Electronic excitations and metal-insulator transition in poly(3-hexylthiophene) organic field-effect transistors
Electronic excitations and metal-insulator transition in poly(3-hexylthiophene) organic field-effect transistors
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DOI：
10.1103/physrevb.75.045307
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发表时间：
2006-11
影响因子：
3.7
通讯作者：
N. Sai;Z. Q. Li;M. Martin;D. Basov;M. Ventra
中科院分区：
文献类型：
--
作者：
N. Sai;Z. Q. Li;M. Martin;D. Basov;M. Ventra
本文对聚3-己基噻吩（P3 HT）的电荷注入进行了全面的理论和实验研究，计算了P3 HT中极化子和双极化子晶格对应的光吸收频率，确定了该体系中最可能发生金属-绝缘体转变的情形。我们还分析了三种可能的情况下，一个第一或asecond阶金属-绝缘体转变可以发生在掺杂P3 HT的electronicexcitation。这些理论方案进行了比较，从P3 HT薄膜场效应晶体管（FET）的红外吸收光谱的数据。我们的测量和理论预测表明，P3 HT FET中的电荷诱导局域态是双极化子，实验中获得的最高掺杂能级接近一阶金属-绝缘体跃迁所需的能级。
We carry out a comprehensive theoretical and experimentalstudy of charge injection in poly(3-hexylthiophene) (P3HT) to determinethe most likely scenario for metal-insulator transition in this system.Wecalculate the optical-absorption frequencies corresponding to a polaronand a bipolaron lattice in P3HT. We also analyze the electronicexcitations for three possible scenarios under which a first- or asecond-order metal-insulator transition can occur in doped P3HT. Thesetheoretical scenarios are compared with data from infrared absorptionspectroscopy on P3HT thin-film field-effect transistors (FETs). Ourmeasurements and theoretical predictions suggest that charge-inducedlocalized states in P3HT FETs are bipolarons and that the highest dopinglevel achieved in our experiments approaches that required for afirst-order metal-insulator transition.