Manipulation of electrocaloric response through interface engineering

Electrocaloric solid-state cooling is promising for chip-level thermal management, yet a key obstacle is that many ferroelectric thin films deliver their strongest electrocaloric response at temperatures outside the typical operating range of on-chip electronics. Here, we use heterointerface engineering to enhance electrocaloric performance while shifting the operating window toward room temperature. In [BSZT/BNBT]2 multilayers, an isothermal entropy change of 26.3 J K−1 kg−1 and an adiabatic temperature change of 16.9 K are achieved at about 30 °C under 625 kV cm−1. Cross-sectional potential measurements reveal an interfacial built-in field of 3.8 kV cm−1, which reshapes the local thermodynamic landscape and stabilizes weakly polarized, orientationally disordered competing polar states near the interface. Their reversible reorganization under bias enhances polarization change and electrocaloric response. The multilayers show a high electrocaloric strength of 0.0271 K cm kV−1 near room temperature, highlighting interface engineering as a scalable strategy for chip-integrated electrocaloric refrigeration.