A research team has created molecules with a three-dimensional shape and an internal twist. These molecules exhibit the properties of organic semiconductors.
Key findings
1. Creating twisted molecules:
– The team introduced methyl groups into a planar molecule containing several thiophene units, forcing it into a twisted conformation.
– This created a solid-state structure in which electricity can flow three-dimensionally.
2. Verification of properties:
– The molecule was tested in an organic field-effect transistor, acting as an organic semiconductor.
– This paves the way for next-generation electronic devices.
3. Publication of results:
– The results were published online in Chemical Communications.
Potential applications
Electronic devices based on organic materials are lightweight, flexible, and can display a wide variety of properties by subtle changes in molecular structure, making them promising environmentally friendly next-generation devices.
Most organic electronic materials developed to date are made of planar molecules, so charge transport is confined to limited directions. As a result, devices require strict control of molecular orientation.
The researchers wondered whether “twisting” molecules could yield a new material architecture in which charge carriers move easily in three dimensions.
Methodology
The team attached methyl groups to molecules containing multiple thiophene units, synthesizing twisted molecules.
X-ray crystallography confirmed the twisted geometry and revealed that, in the solid state, the molecules stack in a three-dimensional fashion. Computational analysis of charge-transport pathways predicted an aggregated structure in which holes can migrate in several directions.
When the molecule was fabricated into an organic field-effect transistor, it exhibited a hole mobility of $1.85 × 10^{-4}$ $cm^2 V^{-1} s^{-1}$, experimentally confirming its behavior as an organic semiconductor.
Conclusion
This work offers a new perspective on designing organic electronic materials: in addition to flat molecules, twisted molecules can also be exploited. The strategy may solve the long-standing problem of orientation control in devices. The findings are expected to spur the development of higher-performance organic semiconductors that employ such three-dimensional molecular architectures.
Provided by: National Institutes of Natural Sciences.