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arXiv · 0707.0461

High charge-carrier mobility and low trap density in a rubrene derivative

S. Haas·A. F. Stassen·G. Schuck·K. P. Pernstich·D. J. Gundlach·B. Batlogg·U. Berens·H. -J. Kirner
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Abstract

We have synthesized, crystallized and studied the structural and electric transport properties of organic molecular crystals based on a rubrene derivative with {\em t}-butyl sidegroups at the 5,11 positions. Two crystalline modifications are observed: one (A) distinct from that of rubrene with larger spacings between the naphtacene backbones, the other (B) with a in-plane structure presumably very similar compared to rubrene. The electric transport properties reflect the different structures: in the latter phase (B) the in-plane hole mobility of 12 cm$^2$/Vs measured on single crystal FETs is just as high as in rubrene crystals, while in the A phase no field-effect could be measured. The high crystal quality, studied in detail for B, reflects itself in the density of gap states: The deep-level trap density as low as $10^{15}$ cm$^{-3}$ eV$^{-1}$ has been measured, and an exponential band tail with a characteristic energy of 22 meV is observed. The bulk mobility perpendicular to the molecular planes is estimated to be of order of $10^{-3}$ -- $10^{-1}$ cm$^2$/Vs.

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S. Haas, A. F. Stassen, G. Schuck, K. P. Pernstich, D. J. Gundlach, B. Batlogg, U. Berens, H. -J. Kirner. 2007-07-03. High charge-carrier mobility and low trap density in a rubrene derivative. https://doi.org/10.1103/physrevb.76.115203

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