Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen  

作　　者：Ahmad Hamdan Hiba Kabbara Cedric Noel Jaafar Ghanbaja Abdelkrim Redjaimia Thierry Belmonte 

机构地区：[1]Universite de Lorraine,lnstitutJean tamour,UMR CNRS 7198,Nancy F-54042,France [2]CNRS,lnstitutJean Lamour,UMR CNRS 7198,Nancy F-54042,France

出　　处：《Particuology》2018年第5期152-159,共8页颗粒学报（英文版）

摘　　要：A simple method to synthesise hexagonal lead sheets,which belong to the class of two-dimensional materials,is proposed.These objects are collected on a substrate located under two lead electrodes, between which nanosecond-pulsed spark discharges are ignited in liquid nitrogen.The hexagonal sheets are single crystals produced by gas phase condensation.Once nitrogen completely evaporates,the sheets change to PbO2by oxidation in air.The oxidation process induces stress that pleats the uppermost sheets or open cracks at the centre.The thickness of the individual objects typically varies from 4to 20nm.When the number of discharges is more than about 2000,in addition to sheets,two types of PbO2 sticks start to form:bundles composed of nanosticks (length 5p.m and diameter 50nm)and isolated sticks (length 20μm and diameter 500nm).These new nanostructures mainly form because of the way the discharge erodes the lead electrodes.Initially,anisotropic erosion driven by the orientation of the crystallographic planes of the lead crystals produces octahedra and nanosticks,and the nanosticks grow on the electrode surfaces as discharge proceeds.After about 2000discharges,the nanosticks are sufficiently long that they can be easily broken,probably by mechanical stress,and they fall onto the underlying substrate.

关 键 词：DISCHARGE in hquids Plasma-surface interaction Nanopamcles Liquid NITROGEN LEAD 

分 类 号：O3[理学—力学]