Profs. Ke-Li Han and Wei-Qiao Deng from the State Key Laboratory of Molecular Reaction Dynamics at Dalian Institute of Chemical Physics just published new results predicting the charge carrier mobilities of π-stacked systems, which are used in electric devices. The research paper titled “Quantitative prediction of charge mobilities of π-stacked systems by first-principles simulation” was published in Nature Protocols (2015, Volume 10, Pages 632–642).
π-stacked systems are an important feature in organic semiconductors, liquid crystals, and even in DNA. The presence of strong intermolecular π-π coupling effects in π-stacked systems facilitates charge transfer between adjacent molecules. This feature of π-stacked systems makes them very useful in electric devices, such as organic field-effect transistors and DNA molecular wires. Unlike traditional inorganic semiconductors, charge transfer in organic π-stacked systems behaves in such a way that conventional semiconductor theory approach cannot be used to explain charge migration. Moreover, due to the diversity of organic molecules, there are many possibilities for structures of π-stacked systems. The critical issue thus becomes how to create a material that has required properties and functions. New theoretical approaches to predict charge transfer in π-stacked systems thus are an important way to explore the properties of myriad molecular structures without having to synthesize them.
In 2009, Profs. Han and Deng developed a theoretical approach combining Marcus theory and quantum chemistry calculations that could accurately predict the anisotropic charge mobilities in organic semiconductors (J. Phys. Chem. B 2009, 113, 8614). Through many years of development, they have gradually refined their approach and successfully used it to study a series of organic semiconductor materials (Chem. Commun. 2010,46,5133; Phys. Chem. Chem. Phys., 2010, 12, 9267). In this newest article, a computational approach was developed to predict the charge mobility using only a crystal structure of π-stacked systems. The theoretical results obtained coincide well with experiments.
These newly published results are important in that they bring new insight to the organic electronics field by establishing a basis for large-scale screening of π-stacked systems.
This work is financially supported by National Natural Science Foundation of China and the Basic Research Program of China (973 Project). (By Lei Sun)
DALIAN INSTITUTE OF CHEMICAL PHYSICS, CHINESE ACADEMY OF SCIENCES