Huge electrocaloric effect in Langmuir–Blodgett ferroelectric polymer thin films

Liu, Pengzhan; Wang, J L; Meng, Xiangjian; Yang, Jing; Dkhil, Brahim; Chu, Jun

doi:10.1088/1367-2630/12/2/023035

Cited by 93 publications

(56 citation statements)

References 24 publications

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“…The results indicate that the Maxwell relation is not suitable for ECE characterization for the relaxor ferroelectric polymers even at temperatures above the broad dielectric constant maximum. This is likely caused by the non-ergodic behaviour of relaxor ferroelectric polymers even at temperatures above the dielectric constant maximum while the Maxwell relations are valid only for thermodynamically equilibrium systems (ergodic systems) We also note that a recent report of ECE deduced from the Maxwell relation on a P(VDFTrFE-CFE) relaxor ferroelectric terpolymer by Liu et al (Liu et al 2010) shows very irregular field dependence of ECE measured at temperatures below 320 K where ECE in fact decreases with field, which is apparently not correct. These results all indicate that the Maxwell relation cannot be used to deduce ECE for the relaxor ferroelectric polymers, or even the relaxor ferroelectric materials in general, even at temperatures far above the freezing transition and the broad dielectric constant peak temperature.…”

Section: Ece In the Relaxor Ferroelectric P(vdf-trfe-cfe) Terpolymersmentioning

confidence: 88%

The electrocaloric effect (ECE) in ferroelectric polymer films

Lu¹,

Zhang²,

Kutnjak³

2011

Thin Film Growth

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Section: Ece In the Relaxor Ferroelectric P(vdf-trfe-cfe) Terpolymersmentioning

confidence: 88%

The electrocaloric effect (ECE) in ferroelectric polymer films

Lu¹,

Zhang²,

Kutnjak³

2011

Thin Film Growth

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“…On the other hand, we have mainly concentrated on reviewing the inorganic electrocalorics, while there is no denying that polymeric materials such as copolymers of PVDF and trifluoroethylene are also very promising for developing electrocaloric prototype devices due to their large electrocaloric response and flexible nature. 17,55,123 Review on organic electrocalorics can be found in Refs. 1, 3, 4, and 6.…”

Section: Perspectivesmentioning

confidence: 99%

Direct and indirect measurements on electrocaloric effect: Recent developments and perspectives

Liu

Scott

Dkhil

2016

Applied Physics Reviews

232

150

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It has been ten years since the discovery of the giant electrocaloric effect in ferroelectric materials showed that it is possible to employ this effect for substantial cooling applications. This last decade has been marked by increasing research interest, especially in characterizing and measuring the electrocaloric effect using both the so-called indirect and direct approaches. In this context, a comprehensive summary and careful reexamination of these approaches are very timely and of great importance to justify the assumptions used in different measurement techniques. This review is therefore dedicated to cover recent important and rapid advances from both the indirect and direct measurements and provides critical insights relevant for quantifying the electrocaloric effect. It involves electrocaloric materials from normal ferroelectrics, antiferroelectrics, and relaxors, and it fundamentally focuses on how the electrocaloric entropy changes in response to electric field in these typical electrocalorics. The article addresses recent developments, especially during the past three years, such as technical selection of proper polarization-electric field loops, negative electrocaloric effect in antiferroelectrics and relaxors, the controversial debate on the indirect method in relaxors, the important role of field dependence of specific heat, kinetic factors, and so on. Moreover, this review also is concerned with extracting reliable data by direct measurements. Four typical techniques and devices used recently, such as thermocouples, differential scanning calorimeters, specifically designed calorimeters, and scanning thermal microscopy, are briefly reviewed, while infrared cameras are emphasized. We hope that our review will not only provide a useful background to understand fundamentally the electrocaloric effect and what one really measures but also may act as a practical guide to exploit and develop electrocalorics towards the design of suitable devices. Published by AIP Publishing. [http://dx

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“…Indeed, ∆T E in Pt/BaTiO 3 /SrRuO 3 junctions is at least twice 39,40 Given that ∆T E /∆E in ferroelectric thin films is usually smaller than in bulk. Here, ∆T E /∆E decreases even further as the film thickness decreases to only a few nanometers (see Table I in Ref.…”

Section: 3mentioning

confidence: 99%

Some strategies for improving caloric responses with ferroelectrics

2016

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Many important breakthroughs and significant engineering developments have been achieved during the past two decades in the field of caloric materials. In this review, we address ferroelectrics emerging as ideal materials which permit both giant elastocaloric and/or electrocaloric responses near room temperature. We summarize recent strategies for improving caloric responses using geometrical optimization, maximizing the number of coexisting phases, combining positive and negative caloric responses, introducing extra degree of freedom like mechanical stress/pressure, and multicaloric effect driven by either single stimulus or multiple stimuli. This review highlights the promising perspective of ferroelectrics for developing next-generation solid-state refrigeration.

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Huge electrocaloric effect in Langmuir–Blodgett ferroelectric polymer thin films

Cited by 93 publications

References 24 publications

The electrocaloric effect (ECE) in ferroelectric polymer films

The electrocaloric effect (ECE) in ferroelectric polymer films

Direct and indirect measurements on electrocaloric effect: Recent developments and perspectives

Some strategies for improving caloric responses with ferroelectrics

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