•Adsorption of [PbCl]+ on the kaolinite(0 0 1) surface was first investigated by DFT.•A water environment was considered for species of [PbCl]+ and adsorption complex.•Binding energy was calculated based on the deprotonation of surface OH group.•Complex structure, preferred adsorption position and adsorption type were solved.•Antibonding state filling was found involved in the PbO (or Cl) interaction.Adsorption of [PbCl]+ on the basal hydroxylated (0 0 1) surface of kaolinite in aqueous system was investigated by the plane-wave pseudopotential density functional theory calculations. Structures of the adsorption complexes including the coordination geometry and effective coordination number on the two different types of surface sites were examined, with the PbO (or Cl) bonding mechanism explored. [PbCl]+ prefers to bind with the hydroxylated kaolinite(0 0 1) surface in monodentate way on the site of Ou in “upright” hydroxyl. Complexation of [PbCl]+ in bidentate way on OuOl (oxygen of “lying” hydroxyl) site of single Al center is also probable. All adsorption complexes feature coordination number of 3–5 within the hemidirected geometry. Charge transfer occurs with ligating atoms of oxygen denoting some electrons to Pb(II) and Cl. Upon the partial density of states (PDOS) projections and Mulliken bond populations, both bonding and antibonding state filling are involved in the PbO (or Cl) interaction. Pb 6p interacting with the antibonding combination of Pb 6s and O 2p states is the dominant orbital contribution of Pb(II) with surface oxygen, while the bonding Pb 6sCl 3p state filling is primarily responsible for the PbCl interaction.

Calculations have been made regarding the strong electron-withdrawing cyano (−CN) group, which was introduced onto the backbone of poly(3-hexylthiophene) (P3HT), as an effective way to improve the parameters essential for the photovoltaic performance of organic solar cells (OSCs). The substitution effect on the optical and photovoltaic properties of various CN-substituted P3HT are comprehensively investigated by means of density functional theory and molecular dynamics simulation. The results of theoretical modeling indicate that the direct introduction of strong electron-withdrawing group −CN onto the backbone of P3HT, can not only significantly reduce the HOMO level of polymer which leads to increased open circuit voltage (VOC) in solar cells, but also exhibit red-shifted absorption spectra and increased hole mobility, which might lead to the enhancement of the short circuit current (JSC) and the fill factor (FF) in comparison to pristine P3HT and fluorine (F)-substituted P3HT. These results provide a fundamental understanding of how different electron-withdrawing groups influence the photophysical, electrochemical, and optoelectronic properties of conjugated polymers and potentially provide useful information for better design strategy for OSCs.