Comparing small molecules and polymer for future organic spin-valves
Comparing small molecules and polymer for future organic spin-valves
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DOI：
10.1016/j.jallcom.2005.12.104
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发表时间：
2006-10
影响因子：
6.2
通讯作者：
S. Majumdar;H. Majumdar;R. Laiho;R. Österbacka
中科院分区：
文献类型：
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作者：
S. Majumdar;H. Majumdar;R. Laiho;R. Österbacka
我们报道了有机小分子和聚合物自旋阀中的自旋极化注入和输运。采用真空蒸发的π共轭小分子8-羟基喹啉铝（Alq 3）制备的La0.67Sr0.33MnO3（LSMO）/有机间隔层/Co结构的器件表现出逆磁电阻效应和低温工作特性，而采用π共轭聚合物聚3-己基噻吩制备的器件表现出正常的磁电阻效应和高温工作特性。由于LSMO和Co的功函数与聚合物的最高占据分子轨道（HOMO）能量的接近值，与Alq 3的有机自旋阀相比，自旋极化载流子注入在聚合物自旋阀中更有效，其中载流子注入由于更大的势垒高度而受阻。在聚合物自旋阀中也观察到有效的自旋输运，并且可以归因于与小分子相比聚合物链中更长的共轭。
We report spin polarized injection and transport in organic spin-valves made from both organic small molecules and polymers. The devices with the structure La0.67Sr0.33MnO3(LSMO)/organic spacer/Co showed inverse magnetoresistance and low temperature operation with the vacuum evaporated π-conjugated small molecule 8-hydroxyquinoline aluminium (Alq3) while normal MR and high temperature operation was observed in devices with the π-conjugated polymer poly(3-hexylthiophene). Due to the proximate values of the work functions of LSMO and Co with the highest occupied molecular orbital (HOMO) energy of the polymers, spin polarized carrier injection is much more efficient in the polymeric spin-valves compared to the organic spin-valves with Alq3where carrier injection is hindered due to greater barrier height. Efficient spin transport is also observed in polymeric spin-valves and can be attributed to longer conjugation in the polymeric chains compared to the small molecules.