Inspired by the concept of multilayer thermionic devices, the team designed a solid-state thermionic device using van der Waals (vdW) heterostructure sandwiched between two graphene electrodes, to achieve high energy conversion efficiency in the temperature range of 400 to 500 K. The technology enables performance (8% above) of devices comparable to or even better than state-of-art thermoelectric devices around room temperature. This novel design may boost interest in thermionic emission-based energy conversion and pave the way towards another alternative to solutions to low-grade waste heat harvesting.
The researchers state that this design is the first in combining the advantages of graphene electrodes and TMDs to function as a thermionic-based device. In January 2017, researchers at Stanford University demonstrated a graphene-based high efficiency thermal-to-electricity conversion technology, called thermionic energy convertor. By using graphene as the anode, the efficiency of the device is increased by a factor of 6.7 compared with a traditional tungsten anode.