Electrical conductivity by the bis(1,3-dithiole)-bis(1,3-dithiolium) system
Electrical conductivity by the bis(1,3-dithiole)-bis(1,3-dithiolium) system
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DOI：
10.1021/ja00757a079
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发表时间：
1972
影响因子：
15
通讯作者：
F. Wudl;D. Wobschall;E. J. Hufnagel
中科院分区：
文献类型：
--
作者：
F. Wudl;D. Wobschall;E. J. Hufnagel
measurement was performed on a single crystal (in an inert atmosphere) by the four-electrode method4 using platinum electrodes and silver-base adhesive. No noticeable electrolysis was detected afterprolonged passage of current (at 5-10V) indicating that the con-duction mechanism was electronic. 4 As a single crys-tal, 2 is a better conductor than anthracene (p= 1022 cm) 10 or ferrocene (p= 14 cm). 5 Consequently, the intermolecular barriers to the mobility of charge carriers appearedto be lower in 2 (however, vide infra) than in other comparable organic solids. Since it is necessary to excite 2 with light in order to achieve removal of an electron by molecular oxygen, we presumed that photopromotion of an electron from the valence band to the conduction band in 2 may be quite efficient with concomitant enhancement of electrical conductance. Figure 1 depicts the photocurrent pattern of 2. Clearly, it appeared as though 2 was a photoconducting molecule. In order to gain better insight into the mechanism of photoconduction, we studied the wavelength de-pendence of the photocurrent (cf. Figure 2). How-ever, the maximum in Figure 2 does not correspond to any of the absorption maximain the electronic ab-sorption spectrum of 2. On the other hand, 1 exhibits a strong absorption at 575 nm (e1. 6 X 104). Therefore, we were forced to concludethat 2 was not responsible for the photocurrent but that it was contaminated with a trace of 1. Furthermore, the dark conductance measurements performed on“pure” 2 (vide supra6) should now be considered with suspicion. Finally, we directed our attention to the electrical properties of 1 and found it to be an excellent organic solid-state semiconductor. It exhibits a room tempera-ture resistivity of 3.7± 1 cm (E= 10 V). The
