Inducing a high twisted conformation in the polyimide structure by bulky donor moieties for the development of non-volatile memory
Inducing a high twisted conformation in the polyimide structure by bulky donor moieties for the development of non-volatile memory
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DOI：
10.1016/j.eurpolymj.2013.07.016
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发表时间：
2013-10
影响因子：
6
通讯作者：
Tadanori Kurosawa;An-dih Yu;Tomoya Higashihara;Wen‐Chang Chen;M. Ueda
中科院分区：
文献类型：
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作者：
Tadanori Kurosawa;An-dih Yu;Tomoya Higashihara;Wen‐Chang Chen;M. Ueda
以N-（2，4-二氨基苯基）-N，N-二苯胺（DAT）或N-（4-（2′，4 ′-二氨基苯氧基）苯基）-N，N-二苯胺（DAPT）和4，4 ′-（六氟异亚丙基）二邻苯二甲酸酐（6 FDA）为原料合成了两种聚酰亚胺PI（DAT-6 FDA）和PI（DAPT-6 FDA），研究了结构对记忆性能的影响。基于PI（DAT-6 FDA）的存储器件表现出不稳定的易失性行为，而基于PI（DAPT-6 FDA）的具有更大供体（D）单元的器件表现出稳定的非易失性FLASH型存储器特性，具有超过104 s的长保留时间。基于密度泛函理论（DFT）的理论模拟表明，基态和电荷转移态（CT）之间更大的电荷分离导致了高度稳定的记忆行为。此外，阐明了PI（DAPT-6 FDA）在基态下与PI（DAT-6 FDA）相比具有高度扭曲的构象，并且在CT状态下诱导D和受体（A）单元之间的更扭曲的二面角，这导致非易失性存储特性。
Two polyimides, PI(DAT-6FDA) and PI(DAPT-6FDA), fromN-(2,4-diaminophenyl)-N,N-diphenylamine (DAT) orN-(4-(2′,4′-diaminophenoxy)phenyl-N,N-diphenylamine (DAPT) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) were prepared to clarify the structural effect on the resulting memory properties. The memory device based on PI(DAT-6FDA) showed an unstable volatile behavior, while the device based on PI(DAPT-6FDA) with a more bulky donor (D) unit exhibited a stable non-volatile FLASH type memory characteristic with a long retention time over 104s. The theoretical simulation based on the density functional theory (DFT) suggested that the greater distinct charge separation between the ground and charge transfer (CT) states led to a highly stable memory behavior. Also, it was clarified that PI(DAPT-6FDA) had a highly twisted conformation compared to PI(DAT-6FDA) in the ground state, and a more twisted dihedral angle between the D and acceptor (A) units was induced in the CT state, which led to the non-volatile memory characteristic.