Liquid-Crystalline Perylene Diester Polymers with Tunable Charge-Carrier Mobility
Liquid-Crystalline Perylene Diester Polymers with Tunable Charge-Carrier Mobility
复制标题
DOI：
10.1002/adfm.201101694
复制
发表时间：
2011-12-06
影响因子：
19
通讯作者：
Thelakkat, Mukundan
中科院分区：
文献类型：
--
作者：
Muth, Mathis-Andreas;Carrasco-Orozco, Miguel;Thelakkat, Mukundan
报道了一类新的基于二萘嵌苯二酯苯并咪唑和二萘嵌苯二酯酰亚胺介晶的液晶半导体聚合物。采用氮氧自由基聚合法合成了两种高可溶性侧链聚合物聚（苝二酯苯并咪唑丙烯酸酯）（PPDB）和聚（苝二酯酰亚胺丙烯酸酯）（PPDI）。PPDB显示了n型半导体性能，通过根据MottGurney方程拟合空间电荷限制电流（SCLC）在二极管配置中获得的电子迁移率为3.2 x 10（-4）cm 2 V-1 s（-1）。有趣的是，PPDI优先表现为p型材料，空穴迁移率为1.5 × 10（-4）cm 2 V-1 s（-1），这归因于与PPDB相比，PPDI的电子缺陷较少。通过紫外-可见光谱和荧光光谱研究了其光学性质。与PPDI相比，由于PPDB的苯并咪唑单元导致的扩展的p-共轭系统导致可见光区中相当宽的吸收。还通过循环伏安法测定了聚合物的HOMO和LUMO能级;所得的能带隙对于PPDB为1.86 eV，对于PPDI为2.16 eV。通过差示扫描量热法、偏光显微镜和X射线衍射测量研究了其热行为和液晶性。结果表明，在很宽的温度范围内的聚合物的液晶顺序。这些热、电和光学性质使得二萘嵌苯侧链聚合物成为有机光致发光材料的有吸引力的材料。
New classes of liquid-crystalline semiconductor polymers based on perylene diester benzimidazole and perylene diester imide mesogens are reported. Two highly soluble side-chain polymers, poly(perylene diester benzimidazole acrylate) (PPDB) and poly(perylene diester imide acrylate) (PPDI) are synthesized by nitroxide-mediated radical polymerization (NMRP). PPDB shows n-type semiconductor performance with electron mobilities of 3.2 x 10(-4) cm2 V-1 s(-1) obtained in a diode configuration by fitting the space-charge-limited currents (SCLC) according to the MottGurney equation. Interestingly, PPDI performs preferentially as a p-type material with a hole mobility of 1.5 x 10(-4) cm2 V-1 s(-1), which is attributed to the less electron-deficient perylene core of PPDI compared to PPDB. Optical properties are investigated by UV-vis and fluorescence spectroscopy. The extended p-conjugation system due to the benzimidazole unit of PPDB leads to a considerably broader absorption in the visible region compared to PPDI. HOMO and LUMO levels of the polymers are also determined by cyclic voltammetry; the resulting energy band-gaps are 1.86 eV for PPDB and 2.16 eV for PPDI. Thermal behavior and liquid crystallinity are studied by differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction measurements. The results indicate liquid-crystalline order of the polymers over a broad temperature range. These thermal, electrical, and optical properties make the perylene side-chain polymers attractive materials for organic photovoltaics.