Non-linear dielectric materials are crystalline solids having internal electric fields created spontaneously. The internal electric fields can be altered non-linearly by applying external electric fields. These materials are electrical insulators implemented in computer memories, detectors of light, heat and pressure.
Pyroelectric materials are crystalline solids having internal electric dipoles oriented towards a specific direction. An exposure of these materials into a temperature change results in fluctuations of the electric dipoles and a change of their surface electric charge density which can be monitored as electric current. These materials are implemented in highly sensitive detectors of light (especially infra-red) and heat.
Piezoelectric materials are crystalline solids capable of changing their elastic strains due to applied electric fields and creating electric charges due to applied mechanical forces. This behavior is associated with a change of length and formation of electric dipoles in ionic-covalent chemical bonds. These materials are implemented in miniaturized motors, detectors of mechanical force and miniaturized electric power generators by mechanical force harvesting.
Photovoltaic materials translate the absorption of light into an electrical current with no applied external electrical filed. The process involves the absorptions of light in the visible region and the generation of free carrier that can then be harvested at the electrodes. A variety of soft and hard materials have shown promise for photovoltaic applications including crystalline and amorphous semiconductors, conjugated polymers and organic/inorganic hybrids.
Electroluminescent materials emit light under an applied bias and compose the active layer of light emitting diodes (LEDs). Under the applied bias charges are injected into the electroluminescent material and upon their recombination light could be emitted. The color emitted is an intrinsic property of the electroluminescent material. A variety of fluorescent materials are used for LEDs including crystalline semiconducting thin films and quantum dots, conjugated polymers and small-molecule organic thin films.
Specific research activities in the field of functional materials can be found via the following faculty: