Chapter 16 -- Energy harvesting from solar energy using nanoscale pyroelectric effects

Abstract

A comprehensive theoretical analysis of a dynamic thermo-ferro-electric pre-stressed bimorph energy harvester is performed. This analysis takes into account pyroelectric and thermal expansion effects. The most general analytical expression for the energy conversion coefficients are presented for a bilayer. These coefficients are derived for a more general situation when mechanical, electrical, and thermal fields are present. We also derive coefficients (transformation coefficients) for sensing, actuating, and energy harvesting. For a particular case, we develop an analytical expression for the energy-harvesting coefficient due to pyroelectric and thermal expansion effects in a rather general situation. This is a function of material properties, location of boundary conditions, vibration frequency, and in-plane compressive/tensile follower force. Numerical simulations of the analytical results are presented in detail. The effects of volume fraction, material properties, applied mechanical loads, and boundary conditions on the harvesting coefficients are introduced in the system. The results for a cantilever and a simply supported beam are obtained as particular cases. The result for a low-frequency (static) system is obtained as a particular case by approaching the vibration frequency to zero. It is shown that volume fraction, material properties, plain compressive/tensile follower force, location of the boundary conditions, and vibrational frequency of the bimorph strongly influence the strain distribution, and this in effect influences the charge coefficient and the generation of energy. The proposed model can be extended to thermal energy harvesters with piezoelectric-shape memory alloy (SMA) composites, nanomaterials, and nanocomposites for solar energy conversion.