Double-Bond-induced Morphotropic Phase Boundary leads to Enhanced Electrocaloric Effect in VDF-Based Polymer Flexible Devices

Electrocaloric (EC) polymers answer the needs for green, efficient, and flexible coolers as well as thermal management in wearable electronics. A morphotropic phase boundary is induced for the first time in P(VDF-ter-TrFE-ter-CFE) polymers near room temperature, by soft one-pot addition of small fractions of double bonds. It results in flexible devices with remarkable cooling performance, Delta T-EC = 5.8 K for E < 100 MVm(-1) and up to 9.3 K at higher fields, which are maintained when bent to various angles required for wearable electronics. This work paves the way for the development of scalable, high-performance, and flexible organic cooling devices.