【作者】 郑小燕； 王冬； 帅志刚；

【Author】 Xiaoyan Zheng;D. Wang;Z. Shuai;MOE Key Laboratory of Organic Optoelectronics and Molecular Engineering,Department of Chemistry,Tsinghua University;

【机构】 清华大学化学系有机光电子与分子工程教育部重点实验室；

【摘要】 最近,实验报导通过溶液剪切法制备TIPS-P薄膜,可在很大程度上提高其空穴迁移率[1]。这里,我们通过非平衡分子动力学模拟、第一性原理计算和动态蒙特卡洛模拟相结合的多尺度理论方法,在核隧穿电荷跳跃模型基础上,研究了晶格形变对TIPS-P电荷传输性能的影响[2]。我们首先证实了实验上通过剪切形变得到的TIPS-P分子晶体中的一维电荷传输行为,其次揭示了TIPS-P分子晶体中晶格形变、分子堆积方式与载流子迁移率之间的构效关系,并进一步预测了各种晶格形变下载流子迁移率的变化,指出更有效地调控有机半导体电荷传输性能的方式。我们发现,将剪切应变和正应变相结合可使TIPS-P的电荷传输性能接近各向同性,且空穴迁移率提高至少一个数量级。我们的研究对晶格形变调控有机半导体电荷传输性能给出了深刻的理解,且理论方法可以应用到其它体系,对实验设计具有指导意义。更多还原

【Abstract】 Recently, solution-sheared thin-films of 6,13-bis(triisopropylsilylethynyl) pentacene(TIPS-P) with nonequilibrium single-crystal domains have been demonstrated to have much higher charge mobilities than unstrained ones(Nature 2011, 480, 504). In this work, by employing a multi-scale theoretical approach combining nonequilibrium molecular dynamics, first-principles calculations, and kinetic Monte Carlo simulations using charge transfer rates based on the tunneling enabled hopping model, we investigate charge transport properties of TIPS-P under various lattice strains. We first show that shear-strained TIPS-P indeed exhibits one-dimensional charge transport, which agrees with the experiment. Then, we find that either shear or tensile strain leads to mobility enhancement, but with strong anisotropy. And a combination of shear and tensile strains could not only enhance mobility, but also decrease anisotropy. By combining shear and tensile strains, we could realize almost isotropic charge transport in TIPS-P crystal with hole mobility improved by at least one order of magnitude.更多还原