有机半导体激发态的量子调控  

Excited state quantum modulations in organic semiconductors

作　　者：高琨[1] 秦伟[1] 郝晓涛 解士杰[1] Kun Gao;Wei Qin;Xiaotao Hao;Shijie Xie(State Key Laboratory of Crystal Materials,School of Physics,Shandong University,Jinan 250100,China)

机构地区：[1]山东大学物理学院,晶体材料国家重点实验室,济南250100

出　　处：《科学通报》2021年第16期1983-1997,共15页Chinese Science Bulletin

基　　金：国家自然科学基金(11974212,61631166001,11774203,11674195);山东省自然科学基金(ZR2019ZD43)资助。

摘　　要：有机半导体激发态具有多样性和独特性,这使得有机器件呈现出丰富而特有的物理现象.从根本来说,有机器件的功能过程与这些激发态的动力学演化密切相关,包括产生、弛豫、输运、复合及相互转化等.目前,多种有机器件虽已被研制成功,但其功能机制中仍有许多未解之谜,其中激发态研究是重中之重,是有机半导体物理及器件研究的重心.多年来,我们基于有机半导体激发态独特的性质、相互作用及界面过程,围绕其功能器件中的关键科学问题,通过实验和理论相结合的手段,对其内部激发态的量子效应和调控开展了多尺度的深入研究.本文将结合相关研究背景对我们在有机光伏效应和有机自旋效应两方面的一些典型工作做简要介绍.Organic semiconductors are formed by coupling organic molecules withπ-conjugated structure through van der Waals interactions.Different from traditional inorganic semiconductors,such as silicon,the core element of organic semiconductors is carbon atom.Generally,in aπ-conjugated organic molecule,carbon atoms are polymerized by sp or sp2 hybridization,forming small molecules or polymers due to the molecular size.Taking the polymer cis-polyacetylene as an example,each carbon atom has three 2sp2 hybrid orbitals in a plane and one 2pz orbital orthogonal to this plane.The 2sp2 orbitals give rise to threeσ-bonds,two of which are formed with neighboring carbons and one with a hydrogen.The electron in the 2pz orbital of one carbon atom will be paired with the electron in the neighboring carbon’s 2pz orbital,such that this electron can be delocalized along the chain,denoted asπ-electron.For such an organic molecule,according to the Peierls instability,it will be dimerized and form a single-double bond alternation lattice structure,behaving in a semiconductor character.Through doping,the conductivity of organic molecules can be greatly improved and become good conductors.This is the reason why the functional properties of organic molecules first attracted great attention in the 1970s,by which,Heeger,MacDiarmid and Shirakawa won the 2000 Nobel Prize in Chemistry.When organic molecules form solids,the packing of molecules will ultimately determine their functional properties and applications,such as organic polymer films and organic small molecule crystals.Over the past few decades,due to the flexibility and ease of processing,organic semiconductors have become very promising materials in functional devices,such as field-effect transistors,light-emitting diodes,solar cells,as well as organic spin valves.In general,the functional processes of these organic devices are closely related to the quantum dynamics of the formed excited states,including soliton,polaron,bipolaron,exciton,biexciton,charge transfer state,and trion,

关 键 词：有机半导体 激发态 光电器件 自旋效应 多场调控 手性结构 

分 类 号：TN304[电子电信—物理电子学]