Viologen-based conjugated ionic polymer for nonvolatile rewritable memory device
Viologen-based conjugated ionic polymer for nonvolatile rewritable memory device
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DOI：
10.1016/j.eurpolymj.2017.07.010
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发表时间：
2017-09
影响因子：
6
通讯作者：
Luxing Wang;Sai Sun;Bin Zhang;Lingyun Yang;Yefeng Yao;Xiaodong Zhuang;Yu Chen
中科院分区：
文献类型：
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作者：
Luxing Wang;Sai Sun;Bin Zhang;Lingyun Yang;Yefeng Yao;Xiaodong Zhuang;Yu Chen
以四（三苯基膦）钯（0）为催化剂，通过Suzuki偶联反应合成了一种新型的可溶性紫精基共轭离子共聚物PTPA-V。从CV数据得到的HOMO、LUMO、EA、IP和Eg值分别为− 5.44、− 3.10、3.07、5.70和2.34 eV。在PTPA-V薄膜的UV/维斯吸收光谱中观察到的最大吸收峰向红移动了约10 nm，表明薄膜中发生了较强的聚集效应。PTPA-V单重激发态在不同脱气有机溶剂中的荧光衰减曲线显示单指数衰减，寿命为8.9 ns（甲苯）、6.4 ns（THF）和5.2 ns（DMF）。所制备的Al/PTPA-V/ITO结构的电子器件具有两种可达到的导电状态，即高导电（ON）状态和低导电（OFF）状态。观察到典型的非易失性DRAM存储器行为，开启和关闭电压为-1.92 V和2.67 V，以及大于10 5的大ON/OFF电流比。与没有任何电子顺磁共振（EPR）信号的聚（三苯胺）不同，PTPA-V显示g因子为2.004的EPR信号，表明由于三苯胺（TPA）部分和紫精（V）部分之间的电荷转移，在该聚合物中存在未配对电子或自由基，这导致TPA+和V-的形成。
A novel soluble viologen-based conjugated ionic copolymer, PTPA-V, was synthesized by using Suzuki coupling reaction in the presence of the tetrakis (triphenylphosphine) palladium (0) as the catalyst. Its HOMO, LUMO, EA, IP and Eg values derived from the CV data are− 5.44,− 3.10, 3.07, 5.70 and 2.34 eV, respectively. The maximum absorption peak observed in the UV/Vis absorption spectrum of the PTPA-V thin film was shifted to the red by about 10 nm, suggesting stronger aggregation effect occurred in the thin film. The fluorescence decay profiles of the singlet excited state of PTPA-V in different deaerated organic solvents revealed a mono-exponential decay with a lifetime of 8.9 ns (toluene), 6.4 ns (THF) and 5.2 ns (DMF). The as-prepared electronic device with a configuration of Al/PTPA-V/ITO exhibited two accessible conductivity states, ie, the high-conductivity (ON) state and the low-conductivity (OFF) state. A typical nonvolatile rewritable memory behavior was observed, with turn-on and turn-off voltages of− 1.92 and 2.67 V, and a large ON/OFF current ratio of more than 10 5. Unlike poly (triphenylamine) without any electron paramagnetic resonance (EPR) signal, PTPA-V shows an EPR signal with a g factor of 2.004, suggesting existence of unpaired electrons or free radicals in this polymer due to the charge transfer between the triphenylamine (TPA) moieties and the viologen (V) moieties, which resulted in the formation of TPA+ and V-.