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High Ambipolar Mobility in a Neutral Radical Gold Dithiolene Complex
Author(s) -
Mizuno Asato,
Benjamin Helen,
Shimizu Yasuhiro,
Shuku Yoshiaki,
Matsushita Michio M.,
Robertson Neil,
Awaga Kunio
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201904181
Subject(s) - ambipolar diffusion , materials science , charge carrier , crystallography , single crystal , stacking , chemical physics , condensed matter physics , optoelectronics , electron , nuclear magnetic resonance , chemistry , physics , quantum mechanics
A new anionic gold dithiolene complex NBu 4 ·[1] is synthesized from the (1‐((1,1‐biphenyl)‐4‐yl‐)‐ethylene‐1,2‐dithiolene ligand 1, and the cis and trans isomers are separated by recrystallization. The trans isomer is oxidized via electrocrystallisation to the neutral gold dithiolene complex 2. Complex 2 crystalizes in 1D chains, held together by short (3.30–3.37 Å) S–S contacts, which are packed in a herringbone arrangement in the ab ‐plane. The complex exhibits semiconductor behavior (σ RT = 1.5 × 10 −4 S cm −1 ) at room temperature with a small activation energy ( E a = 0.11 eV), with greater conductivity along the stacking direction. The charge transport behavior of complex 2 is further investigated in single‐crystal field‐effect transistor (FET) measurements, the first such measurements reported for gold dithiolene complexes. Complex 2 shows incredibly balanced ambipolar behavior in the single‐crystal field‐effect transistor (SC‐FET), with high charge‐carrier mobilities of 0.078 cm 2 V −1 s −1 , the highest ambipolar mobilities reported for metal dithiolene complexes. This well‐balanced behavior, along with the activated conductivity and band structure calculations, suggests that 2 behaves as a Mott insulator. The magnetic properties are also studied by superconducting quantum interference device (SQUID) magnetometry and solid state 1 H NMR, with evidence of a nonmagnetic ground state at low temperature.