Transport in Twisted Crystalline Charge Transfer Complexes

Yongfan Yang, Yuze Zhang, Chunhua T. Hu, Mengmeng Sun, Sehee Jeong, Stephanie S. Lee, Alexander G. Shtukenberg, Bart Kahr

Research output: Contribution to journalArticlepeer-review


Many crystals grow as banded spherulites from the melt with an optical rhythm indicative of helicoidal twisting. In this work, 23 of 41 charge transfer complexes (CTCs) are grown with twisted morphologies. As a group, CTCs more commonly twist (56%) than molecular crystals arbitrarily chosen in our previous research (31%). To analyze the effect of twisting on charge transport, three tetracyanoethylene-based CTCs with phenanthrene (PhT), pyrene (PyT), and perylene are characterized. PhT and PyT are subject to mobility measurements using organic field-effect transistors. The mobilities for twisted crystals are around three times higher than for crystals with no ostensible optical modulation, which are effectively straight. The differences in mobilities of straight and twisted crystals are considered computationally based on density functional theory. Straight crystal models built from crystallographic information files are calculated and present anisotropic hole and electron transport. For twisted crystal models, adjacent layers in the supercell are rotated by 0.01° around experimentally determined twisting directions. The modified transfer integrals lead to a slight increase (up to 25%) in the calculated mobilities of twisted crystals. Comparisons of model calculations on individual fibrils and measurements of ensembles of fibrils indicate that interfaces between single crystals are likely consequential.

Original languageEnglish (US)
Pages (from-to)1778-1788
Number of pages11
JournalChemistry of Materials
Issue number4
StatePublished - Feb 22 2022

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Materials Chemistry


Dive into the research topics of 'Transport in Twisted Crystalline Charge Transfer Complexes'. Together they form a unique fingerprint.

Cite this