Comparing small molecules and polymer for future organic spin-valves

Sayani Majumdar (Corresponding Author), Himadri S. Majumdar, Reino Laiho, R. Osterbacka

Research output: Contribution to journalArticleScientificpeer-review

66 Citations (Scopus)

Abstract

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 Alq3 where 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.
Original languageEnglish
Pages (from-to)169-171
JournalJournal of Alloys and Compounds
Volume432
Issue number1-2
DOIs
Publication statusPublished - 2006
MoE publication typeA1 Journal article-refereed

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