First-Principles Study of Structural, Electronic and Magnetic Properties of Metal-Centered Tetrahexahedral V15+ Cluster

Abstract

The V-centered bicapped hexagonal antiprism structure (A), as the most stable geometry of the cationic V15+ cluster, is determined by using infrared multiple photo dissociation (IR-MPD) in combination with density functional theory computations. It is found that the A structure can be stabilized by 18 delocalized 3c-2e σ-bonds on outer V3 triangles of the bicapped hexagonal antiprism surface and 12 delocalized 4c-2e σ-bonds on inner trigonal pyramidal V4 moiety, and the features are related to the strong p-d hybridization of the cluster. The total magnetic moments on the cluster are predicted to be 2.0 µB, which come mainly from the central vanadium atom.

Thionation Enhances the Performance of Polymeric Dopant‐Free Hole‐Transporting Materials for Perovskite Solar Cells

“…Solution processable diketopyrrolopyrrole (DPP) based polymers display high charge carrier mobility ranging from 0.1 to 10 cm 2 V −1 s −1 , because of the strong π–π stacking between the conjugated backbones . They have been widely used in organic field‐effect transistors (OFETs) and organic photovoltaics (OPVs), and they could be ideal candidates when aiming at cheaper dopant‐free polymeric HTMs for PSCs. However, while their energy levels are well aligned with the valence band (VB) and conduction band (CB) of perovskite, only few examples of DPP‐based PSCs have been reported in the literature and their efficiency remains modest .…”