Preparation,Rectification And Ionic Conductivity Of Doped Metal Chalcogenides

With the rapid development of information technology in modern society,molecular rectifiers are the basic elements for implementing molecular electronic circuits.Almost all devices with logic functions can be realized with molecular rectifiers.Molecular rectifiers are based on molecular electronics and are designed with multiple or single organic small molecules as their host materials.However,they have such defects as unstable performance,poor repeatability,low rectification ratio,unclear mechanism and uncontrollability.The research on the rectification effect of ionic organic-inorganic hybrid materials has rarely been reported so far.In this dissertation,three examples of metal chalcogenides FJU-68-n([enH]0.5Cu1.5-xAgxSn0.5S2,en=ethylenediamine,Cu/Ag ratio n=(1.5-x)/x=2.2,2.3 or 2.4)were synthesized by solvothermal method.FJU-68-n is a two-dimensional layered material supported by an ethylenediamine monovalent cation.By changing the content of different reactants,the Cu/Ag ratio in the product can be easily controlled.The single-crystal rectification and ionic conductor performance tests of the three compounds of the FJU-68-n along the three crystal axes,a,b,c,show that the volt-ampere characteristics of the doped FJU-68-n exhibit rectification effects.No rectification effect was observed for undoped[enH]0.5Cu1.5Sn0.5S2.Increasing the Cu/Ag ratio will systematically increase the ionic conductivity and the rectification ratio in the a-axis direction of the crystal axis.The Cu/Ag ratio increases from 2.2 to 2.4,and the rectification ratio changes from 14 to 107 which increase 8 times;The ionic conductivity changed from 4.80×X10-4 to 4.80×10-2 S cm-1 at 80 ?,which increase about 100 times.However,adjusting the Cu/Ag ratio has little effect on the ionic conductivity and the rectification ratio in the b or c direction of the crystal axis.These indicate that the structural asymmetry and disordering caused by doping of metal ions is the main reason for the rectification effect of FJU-68.The rectification ratio can be controlled by adjusting the migration of copper and silver ions in the layer along the a-axis.This provides a new idea for the design of semiconductor rectifier devices.In this paper,three examples of metal chalcogenide compound FJU-69([1,2-dapH]0.5Cu1.5-xAgxSn0.5S2,1,2-dapH=1,2-diaminopropane,Cu/Ag ratio n=(1.5-x)/x=2.2,2.3 or 2.4)were synthesized by using 1,2-diaminopropane as solvent instead of ethylenediamine.Compared with FJU-68,the conductivity of the material was reduced by many times under the same conditions.It was demonstrated that the solvent has an important influence on the properties of the material.In addition,this article also synthesized a simple sulfur compound FJU-70,and tested its conductivity,and it is hoped that it as the basic structural unit,and then synthesized a new chalcogenide with multiple metals.