Electrical Conductivity of Organic Semiconductors

Conducting π Columns of Highly Symmetric Coronene, The Smallest Fragment of Graphene

“…At room temperature, both salts show a rather high conductivity along the stacking direction, 0.05 S cm −1 for 1 and 3.0 S cm −1 for 2 . It is noteworthy that the σ values are more than 10 orders of magnitude higher than that of the pristine coronene solid (<10 −12 S cm −1 ) . Furthermore, the value of σ for 2 at room temperature increases with increasing pressure and reaches a maximum of as high as 9.4 S cm −1 at 4.0 GPa (Figure b); the value of E a also exhibits a broad minimum at around 2–3 GPa.…”

“…As seen in Figure a, both salts 1 and 2 show semi‐conducting behaviour; that is, the electrical conductivities ( σ ) follow the Arrhenius law ( σ = σ 0 exp (− E a / k B T ), in which k B is the Boltzmann constant and E a is the activation energy) with activation energies ( E a ) of 44 meV for 1 and 29 meV for 2 at >123 K. The E a values are apparently lower than those of pristine coronene (0.8–1.3 eV), (coronene)(TCNQ) (0.49 eV) and 3 (79 meV) . At room temperature, both salts show a rather high conductivity along the stacking direction, 0.05 S cm −1 for 1 and 3.0 S cm −1 for 2 .…”

Photoelectric Emission from Donor-Acceptor Solids and Donor Molecules

“…The photon energy necessary to dissipate the space-charge was 2.6 eV, close t o the reported photoconduction threshold. 22 Although Ie was independent of the state of the sample, the shape of the yield curve was not. In general, as the photon energy v increased above the threshold vt the logarithm of the yield tended to level off a t a value of about -3.…”

Bulk crystals of tetracene grown by the vapor-Bridgman technique

“…13 The lifting mechanism was started and the reflector lowered at a speed of 0.42 mm/ h. As the capillary entered the cooler part of the furnace, nucleation took place. Prior to growth, the pristine material was purified by two successive sublimation steps in vacuum.…”