A team of researchers working at the Worcester Polytechnic Institute (WPI) recently developed a hi-tech, light activated semiconductor nanocomposite material that has applications in multiple segments like grippers for a surgical robot, microscopic actuators, light activated micro-mirrors for all kind of optical telecommunication systems, and highly efficient photodetectors and solar cells.

 

 

 

As Balaji Panchapakesan, the associate professor at the mechanical engineering department of this university adds, “This is a new area of science. Very few materials are able to convert photons directly into mechanical motion. In this paper, we present the first semiconductor nanocomposite material known to do so. It is a fascinating material that is also distinguished by its high strength and its enhanced optical absorption when placed under mechanical stress. Tiny grippers and actuators made with this material could be used on Mars rovers to capture fine dust particles. They could travel through the bloodstream on tiny robots to capture cancer cells or take minute tissue samples. The material could be used to make micro-actuators for rotating mirrors in optical telecommunications systems; they would operate strictly with light, and would require no other power source.” 

 

Just like the other semiconductor materials, (say molybdenum disulfide) this material features the electron arrangement  that keeps moving its atoms. Specifically, these electrons are capable of moving in groups in the external most orbits of atoms called valence bands and are capable of moving to other orbital group called conduction band. However, this takes place only when these electrons get stimulated by an energy feed like a beam of photons of light or an electromagnetic field. By crossing this band gap the stream of electrons lead to the generation of electricity flow that makes their installation in computer chips and solar cells possible. When the negatively-charged electrons go to-and-fro between orbitals, these leave behind voids of positive charge  called holes. The pair of electron hole and bound electron are known as exciton.