A facile synthesis of segmented silver nanowires and enhancement of the performance of polymer solar cells.

In this work, segmented silver nanowires (AgNWs) with an average diameter of 60 nm have been successfully synthesized by a typical polyol method without any templates and seeds. The synthesized segmented AgNWs were strongly dependent on the reaction temperature and time. It was found from high-resolution transmission electron microscopy and selected area electron diffraction measurements that the connection node of segmented AgNWs was in the form of a twinned crystal. We speculated that these segmented AgNWs were possibly derived from end-to-end self-connection and self-concrescence of two neighbouring Ag nanorods or nanowires at a suitable reaction temperature and time, which is further confirmed by the secondary growth of AgNWs. In addition, segmented AgNWs were blended into hole transporting layers to enhance the performance of polymer solar cells (PSCs) by utilizing their localized surface plasmon resonance and optical scattering effects. As a result, the power conversion efficiency (PCE) and short-circuit current density (Jsc) of PSCs with segmented AgNWs increased from 2.81% and 8.99 mA cm-2 to 3.30% and 9.95 mA cm-2, respectively.

Ab initio calculations on potential energy curves and radiative lifetimes for the band systems A(2)Π-X(2)Σ(+) of magnesium monohalides MgX (X=F, Cl, Br, I).

Ab initio calculations on potential energy curves (PECs), spectroscopic constants, transition dipole moments, radiative transition probabilities and lifetimes for the ground state (X(2)Σ(+)) and the first excited state (A(2)Π) of MgX (X=F, Cl, Br, I) molecules are determined by high-level internally contracted multi-reference configuration interaction (ic-MRCI) method. In order to improve the calculation, the Davidson modification (+Q) and scalar relativistic correction are included. The present results show that most of spectroscopic constants are in accordance with the measurements, the equilibrium internuclear distance Re increases while the other spectroscopic constants reduce along with the increasing of the atomic number of the halogen from F to I. Diagonal vibrational transitions are found to be dominant for the A(2)Π→X(2)Σ(+) system of MgX molecules. The corresponding radiative lifetimes of ν'=0 are computed to be 7.24, 9.98, 18.94 and 22.72 ns for MgF, MgCl, MgBr, and MgI, respectively. The calculated result of MgF molecule is in good agreement with the recent theoretical result of 7.16 ns, with a small relative error percent of 1.11%.