【作者】 张亚媚； 林祥栋； 杨娥； 凌启淡；

【Author】 Yamei Zhang;Xiangdong Lin;E Yang;Qidan Ling;College of Chemistry and Chemical Engineering,Fujian Normal University;College of Materials Science and Engineering,Fujian Normal University;

【机构】 福建师范大学化学与化工学院； 福建师范大学材料科学与工程学院；

【摘要】 由于卟啉分子具有良好的化学和电子学性质以及基于Simmon方程^[1]中d_con和β_con值的考虑,我们通过采用密度泛函理论（DFT）与非平衡格林函数（NEGF）相结合的第一性原理方法研究了带烷链尾巴的卟啉和Zn-卟啉分子（C_nPH₂和C_nZnP（n=6¹1））分别连接于两金电极之间时的电子输运性质^[2],重点分析了C₁₁PH₂和C₁₁ZnP的Ⅰ-Ⅴ曲线特性和整流机制。结果发现,C_nPH₂系列分子结的开启电压都比较大,在1.5¹.8V范围内,它们的最大整流比为10¹;在C_nPH₂分子的卟啉环中加入过渡金属原子Zn,为C_nZnP系列分子结,其所有的Ⅰ-Ⅴ曲线都表现出类似传统的P-N结二极管的Ⅰ-Ⅴ曲线趋势,开启电压减小到0.8V附近,最大整流比达到到10³水平（¹100）。分析认为,这归因于Zn的加入使得"导电"分子ZnP部分的高能量的HOMOs能级就在低偏压下对电子连续共振遂穿提供了高效的通道,也就是提高Simmons方程中的"导电"共轭的电子遂穿参数β_con值我们的研究结果为实验上提升这种类型的单分子整流器提供一定的参考价值.更多还原

【Abstract】 In this paper,the porphyrin with alkyl chain and Zn porphyrin molecules(C_nZnP and C_nPH₂（n = 6 to 11） were connected in two gold electrodes,respectively,to study their electronic transport properties.The Ⅰ-Ⅴ characteristics and rectification mechanism of the C₁₁PH₂ and C₁₁ZnP were investigated and compared.The turn-on voltages of C_nPH₂ molecular junctions were in the range of 1.5¹.8V,and their max rectification ratio was only about 10.TheⅠ-Ⅴ curves of C_nZnP molecular junctions are similar to that of conventional P-N junction.However,the turn-on voltage was reduced to about 0.8V,and the max rectification ratio increased to 10³.The result indicates the addition of Zinc can make ZnP molecular junctions to be more conductive.It also reveals some high-energy HOMO levels which are under the low bias on electronic continuous resonance and thus can provide an efficient charge channel.更多还原