Multifunctional flexible ferroelectric thick-film structures with energy storage, piezoelectric and electrocaloric performanceŠadl, Matej (Avtor) Prah, Uroš (Avtor) Kovacova, Veronika (Avtor) Defay, Emmanuel (Avtor) Rojac, Tadej (Avtor) Lebar, Andrej (Avtor) Valentinčič, Joško (Avtor) Uršič Nemevšek, Hana (Avtor) energy managementenergy self-sufficiencyAs a major challenge, sustainable energy management and energy self-sufficiency require microsystems that manage multiple energy operations in a single device. In this work, flexible thick-film structures with promising energy storage and electrocaloric cooling capabilities as well as piezoelectric properties are developed. The functional thick-film layer is based on relaxor-ferroelectric 0.65Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$– 0.35PbTiO$_3$ (PMN–35PT) directly deposited on a flexible polyimide substrate by an aerosol deposition method. The thick-film structures exhibit a promising recoverable energy-storage density of 10.3 J cm$^{–3}$. After extensive bending tests, the structures showed no signs of degradation. The high bendability and durability are confirmed by stable energy storage properties after bending up to a radius of 1.5 mm (2.4% bending strain) and 10$^5$ repeated bending cycles. The developed thick-film structures also exhibit a piezoelectric coefficient d$_{33}$ of ∼80 pm V$^{–1}$. Using two direct electrocaloric measurement methods, we demonstrated that the electrocaloric temperature change in the prepared PMN–35PT thick-film structures reaches a maximum of 0.87 K at 63.5 °C and 300 kV cm$^{–1}$, which exceeds the value of 0.72 K at ∼65 °C and 60 kV cm$^{–1}$ reported for bulk ceramics of the same composition. The PMN–35PT thick films prepared here are thick-film structures with excellent flexibility, promising for future multifunctional microsystems that manage multiple energy operations, enabling comprehensive energy harvesting, storage and conversion to thermal energy.20232023-11-22 15:53:10Članek v reviji152369sl