Thermal transport in amorphous small organic materials: a mechanistic study

Zhou, Tian1; Li, Zhuhong1; Cheng, Yajuan2,3; Ni, Yuxiang4; Volz, Sebastian5; Donadio, Davide6; Xiong, Shiyun1; Zhang, Wenqing7; Zhang, Xiaohong1

2020-02-07

10.1039/c9cp05938e

PHYSICAL CHEMISTRY CHEMICAL PHYSICS   影响因子和分区

1463-9076

1463-9084

Understanding the thermal transport mechanisms in amorphous organic materials is of great importance to solve hot-spot issues in organic-electronics nanodevices. Here we studied thermal transport in two popular molecular electronic materials, N,N-dicarbazolyl-3,5-benzene (mCP) and N,N '-diphenyl-N,N '-di(3-methylphenyl)-(1,1 '-biphenyl)-4,4 ' diamine (TPD), in the amorphous state by molecular dynamics simulations. We found that due to the softness of organic materials, the low thermal conductivity of both systems can be greatly enhanced under pressure. Notably, in such systems, the convective term of heat flux provides an important contribution to thermal transport as it cross-correlates with the Virial term in the Green-Kubo formula. Mode diffusivity calculations reveal that low-frequency modes can contribute significantly to thermal transport in both mCP and TPD. By increasing the pressure, the sound velocity and relaxation time of such low-frequency modes can be enhanced, and a part of these modes converts from diffusons to propagons. The cooperation of these three effects is responsible for the strong pressure dependence of thermal transport in amorphous organic systems. Molecular pair heat flux calculations demonstrate that heat transfer mainly happens between pairs of molecules with distances below 1.4 nm. This work paves the way for the optimization of thermal transport in amorphous organic materials widely used in opto-electronics, e.g. as OLED and OPV.

SCI ; EI

英语

其他

Jiangsu Provincial Natural Science Foundation[BK20160308]

Chemistry ; Physics

Chemistry, Physical ; Physics, Atomic, Molecular & Chemical

WOS:000517561500042

ROYAL SOC CHEMISTRY

20200808186682

Amines ; Heat transfer ; Molecular dynamics ; Thermal conductivity

Thermodynamics:641.1 ; Heat Transfer:641.2 ; Physical Chemistry:801.4 ; Organic Compounds:804.1

CHEMISTRY

Web of Science

1.Soochow Univ, Jiangsu Key Lab Carbon Based Funct Mat & Devices, Inst Funct Nano & Soft Mat FUNSOM, 199 Renai Rd, Suzhou 215123, Jiangsu, Peoples R China
2.Soochow Univ, Coll Chem Chem Engn & Mat Sci, Key Lab Organ Synth Jiangsu Prov, Suzhou 215123, Peoples R China
3.Soochow Univ, Coll Chem Chem Engn & Mat Sci, State & Local Joint Engn Lab Novel Funct Polymer, Suzhou 215123, Peoples R China
4.Southwest Jiaotong Univ, Sch Phys Sci & Technol, Key Lab Adv Technol Mat, Minist Educ China, Chengdu 610031, Peoples R China
5.Univ Tokyo, Inst Ind Sci, LIMMS CNRS IIS UMI2820, Meguro Ku, 4-6-1 Komaba, Tokyo 1538505, Japan
6.Univ Calif Davis, Dept Chem, One Shields Ave, Davis, CA 95616 USA
7.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China

Zhou, Tian,Li, Zhuhong,Cheng, Yajuan,et al. Thermal transport in amorphous small organic materials: a mechanistic study[J]. PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2020,22(5):3058-3065.

Zhou, Tian.,Li, Zhuhong.,Cheng, Yajuan.,Ni, Yuxiang.,Volz, Sebastian.,...&Zhang, Xiaohong.(2020).Thermal transport in amorphous small organic materials: a mechanistic study.PHYSICAL CHEMISTRY CHEMICAL PHYSICS,22(5),3058-3065.

Zhou, Tian,et al."Thermal transport in amorphous small organic materials: a mechanistic study".PHYSICAL CHEMISTRY CHEMICAL PHYSICS 22.5(2020):3058-3065.