The structures of self-assembled monolayers(SAMs)of short(methyl)and long(hexyl)chain alkyl thiols on the clean gold(111)surface were modeled using for the Au–S interactions either the reactive ReaxFF potential or th...The structures of self-assembled monolayers(SAMs)of short(methyl)and long(hexyl)chain alkyl thiols on the clean gold(111)surface were modeled using for the Au–S interactions either the reactive ReaxFF potential or the well-known nonreactive Morse potential,while for the Au–Au interactions either the ReaxFF potential or an embeddedatom method(EAM).Analysis of the molecular dynamics(MD)trajectories of possible SAM structures suggests that disordering of interfacial Au atoms is definitely driven by the gold–sulphur interactions.Our MD results reveal a novel structure where two methanethiol molecules are bound to a gold adatom that has been lifted from the surface at 300 K,and the same kind of RS–Au–SR motif was also observed for hexanethiol at 600 K but not at 300 K.What is more,the above motif is only observed for the reactive ReaxFF potential.Moreover,these results are in clear agreement with recent experiments and more costly first principles-based MD simulations.These findings strongly support the use of reactive potentials such as ReaxFF for gathering an accurate description of Au–S interactions in inexpensive classical MD simulations.展开更多
Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly....Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.展开更多
The photocurrent created by the TiO 2 nanoporous film electrode modified by octadecanethiol(18SH) self-assembled monolayer(SAM) was found to be 1 95 times greater than that without modification as shown by cyclic volt...The photocurrent created by the TiO 2 nanoporous film electrode modified by octadecanethiol(18SH) self-assembled monolayer(SAM) was found to be 1 95 times greater than that without modification as shown by cyclic voltammetry(CV). Meanwhile the maximum adsorbed peak has extended to the infrared range for about 20 nm. The formation of SAM was also assured with CV and small amplitude isosceles triangle potential methods, where the sensitization of SAM on the oxidation of CH 3OH on the TiO 2 nanoporous film electrode could be observed clearly. The results elucidated that the increased photocurrent by modification of octadecanethiol could not be simply attributed to the oxidation of octadecanethiol or ethanol. The results also implied that the application of SAM would be practicable in the sensitization of TiO 2 nanoporous film electrode in solar cell area.展开更多
基金Ⅴ. ACKN0WLEDGMENTS
This work was supported by the National Natural Science Foundation of China （No.20473078） and The Ph.D. Programs Foundation of Ministry of Education of China （No.20020358061）.
文摘B3LYP/LanL <SUB>1</SUB > MB 和 B3LYP/LanL <SUB>2</SUB > 为与为 S， C 和 H 原子的 6-31G (d) 基础集合一起的 Ag 原子的 DZ 方法被用来优化几何学并且计算精力为(SCH <SUB>3</SUB>)<SUB > m </SUB > Ag <SUB>20</SUB>(m=1-4 ) 分别地。一个单个分子的吸附精力(SCH <SUB>3</SUB>)<SUB > Ag <SUB>20</SUB> 和分子间的调停底层的相互作用精力上的 m </SUB>(m=1-4 ) 被评估。结果表明在单个分子的吸附精力和调停底层的分子间的相互作用精力之间有一种比例的关系。结果品质上证明为精力由我们以前建议了的调停底层的相互作用的半实验的表示与密度的结果一致功能的理论。
基金supported by Project PTDC/CTMNAN/112241/2009Grant No.Pest−C/EQB/LA0006/2011+2 种基金financed by FEDER through COMPETE-Programa Operacional Factores de CompetitividadeFCT-Funda¸cão para a Ciência e a Tecnologia.J.L.C.Fajin acknowledges FCT for the grant SFRH/BPD/64566/2009 cofinancedthe Fundo Social Europen(FSE).
文摘The structures of self-assembled monolayers(SAMs)of short(methyl)and long(hexyl)chain alkyl thiols on the clean gold(111)surface were modeled using for the Au–S interactions either the reactive ReaxFF potential or the well-known nonreactive Morse potential,while for the Au–Au interactions either the ReaxFF potential or an embeddedatom method(EAM).Analysis of the molecular dynamics(MD)trajectories of possible SAM structures suggests that disordering of interfacial Au atoms is definitely driven by the gold–sulphur interactions.Our MD results reveal a novel structure where two methanethiol molecules are bound to a gold adatom that has been lifted from the surface at 300 K,and the same kind of RS–Au–SR motif was also observed for hexanethiol at 600 K but not at 300 K.What is more,the above motif is only observed for the reactive ReaxFF potential.Moreover,these results are in clear agreement with recent experiments and more costly first principles-based MD simulations.These findings strongly support the use of reactive potentials such as ReaxFF for gathering an accurate description of Au–S interactions in inexpensive classical MD simulations.
文摘Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.
文摘The photocurrent created by the TiO 2 nanoporous film electrode modified by octadecanethiol(18SH) self-assembled monolayer(SAM) was found to be 1 95 times greater than that without modification as shown by cyclic voltammetry(CV). Meanwhile the maximum adsorbed peak has extended to the infrared range for about 20 nm. The formation of SAM was also assured with CV and small amplitude isosceles triangle potential methods, where the sensitization of SAM on the oxidation of CH 3OH on the TiO 2 nanoporous film electrode could be observed clearly. The results elucidated that the increased photocurrent by modification of octadecanethiol could not be simply attributed to the oxidation of octadecanethiol or ethanol. The results also implied that the application of SAM would be practicable in the sensitization of TiO 2 nanoporous film electrode in solar cell area.
