Using quantum mechanical calculations, a research team at the University of Houston has demonstrated that a graphene sheet can be converted into a piezoelectric material by producing holes in a specific pattern onto it.
Piezoelectric materials can produce electricity when physical pressure is applied and vice versa. These materials find use in a broad array of applications, including energy harvesting and to make artificial muscles and ultrasensitive sensors.
By nature, graphene is not a piezoelectric material. However, according to the University of Houston researchers, any type of graphene, whether it is insulator or semiconducting, can be made to behave like a piezoelectric material by creating triangular-shaped holes on its surface followed by the application of a consistent pressure.
Based on the research team’s quantum mechanical calculations, graphene’s piezoelectric behavior was induced by the triangular holes. The team did not observe the piezoelectric behavior in graphene when it created circular holes in the material. It also discovered that the pseudo-piezoelectricity of graphene was as high as that of familiar piezoelectric materials such as quartz.
According to the researchers, triangle-shaped holes can be punched in real graphene in a laboratory utilizing electron-beam radiation. Hence, these quantum mechanical calculations can be tested, utilizing current methods. The American Institute of Physics’ journal, Applied Physics Letters has accepted the paper that describes the findings of the researchers. In the paper, the researchers stated that the inclusion of graphene to the list of efficient electromechanical substances that demonstrate piezoelectricity opens door for new opportunities for both graphene and for piezoelectricity-based applications.
Source: http://www.aip.org