Implication of Molecular Weight on Optical and Charge Transport Anisotropy in PQT-C12 Films Fabricated by Dynamic FTM.

Large area (>20 cm × 2 cm)-oriented thin films of PQT-C12 with varying molecular weight and polydispersity index (PDI) were fabricated by the ribbon-shaped floating film transfer method aiming toward their application as an active semiconductor element of organic field effect transistors (OFETs). Investigation on the influence of the molecular weight and PDI upon the extent of molecular alignment and anisotropic charge transport was systematically carried out. It has been demonstrated that high molecular weight in combination with low PDI not only leads to a very high optical anisotropy >10 but also high charge carrier anisotropy with a hole mobility of about 0.

Passivation of Grain Boundary by Squaraine Zwitterions for Defect Passivation and Efficient Perovskite Solar Cells.

Unavoidable defects in grain boundaries (GBs) are detrimental and critically influence the organometal halide perovskite performance and stability. To address this issue, semiconducting molecules have been employed to passivate traps along perovskite GBs. Here, we designed and synthesized three squaraine molecules (SQ) with zwitterionic structure to interact with under-coordinated Pb and passivate Pb-I antisite defects.