Research

Currently, the research program involves two directions:

1. Thermoelectric phases

Thermoelectric materials can convert heat into electricity (Seebeck effect, figure on the right) or perform cooling/heating when electrical current is passed through them (Peltier effect). Thermoelectric materials are used to generate electricity when other source of electricity are not available (i.e. deep space missions) or to convert waste heat into electricity thus reducing fuel consumption (i.e. in cars). They are also used to perform cooling when other cooling techniques cannot be easily applied (i.e. car seats, spot cooling in electronics).
One of the challenges in the thermoelectric research is to reduce thermal conductivity of materials in order to optimize their performance.

Our group tackles this challenge by utilizing a number of approaches: band engineering, doping, phonon scattering. We target both charge and phonon transport properties to obain a material known as "phonon-glass electron-crystal". We also prepare unique suboxide phases, in which a band gap is opened in the original semimetallic material through the incorporation of oxide fragments.

2. Phosphor materials

Phosphor materials are used for lighting applications (LEDs), where they downconvert the high-energy blue radiation into lower energy one (yellow, green and red) to yield the white light. We explore Cr³⁺ and Mn⁴⁺ phosphors that emit the red light and can be employed for LEDs.

We also explore Cr³⁺ and Mn⁴⁺ phosphors for temperature sensing. The life time of the Cr³⁺ and Mn⁴⁺ emission is temperature dependent and can be correlated to the temparature.

Resources