Browsing by Author "Zou, Bingsuo"

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    Phase-transition induced giant negative electrocaloric effect in a lead-free relaxor ferroelectric thin film
    (Royal Society of Chemistry, 2019-05-02) Peng, Biaolin; Zhang, Qi; Gang, Bai; Leighton, Glenn J. T.; Shaw, Christopher; Milne, Steven J.; Zou, Bingsuo; Sun, Wenhong; Huang, Haitao; Wang, Zhonglin
    Ferroelectric/antiferroelectric thin/thick films with large positive or negative electrocaloric (EC) effects could be very useful in designing commercial refrigeration devices. Here, a giant negative EC effect (maximum ΔT ∼ −42.5 K with ΔS ∼ −29.3 J K−1 kg−1) comparable to the best positive EC effects reported so far is demonstrated for 0.5(Ba0.8Ca0.2)TiO3–0.5Bi(Mg0.5Ti0.5)O3 (BCT–BMT) lead-free relaxor ferroelectric thin films prepared on Pt(111)/TiOx/SiO2/Si substrates using a sol–gel method. An electric-field induced structural phase transition (nanoscale tetragonal and orthorhombic to rhombohedral) along the out-of-plane [111] direction plays a very key role in developing the giant negative EC effect. This breakthrough will pave the way for practical applications of next-generation refrigeration devices with high cooling efficiency in one cycle by ingeniously utilizing and combining both the giant negative and positive EC effects. Moreover, a large energy density of 51.7 J cm−3 with a high power density of 1.15 × 1010 W kg−1 at room temperature is also achieved in the thin film, indicating that it is also an attractive multifunctional material for energy storage.
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    Tailoring the electrocaloric effect of Pb0.78Ba0.2La0.02ZrO3 relaxor thin film by GaN substrates
    (Royal Society of Chemistry, 2019-11-06) Peng, Biaolin; Jiang, Jintao; Tang, Silin; Zhang, Miaomiao; Liu, Laijun; Zou, Bingsuo; Leighton, Glenn J. T.; Shaw, Christopher; Luo, Nengneng; Zhang, Qi; Sun, Wenhong
    The electrocaloric (EC) effect in ferroelectric/antiferroelectric thin films has been widely investigated due to its potential applications in solid state cooling devices. It is demonstrated that the EC effect of the Pb0.78Ba0.2La0.02ZrO3 (PBLZ) relaxor thin films prepared by using a sol–gel method strongly depends on the substrates. The maximum ΔT of PBLZ thin films deposited on Pt(111)/TiOx/SiO2/Si(100) (Pt), LaNiO3/Pt(111)/TiOx/SiO2/Si(100) (LaNiO3/Pt), LaNiO3/n-type GaN (LaNiO3/n-GaN) and LaNiO3/p-type GaN (LaNiO3/p-GaN) substrates is ∼13.08 K, 16.46 K, 18.70 K, and 14.64 K, respectively. Moreover, negative EC effects in a broad temperature range (∼340 K to 440 K) could be obtained in the thin films deposited on LaNiO3/n-GaN and LaNiO3/p-GaN substrates, which is ascribed to higher proportions of orthorhombic antiferroelectric phase to rhombohedral ferroelectric phase induced by the GaN substrates. These results indicate that tailoring the EC effects by changing the substrates could provide a new strategy in designing an EC cooling device with high cooling efficiency.