Intermolecular coupling enhanced thermopower in single-molecule diketopyrrolopyrrole junctions  

作　　者：Chao Fang Renad Almughathawi Qingqing Wu Wenqiang Cao Hang Chen Songjun Hou Yu Gu Hewei Zhang Yi Zhao Jueting Zheng Guopeng Li Jia Shi Junyang Liu Bing-Wei Mao Zitong Liu Colin J.Lambert Wenjing Hong 

机构地区：[1]State Key Laboratory of Physical Chemistry of Solid Surfaces,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China [2]Department of Physics,Lancaster University,Lancaster LA14YB,UK [3]State Key Laboratory of Applied Organic Chemistry(SKLAOC),College of Chemistry and Chemical Engineering,Lanzhou University,Lanzhou 730000,China [4]Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM),Xiamen 361005,China [5]Beijing National Laboratory for Molecular Sciences,Beijing 100190,China [6]Department of Physics,Faculty of Science,Taibah University,Madinah,Saudi Arabia

出　　处：《National Science Open》2023年第1期13-23,共11页国家科学进展（英文）

基　　金：supported by the National Natural Science Foundation of China(21722305,21933012,31871877);the National Key R&D Program of China(2017YFA0204902);Natural Science Foundation of Fujian Province(2018J06004);Beijing National Laboratory for Molecular Sciences(BNLMS202010 and BNLMS202005);the Fundamental Research Funds for the Central Universities(20720220020,20720220072,20720200068,20720190002);supported by the Engineering and Physical Sciences Research Council(EPSRC,EP/M014452/1,EP/P027156/1,and EP/N03337X/1);the European Commission,the Future and Emerging Technologies(FET)Open project 767187-QuIET and the European(EU)project Bac-to-Fuel.

摘　　要：Sorting out organic molecules with high thermopower is essential for understanding molecular thermoelectrics.The intermolecular coupling offers a unique chance to enhance the thermopower by tuning the bandgap structure of molecular devices,but the investigation of intermolecular coupling in bulk materials remains challenging.Herein,we investigated the thermopower of diketopyrrolopyrrole(DPP)cored single-molecule junctions with different coupling strengths by varying the packing density of the self-assembled monolayers(SAM)using a customized scanning tunneling microscope break junction(STM-BJ)technique.We found that the thermopower of DPP molecules could be enhanced up to one order of magnitude with increasing packing density,suggesting that the thermopower increases with larger neighboring intermolecular interactions.The combined density functional theory(DFT)calculations revealed that the closely-packed configuration brings stronger intermolecular coupling and then reduces the highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO)gap,leading to an enhanced thermopower.Our findings offer a new strategy for developing organic thermoelectric devices with high thermopower.

关 键 词：single-molecule electronics single-molecule junctions THERMOPOWER thermoelectric devices intermolecular coupling 

分 类 号：TB34[一般工业技术—材料科学与工程]