Infinitesimal amount of perovskite quantum dots enhances electrocaloric cooling performances in diluted nanocomposites

The advancement of high-performance electrocaloric (EC) cooling devices necessitates materials that exhibit robust EC effects under practical electric fields and that are suitable for industrial-scale production. Relaxor ferroelectric polymer nanocomposites represent a promising avenue. However, achieving high EC responses in current nanocomposites typically requires filler contents exceeding 5 vol %, resulting in material nonuniformity that limits practical applications. Here, we introduce a novel approach using nanocomposites with infinitesimally low loading of fillers that exploits interface effects to amplify dipolar responses, thereby significantly reducing the necessary filler content. We demonstrated that incorporating only 0.02 vol % CsPbBr₃ perovskite quantum dots into P(VDF-TrFE-CFE) doubled the EC effect, with a filler content an order of magnitude lower than those previously reported. Our findings provide a clear structural understanding of how dilute nanocomposites enhance the dipolar response in polymeric materials and extend this promising concept for improved dipolar response-related properties to ferroelectric materials.