The Mobility and Decay Kinetics of Charge Carriers in Discotic Hexabenzocoronenes
The Mobility and Decay Kinetics of Charge Carriers in Discotic Hexabenzocoronenes
复制标题
盘状六苯并酮中载流子的迁移率和衰变动力学
DOI：
10.1002/adfm.200400096
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发表时间：
2004
影响因子：
19
通讯作者：
J. Warman
中科院分区：
文献类型：
--
作者：
J. Piris;M. Debije;M. Watson;K. Müllen;J. Warman
利用脉冲辐射时间分辨微波电导率技术（PR - TRMC）测量了盘状六-周-六苯二氮杂蒽衍生物中载流子的迁移率和衰变动力学的温度依赖性。对于外消旋二甲基辛基和手性二甲基辛基，以及同分异构体正癸基取代衍生物，在固态(K) -液晶（Col）转变时，迁移率从0.5±0.1 cm2 V-1 s-1降低到0.30±0.05 cm2 V-1 s-1，支链化合物的转变温度降低约30℃。支链异构体在冷相中的电荷重组动力学相似，但外消旋化合物在K相中的衰变速度更快。不对称取代丁蒽醌（C4 AQ）衍生物的迁移率值比完全六烷基取代的化合物低2-3倍，这是由于后者材料中空穴和电子的核内迁移率相似，而前者材料中AQ部分的电子定位。电荷复合在C4 AQ衍生物的Col相中比在K相中要快几个数量级，这是由于AQ -基团在液晶相中的运动自由。
The temperature dependence of the mobility and decay kinetics of charge carriers in discotic hexa‐peri‐hexabonzocoronene derivatives has been measured using the pulse‐radiolysis time‐resolved microwave conductivity technique (PR‐TRMC). For both the racemic and chiral dimethyloctyl, and the isomeric n‐decyl substituted derivatives, the mobility decreases at the crystalline solid (K)–liquid crystalline (Col) transition from 0.5±0.1 to 0.30±0.05 cm2 V–1 s–1 with the transition temperature ca. 30 °C lower for the branched chain compounds. The charge recombination kinetics are similar for the branched chain isomers in the Col phase but a faster decay is found for the racemic compound in the K phase. The fact that the mobility values for an asymmetrically substituted butylanthraquinone (C4 AQ) derivative are a factor of 2–3 lower than for the fully hexakis‐alkyl substituted compounds is attributed to the similar intracore mobilities for holes and electrons in the latter materials and the electron localization on the AQ moiety in the former. Charge recombination is found to be orders of magnitude faster in the Col phase of the C4 AQ derivative than in the K phase, this is attributed to the motional freedom of the AQ– group in the liquid‐crystalline phase.