Ultra-low lattice thermal conductivity and promising thermoelectric figure of merit in borophene via chlorination  

作　　者：Jia He Yanxiao Hu Dengfeng Li Jie Chen 

机构地区：[1]Center for Phononics and Thermal Energy Science,China–EU Joint Lab for Nanophononics,School of Physics Science and Engineering,Tongji University,Shanghai 200092,China [2]School of Science,Chongqing University of Posts and Telecommunications,Chongqing 400065,China

出　　处：《Nano Research》2022年第4期3804-3811,共8页纳米研究（英文版）

基　　金：This project is supported in part by the grants from the National Natural Science Foundation of China(Nos.12075168 and 11890703);the Science and Technology Commission of Shanghai Municipality(No.19ZR1478600).

摘　　要：Monolayer boron-based materials are of current interests due to its polymorphism.Herein,motivated by the recent experimental synthesis of semiconducting hydrogenatedαʹ-borophene and the regulation of the physical properties in layered materials by surface functionalization,we study the thermal and electronic properties ofαʹ-borophene with three different types of gas functional groups(H,F,and Cl)based on first-principles and Boltzmann transport theory.It is found thatαʹ-borophene can be well stabilized by fluorination and chlorination and maintain the semiconductor nature.More interestingly,when hydrogen is replaced with fluorine or chlorine,the lattice thermal conductivity changes from 24.3 to 5.2 or 0.73 W/(m·K)along armchair direction at 300 K,exhibiting a huge reduction by two orders of magnitude.The main reason is the decrease of both phonon group velocities and acoustic phonon relaxation time resulting from the strong phonon mode softening due to the weaken B-B bond strength and heavier atomic mass of fluorine and chlorine.Consequently,the chlorinatedαʹ-borophene exhibits a high thermoelectric figure of merit~2 at 300 K along armchair direction.Our study illustrates the importance of the modulation of transport properties by gas functional groups,which may promote the thermoelectric application of boron-based materials.

关 键 词：borophene thermal transport thermoelectric figure of merit density functional theory gas atom functionalization 

分 类 号：O73[理学—晶体学]