Large electrocaloric strength in ferroelectric nematic liquid crystals with a tuneable operational temperature range
Authors
Diana I. Nikolova
Rachel Tuffin
Mengfan Guo
Neil D. Mathur
Xavier Moya
Peter Tipping
Richard J. Mandle
Helen F. Gleeson
Abstract
The electrocaloric (EC) effect offers a promising energy-efficient and clean cooling technology. We present the first direct measurements of EC temperature change in a new family of EC fluids, ferroelectric nematic liquid crystals (FNLCs), demonstrating in two such materials temperature jumps of $|ΔT_j|$ ~ 0.2 K for field changes as low as $ΔE$ ~ 0.1 $V μm^{-1}$. Indirect measurements of adiabatic temperature change $|ΔT|$ confirm that these direct measurements are an underestimate and that $ΔE$ = 2 $V μm^{-1}$ can induce up to $|ΔT|$ ~ 1.6 K, yielding EC strengths $|ΔT/ΔE|$ up to 100% higher than incumbent materials. For temperature spans of 5-10 K, we predict a coefficient of performance of ~21-40. We find $|ΔT|$ ~ 1 K for >100 FNLCs that collectively span all temperatures between $0{^\circ}$C and $100{^\circ}$C. This, together with the new device concepts conceivable with fluid EC materials, offers huge potential for cooling applications.
