The multi-functionality of lead magnesium niobate-lead titanate/paint (PMN-PT/paint) nanocomposite films for energy harvesting via piezoelectric and pyroelectric effects is described. PMN-PT/paint films have been fabricated by a conventional paint-brushing technique to provide a low-cost, low-temperature and low–energy route to create multi-functional films. The properties investigated included dielectric constants, ε’ and ε”, as a function of temperature, frequency and composition. From these parameters, it is indicated that the dielectric constants and AC conductivity (σAC) increase with an increase of filler content and temperature, implying an improvement of the functionality of the films. The results revealed that σAC obeyed the relation σAC = Aωs, and exponent s, was found to decrease by increasing the temperature. The correlated barrier hopping was the dominant conduction mechanism in the nanocomposite films. The efforts were made to investigate the performance of nanocomposite films to mechanical vibrations and thermal variations. A cantilever system was designed and examined to assess its performance as energy harvesters. The highest output voltage and power for a PMN-PT/paint based harvester with a broad frequency response operating in the -31-piezoelectric mode were 65 mV and 1 nW, respectively. Voltage and power were shown to be enhanced by application of thermal variations. Thus, films could be utilized for combined energy harvesting via piezoelectric and pyroelectric characteristics.
Available online 1 March 2018