Pyroelectric Nanogeneratorsfor Harvesting ThermoelectricEnergy.

Harvesting thermoelectric energy mainly relies on theSeebeck effectthat utilizes a temperature difference between two ends of the devicefor driving the diffusion of charge carriers. However, in an environmentthat the temperature is spatially uniform without a gradient, thepyroelectric effect has to be the choice, which is based on the spontaneouspolarization in certain anisotropic solids due to a time-dependenttemperature variation. Using this effect, we experimentally demonstratethe first application of pyroelectric ZnO nanowire arrays for convertingheat energy into electricity. The coupling of the pyroelectric andsemiconducting properties in ZnO creates a polarization electric fieldand charge separation along the ZnO nanowire as a result of the time-dependentchange in temperature. The fabricated nanogenerator has a good stability,and the characteristic coefficient of heat flow conversion into electricityis estimated to be ∼0.05–0.08 Vm2/W. Ourstudy has the potential of using pyroelectric nanowires to convertwasted energy into electricity for powering nanodevices. [ABSTRACT FROM AUTHOR]