Proton tautomerism for strong polarization switching.
Proton tautomerism for strong polarization switching.
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DOI：
10.1038/ncomms14426
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发表时间：
2017-02-16
影响因子：
16.6
通讯作者：
Ishibashi S
中科院分区：
文献类型：
--
作者：
Horiuchi S;Kobayashi K;Kumai R;Ishibashi S
基于质子互变异构的铁电体在低场和高于室温的操作中具有广阔的前景。这里检查了七个有机铁电晶体，以寻找质子互变异构上强自发极化的有效转换。溶液生长的晶体表现出强烈的铁电畴壁钉扎，但通过在热退火和/或高电压重复双极脉冲下使畴壁脱钉，可以唤醒优异的开关性能。与聚偏二氟乙烯等铁电聚合物相比，优化后的极化强度相当或更强，而矫顽场则弱两个数量级。特别是克罗康酸的极化，打破了它自己的有机体系记录，从 21 增加到 30μCcm−2，现在超过了一些商用铁电材料，如 SrBi2Ta2O9 和 BaTiO3。通过优化，自发极化与第一性原理计算结果的偏差降低到15%以内。通过采用点电荷模型和氢键几何结构讨论了质子转移和π键转换的协同作用。基于质子互变异构的铁电体在低场和高于室温的操作中具有广阔的前景。在这里，作者建立了一个优化自发极化的程序，发现克罗康酸的极化打破了有机系统的记录。
Ferroelectrics based on proton tautomerism are promising in low-field and above-room-temperature operations. Here seven organic ferroelectric crystals are examined to search for efficient switching of strong spontaneous polarization on proton tautomerism. Solution-grown crystals exhibit strong pinning of ferroelectric domain walls, but excellent switching performance is awakened by depinning domain walls under thermal annealing and/or repetitive bipolar pulses with a high voltage. Compared with ferroelectric polymers such as polyvinylidefluoride, the optimized polarizations are comparable or stronger in magnitude whereas the coercive fields are two orders of magnitude weaker. The polarization of croconic acid, in particular, breaks its own record for organic systems in increasing from 21 to 30 μC cm−2 and now exceeds those of some commercial ferroelectric materials such as SrBi2Ta2O9 and BaTiO3. Optimization reduces the discrepancy of the spontaneous polarization with the results of the first-principles calculations to less than 15%. The cooperative roles of proton transfer and π-bond switching are discussed by employing the point-charge model and hydrogen-bond geometry. Ferroelectrics based on proton tautomerism are promising in low-field and above-roomtemperature operations. Here the authors establish a procedure to optimize spontaneous polarizations, finding that the polarization in croconic acid breaks its own record for organic systems.