Quadrites and Crossed-Chain Crystal Structures in Polymer Semiconductors

Many high-performance conjugated
polymers for organic photovoltaics
and transistors crystallize such that chains are parallel, resulting
in significant anisotropy of the nanoscale charge transport properties.
Here we demonstrate an unusual intercrystallite relationship where
thin lamellae adopt a preferred epitaxial relationship with crossed-chains
at the interface. The crossed-chains may allow either crystal to use
the other as an “electronic shunt”, creating efficient
quasi-three-dimensional transport pathways that reduce the severity
of grain boundaries and defects in limiting transport.

诸多用于有机光伏（organic photovoltaics）与晶体管的高性能共轭聚合物（conjugated polymers）会以链段平行的方式结晶，进而使纳米级电荷传输特性呈现出显著的各向异性。本研究揭示了一种罕见的晶间关系（intercrystallite relationship）：薄层片晶（lamellae）在界面处与交叉链（crossed-chains）形成择优外延关系（epitaxial relationship）。该交叉链可使两种晶体互为“电子分流（electronic shunt）”介质，从而构建出高效的准三维传输路径，削弱了晶界（grain boundaries）与缺陷对电荷传输的限制作用。