Jun 20, 2012
Feeling the heat of pyroelectricity
Engineered pyroelectric materials represent a powerful approach to innovative applications in areas such as renewable energy and the development of new sensor/detector technologies. Yet compared with their thermoelectric counterparts, pyroelectric materials have received substantially less attention. While thermoelectric materials require thermal gradients, pyroelectrics convert heat to electrical current using dynamic variations in temperature. This imparts a strong potential for harvesting energy from recurrent thermal cycles in the environment. In order to move from fundamental studies towards technological applications of pyroelectric materials and devices, it is necessary to have the ability to characterize their properties with increased sensitivity, precision and flexibility.
Through a straightforward modification to a commercially available atomic force microscope, researchers at the California NanoSystems Institute's Nano and Pico Characterization Laboratory (NPC) have demonstrated a method for characterizing the induced pyroelectric effect and resultant polarization distribution with nanoscale precision that is broadly available for any research laboratory. Using a combination of electrostatic force microscopy (EFM) and thermal cycling, this approach combines precise control over the relevant parameters that define the pyroelectric effect with real-space imaging at nanoscale resolution.
Sensors and personal electronics
Validation of the technique on what would generally be considered a challenging sample (naturally occurring tourmaline gemstones) shows the capabilities of this straightforward approach for the design, fabrication and characterization of a broad class of pyroelectric devices, regardless of their size and shape. In addition, the reported results indicate a possibility to turn natural thermal cycles, including the ones that originate in ambient/turbulent air convection, into energy sources for small electronic devices, such as environmental sensors and personal electronics.
The researchers presented their results in the journal Nanotechnology.
About the author
The team, led by nanoscience pioneer Prof. James Gimzewski, consists of postdoctoral scholar and Madame Curie Fellow Dr Cristina Martin-Olmos along with the scientific director of the NPC Lab, Dr Adam Stieg. The researchers carried out this work in the NPC Core Laboratory at CNSI-UCLA, a shared user facility that provides access to state-of-the-art microscopic techniques to visualize surfaces, adsorbates, nanostructures and devices at the atomic and molecular scale under a wide range of experimental conditions using scanning probe microscopy. More information about the team and the NPC Laboratory at CNSI can be found at http://nanopicolab.cnsi.ucla.edu>.