Magnetocurrent of Charge-Polarizable C60-Diphenylaminofluorene Monoadduct-Derived Magnetic Nanocomposites

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• 作者：Liang Yan ; Min Wang ; N. P. Raju ; Arthur Epstein ; Loon-Seng Tan ; Augustine Urbas ; Long Y. Chiang ; Bin Hu
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：February 22, 2012
• 年：2012
• 卷：134
• 期：7
• 页码：3549-3554
• 全文大小：425K
• 年卷期：v.134,no.7(February 22, 2012)
• ISSN：1520-5126

文摘

We demonstrated the strategy of a nanocomposite design by the incorporation of both a delocalized 蟺-electrons system in a closely bound acceptor鈥揹onor analogue chromophore, based on charge-polarizable C₆₀(>DPAF-C₉) nanostructure 1, and spin-polarized d-electrons in the form of 纬-FeO_x nanoparticles. Facile intramolecular electron transfer from the DPAF-C₉ donor moiety to the C₆₀ acceptor cage of 1 upon activation to the excited state with a long lifetime of the charge-separated state forms a possible mechanism to integrate semiconducting and magnetic properties in a single system. We observed an appreciable magnetocurrent (MC) of C₆₀(>DPAF-C₉)-encapsulated magnetic 纬-FeO_x nanoparticles in PMMA matrix upon applying a magnetic field from 0 to 300 mT at either 77 K (12% MC) or 300 K (4.5% MC). Interestingly, the detailed analysis of magnetocurrent curve profiles taken at 77 K allowed us to conclude that the measured magnetocurrent may be attributed to the contributions from magnetic field-dependent excited-state populations in semiconducting structure (density-based MC), magnetism from magnetic structure (mobility-based MC), and product of density and mobility-based MC components (蟺鈥揹 electronic coupling). At the higher temperature region up to 300 K, the semiconducting mechanism dominated the determining factor of measured magnetocurrent. This experimental observation indicated the feasibility of combining delocalized 蟺 electrons and spin-polarized d electrons through charge transfer to induce internally coupled dual mobility- and density-based MC through the modulation of spin polarization and excited states in semiconducting/magnetic hybrid materials.