By merely by punching triangular holes in a semiconducting or insulator form of graphene, engineers at the University of Houston calculate they can coax graphene into behaving like a piezoelectric material.

Piezoelectric substances generate electricity in response to physical pressure, and vice versa, and scientists can use these materials for applications such as energy harvesting and artificial muscles, as well as to make precise sensors.

Ref.: Swapnil Chandratre and Pradeep Sharma, Coaxing graphene to be piezoelectric, Applied Physics Letters, 2012; (in press)