addition on the structural, electronic, optical properties and material stability of MAPb(I 1-x Cl x ) 3 . Our ab initio calculations present that as the increase of Cl content cubic lattice constants and static dielectric constants decrease linearly, while band gaps and exciton binding energies increase quadratically. Moreover, we find the minimum of exciton binding energy at the Cl content of 7%, at which the chemical decomposition reaction changes coincidentally to be from exothermic to endothermic. Interactions among constituents of compound and electronic charge transferring during formation are carefully discussed. This reveals new prospects for understanding and designing of stable, high efficiency PSCs.

The structures of some bisphosphonates (clodronate, etidronate, pamidronate, alendronate, risedronate, zoledronate, minodronate) were obtained and analyzed, and their adsorption energies onto hydroxyapatite (001) surface were compared to find out ranking order of binding affinity, which shows that the adsorption energy is the largest for pamidronate, followed by alendronate, zoledronate, clodronate, ibandronate, the lowest for minodronate and etidronate.

Monomolecular drug carriers based on calix[n]-arenes and -resorcinarenes containing the interior cavity can enhance the affinity and specificity of the osteoporosis inhibitor drug zoledronate (ZOD). In this work we investigate the suitability of nine different calix[4]-arenes and -resorcinarenes based macrocycles as hosts for the ZOD guest molecule by conducting ab initio density functional theory calculations for structures and energetics of eighteen different host-guest complexes. For the optimized molecular structures of the free, phosphonated, sulfonated calix[4]-arenes and -resorcinarenes, the geometric sizes of their interior cavities are measured and compared with those of the host-guest complexes in order to check the appropriateness for host-guest complex formation. Our calculations of binding energies indicate that in gaseous states some of the complexes might be unstable but in aqueous states almost

We report a computational study of the adsorption of zoledronic acid molecule on hydroxyapatite (001) surface within ab initio density functional theory. The systematic study has been performed, from hydroxyapatite bulk and surface, and zoledronic acid molecule to the adsorption of the molecule on the surface. The optimized bond lengths and bond angles were obtained and analyzed, giving an evidence of structural similarity between subjects under study. The formation energies of hydroxyapatite (001) surfaces with two kinds of terminations were computed as about 1.2 and 1.5 J/m 2 with detailed atomistic structural information. We determined the adsorption energies of zoledronic acid molecule on the surfaces, which are -260 kJ/mol at 0.25 ML and -400 kJ/mol at 0.5 ML. An atomistic insight of strong binding affinity of zoledronic acid to the hydroxyapatite surface was given and discussed.

In this paper, we study the electroosmotic transport in a nanofluidic channel by using a mean-field theory accounting for non-uniform size effect and solvent polarization effect. We witness that in the presence of the given zeta potential, an enhancement of ion size invariably lowers the electroosmotic velocity, thereby increasing the magnitude of electrostatic potential, irrespective of considering solvent polarization. It is also proved that solvent polarization allows both the magnitude of electrostatic potential and the electroosmotic velocities to decrease. In addition, we find that increasing zeta potential augments not only ion size effect but also solvent polarization effect. Furthermore, we demonstrate that decreasing bulk ion number density causes an increase in electroosmotic velocity at the centerline. We compare the properties of aqueous electrolytes with those of the electrolytes where solvent is ethylalcohol. Finally, we study how solvent polarization and ionic size affect streaming potential and electroviscous effect. It is emphasized that the present study can provide a good way to control the nanofluidic transport for a plethora of biological and industrial applications.

Using density functional theory calculations, we have investigated the interlayer cation exchange phenomena in muscovite mica, which is motivated by a necessity to develop flexible high-insulating covering materials. The crystalline structures, chemical bonding properties, energetics, and electronic properties of muscovites before and after exchange of interlayer K + cation with ammonium (NH + 4 ) or methylammonium (CH 3 NH + 3 ) ion were calculated. It was found that the unit cell volume changes are negligibly small upon exchange with NH + 4 ion, while the unit cells are expanded with about 4 % relative rate when replacing the interlayer K + cation with CH 3 NH + 3 ion. The energy band gap of pre-exchanged muscovite was calculated to be about 5 eV, which hardly changes upon interlayer cation exchange with either NH + 4 or CH 3 NH + 3 ion, indicating the preservation of high insulating property of muscovite. The exchange energies were found to be about -100 kJ/mol for NH + 4 and about -50 kJ/mol for CH 3 NH + 3 exchange, indicating that the exchange reactions are exothermic. A detailed analysis of atomic resolved den-Korea sity of states and electron density redistribution was provided.

We theoretically study the size effect of water molecule clusters not only on electrostatic interaction between two charged surfaces in an aqueous electrolyte but also on electroosmotic transport in a nanofluidic channel. Applying a free energy based mean-field approach accounting for different sizes of ions and water molecule clusters, we derive a set of coupled equations to compute electrostatic and electroosmotic properties between charged surfaces. We verify that the smaller the size of a water cluster, the stronger the electroosmotic transport in nanofluidic channels. In addition, we find that an increase in size of a water cluster yields a decrease in electrostatic interaction strength between similar or oppositely charged planar surfaces.

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