Large pyroelectric current generation induced by droplet cooling

This paper demonstrates an alternative and simple approach for achieving a fast temperature change on a pyroelectric system through droplet cooling, which leads to enhancement in pyroelectric current generation. The pyroelectric system was composed of a pyroelectric layer of lithium tantalate (LiTaO₃) that was sandwiched between two layers of gold/titanium (Au/Ti) as the top and bottom electrodes. Due to both high latent heat and sensible heat of water, there was a rapid heat exchange during the droplet cooling process, and the pyroelectric layer underwent a fast temperature change with the maximum rate of ∼725 ​°C/s. The induced pyroelectric current density reached as high as ∼8.8 ​μA/cm². Such pyro-current density is among the highest reported so far. The pyroelectric response was also investigated by using the surfaces with different wettability. The hydrophilic surfaces underwent faster heat dissipation, leading to the generation of larger current than that of the hydrophobic surfaces during the droplet cooling process. This work may help expand the utilization of pyroelectric materials in various applications that involve the current generation using pyroelectric effect.