Transient photoconduction in discotic liquid crystals
Transient photoconduction in discotic liquid crystals
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DOI：
10.1039/a808615j
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发表时间：
1999
影响因子：
3.3
通讯作者：
A. Ochse;A. Kettner;J. Kopitzke;J. Wendorff;H. Bässler
中科院分区：
文献类型：
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作者：
A. Ochse;A. Kettner;J. Kopitzke;J. Wendorff;H. Bässler
研究了酯取代的六烷氧基三苯化合物的空穴传输性质，并与未取代的材料进行了比较。最近研究的六烷氧基三苯撑型双折射液晶的高空穴迁移率被限制在它们的中间相的非常小的温度范围内。它通过一个酯基的取代而基本上延伸，因为这阻碍了结晶并导致玻璃形成。结果发现，酯基的取代完全改变了迁移率的温度和场依赖性。在酯取代的化合物中，迁移率μ与温度无关，但遵循ln μ π ι 1/T2定律。我们将此归因于酯基的偶极矩，其引起局部电场中的随机波动，并导致以无序为主的电荷载流子跳跃作为占主导地位的传输机制。
The hole transport properties of ester substituted hexaalkyloxytriphenylenes are investigated and compared with the materials without ester substituents. The high hole mobilities of the recently investigated discotic liquid crystals of the hexaalkyloxytriphenylene-type are restricted to the very small temperature range of their mesophase. It is extended substantially by substitution of one ester group, as this hinders crystallization and results in glass formation. It is found that the substitution of an ester group alters the temperature and field dependence of the mobility completely. In the ester substituted compounds the mobility µ is not independent of temperature but follows a ln µ∝1/T2 law. We attribute this to the dipole moment of the ester group which causes random fluctuations in the local electric field and leads to disorder dominated charge carrier hopping as the prevailing transport mechanism.