Spin Transition in Arrays of Gold Nanoparticles and Spin Crossover Molecules
Journal article, 2015
We investigate if the functionality of spin crossover molecules is preserved when they are assembled into an interfacial device structure. Specifically, we prepare and investigate gold nanoparticle arrays, into which room-temperature spin crossover molecules are introduced, more precisely, [Fe(AcS-BPP)(2)](ClO4)(2), where AcS-BPP = (S)-(4-{[2,6-(dipyrazol-1-yl)pyrid-4-yl]ethynyl}phenyl)ethanethioate (in short, Fe(S-BPP)(2)). We combine three complementary experiments to characterize the molecule-nanoparticle structure in detail. Temperature-dependent Raman measurements provide direct evidence for a (partial) spin transition in the Fe(S-BPP)(2)-based arrays. This transition is qualitatively confirmed by magnetization measurements. Finally, charge transport measurements on the Fe(S-BPP)(2)-gold nanoparticle devices reveal a minimum in device resistance versus temperature, R(T), curves around 260-290 K. This is in contrast to similar networks containing passive molecules only that show monotonically decreasing R(T) characteristics. Backed by density functional theory calculations on single molecular conductance values for both spin states, we propose to relate the resistance minimum in R(T) to a spin transition under the hypothesis that (1) the molecular resistance of the high spin state is larger than that of the low spin state and (2) transport in the array is governed by a percolation model.
spin crossover molecules
self-assembly
molecular charge transport devices
gold nanoparticles
Author
E. J. Devid
Leiden University
P. N. Martinho
Karlsruhe Institute of Technology, Campus North
Universidade de Lisboa
Venkata Kamalakar Mutta
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
I. Salitros
Slovak University of Technology in Bratislava
Karlsruhe Institute of Technology, Campus North
U. Prendergast
Dublin City University
J. F. Dayen
Universite de Strasbourg
V. Meded
Karlsruhe Institute of Technology, Campus North
T. Lemma
Dublin City University
R. Gonzalez-Prieto
Karlsruhe Institute of Technology, Campus North
Universidad Autonoma de Madrid
F. Evers
Karlsruhe Institute of Technology, Campus North
Karlsruhe Institute of Technology, Campus South
T. E. Keyes
Dublin City University
M. Ruben
Universite de Strasbourg
Karlsruhe Institute of Technology, Campus North
B. Doudin
Universite de Strasbourg
S. J. van der Molen
Leiden University
ACS Nano
1936-0851 (ISSN) 1936-086X (eISSN)
Vol. 9 4 4496-4507Subject Categories (SSIF 2011)
Nano Technology
DOI
10.1021/acsnano.5b01103