Unraveling the Influence of Lanthanide Ions on Intra- and Inter-Molecular Electronic Processes in Fe(10)Ln(10) Nano-Toruses

作者：Baniodeh Amer^*; Liang Yu; Anson Christopher E; Magnani Nicola; Powell Annie K; Unterreiner Andreas Neil; Seyfferle Simon; Slota Michael; Dressel Martin; Bogani Lapo; Goss Karin

来源：Advanced Functional Materials, 2014, 24(40): 6280-6290.

DOI：10.1002/adfm.201400336

We investigated the electronic properties of the molecular magnetic nanotoruses [Fe(III)10Ln(III)10(Me-tea)(10)(Me-teaH)(10)(NO3)(10)], examining the dependence on the lanthanide (Ln) of both the intra and intermolecular electronic channels. Using femtosecond absorption spectroscopy we show that the intramolecular electronic channels follow a three-step process, which involves vibrational cooling and crossing to shallow states, followed by recombination. A comparison with the energy gaps showed a relationship between trap efficiency and gaps, indicating that lanthanide ions create trap states to form excitons after photo-excitation. Using high-resistance transport measurements and scaling techniques, we investigated the intermolecular transport, demonstrating the dominant role of surface-limited transport channels and the presence of different types of charge traps. The intermolecular transport properties can be rationalized in terms of a hopping model, and a connection is provided to the far-IR spectroscopic properties. Comparison between intra and intermolecular processes highlights the role of the excited electronic states and the recombination processes, showing the influence of Kramers parity on the overall mobility.

• 出版日期2014-10-29