Enhancing pyroelectric performance with an electrically-controlled thermal switch

While photovoltaic cells have had widespread success in converting solar energy to electrical energy, their efficiency diminishes when operating at high temperatures, limiting their suitability for high-power applications. In contrast, pyroelectric materials offer distinct advantages in such scenarios; their efficiency is enhanced under elevated temperatures, creating the best candidates for energy conversion applications. However, a continuous output from the pyroelectric device requires efficient, fast heating and cooling cycles. Here, we report a tunable thermal switch with high reflectance modulation to increase pyroelectric materials’ performance. The thermal switch comprises a thin-film stack of ITO/WO₃/Ta₂O₅/NiO/Au on glass substrate. The layers’ thicknesses are optimized for higher reflectance modulation, fast response time, and lower power dissipation. We achieved reflectance modulation of 60% (79% to 19%), with a coloration time of 7.8 seconds and a bleaching time of 3.5 seconds. Coupling this thermal switch with the pyroelectric (550-µm-thick PZT) material’s heating/cooling processes, the energy density output increased significantly (~89%) in comparison to a device lacking such tunability.