光-电双激发模式下有机半导体中的激子行为及相关磁效应

项目名称： 光-电双激发模式下有机半导体中的激子行为及相关磁效应

项目编号： No.11204247

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 雷衍连

作者单位： 西南大学

项目金额： 26万元

中文摘要： 有机半导体中的磁效应是当前有机电子学研究领域中的热点问题之一。尽管大量研究表明有机半导体器件中的电流和发光强度在外加磁场作用下会表现出明显的磁响应，但是对其所涉及的微观机制目前存在较大争议，特别是激子在有机磁效应中所扮演的具体角色还不确定。针对这一科学问题，本项目采用光-电双激发模式，实现对激子和载流子的有效控制，重点研究光-电双激发模式下有机磁效应出现以下三种新现象的物理起源：即单层器件磁电导效应在低场附近出现"W"型新峰位、双层器件磁电导的高场部分在正负偏压下出现相反变化趋势以及掺杂器件中正负磁电导的转变，具体讨论有机半导体中的激子行为在上述磁效应产生过程中所起的作用。本项目将构建有机磁效应与激子演变过程之间的关联，建立和完善有机磁效应的微观机制，并确定出影响有机磁效应的关键因素，为开发集磁-光-电各项性能于一体的新型有机功能器件奠定基础，因此具有明显的研究价值和较好的应用前景。

中文关键词： 有机磁效应；有机半导体；激子；激基复合物；有机发光二极管

英文摘要： Magnetic field effects (MFEs) in organic semiconductor are among the hot topics in modern organic electronics. Many studies have demonstrated that the current and electroluminescence of the organic devices show pronounced magnetic field responses when the devices are submitted to external magnetic field. However, many critical issues in the MFEs are still not clear, in particular, the role of the excitons on MFEs. In this project we intend to resolve this issue by applying a novel experimental method, called Synchronous Optical and Electrical Excitation (SOEE) mode, in which the number and distribution of exctions and current passing through the devices can be controlled separatedly and effectively by varying the intensity and wavelength of excitation light and by changing the amplitude and direction of drive voltage, respectively. Then, we plan to study the physical origin of three interesting findings obtained in the feasibility studies under SOEE mode. The three findings are (i) magnetoconductance (MC) with 'W' shape at low field (B<200 mT) scale in single layer devices, (ii) different field dependence of MC at high field (B>50 mT) scale in double layer deveices, and (iii) sign invension of MC in doped devices, respectively. The exciton behavior and the role of exciton on the above MFEs under SOEE mode will b

英文关键词： organic magnetic field effects；organic semiconductor；exciton；exciplex；organic light-emitting diodes