Photoelectrocaloric effect in ferroelectric oxide

The enhanced electrocaloric (EC) effect in solid-state-based lead-free ferroelectric Ba_0.875(Bi_0.5Li_0.5)_0.125TiO₃ system is investigated under light as an external stimulus. The sample exhibits an analogous value of maximum change in entropy at Curie temperature, extracted from the two different measurements process. Notably, the sample depicts maximum value of adiabatic change in temperature (ΔT) as 1.27 K and isothermal entropy change (ΔS) as 2.05 J/K kg along with the EC coefficient value of 0.426 K mm/kV, under dark conditions. In addition, the sample exhibits > 0.5 K adiabatic temperature change over a broad temperature range (~ 35 K). Remarkably, the EC parameters display ~ 27% enhancement upon 405 nm light illumination. The demonstrated photoelectrocaloric effect is found to be in accordance with theoretical formalism. The present work elucidates the light as an additional degree of freedom to widen the potential of solid-state-based technologies for advanced environment-friendly cooling devices.