title: Array of molecularly mediated thin film assemblies of nanoparticles: correlation of vapor sensing with interparticle spatial properties.
abstract: The ability to tune interparticle spatial properties of nanoparticle assemblies is essential for the design of sensing materials toward desired sensitivity and selectivity. This paper reports findings of an investigation of molecularly mediated thin film assemblies of metal nanoparticles with controllable interparticle spatial properties as a sensing array. The interparticle spatial properties are controlled by a combination of alpha,omega-difunctional alkyl mediators (X-(CH(2))(n)-X) such as alkyl dithiols, dicarboxylate acids, and alkanethiol shells capped on nanoparticles. Alkanethiolate-capped gold and gold-silver alloy nanoparticles (2-3 nm) were studied as model building blocks toward the thin film assemblies, whereas the variation of alkyl chain length manipulates the interparticle spacing. The thin films assembled on an interdigitated microelectrode array platform are characterized for determining their responses to the sorption of volatile organic compounds (VOCs). The correlation between the response sensitivity and the interparticle spacing properties revealed not only a clear dependence of the sensitivity on alkyl chain length but also the occurrence of a dramatic change of the sensitivity in a region of chain length for the alkyl mediator comparable with that of the capping alkyl chains. This finding reflects a balance between the interparticle chain-chain cohesive interdigitation and the nanostructure-vapor interaction which determines the relative change of the electrical conductivity of the inked nanoparticle thin film in response to vapor sorption. The results, along with statistical analysis of the sensor array data in terms of sensitivity and selectivity, have provided important insights into the detailed delineation between the interparticle spacing and the nanostructured sensing properties.
authors.affiliation: Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, USA.
authors.forename: Lingyan
authors.initials: L
authors.lastname: Wang
authors.forename: Xiajing
authors.initials: X
authors.lastname: Shi
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Kariuki
authors.forename: Mark
authors.initials: M
authors.lastname: Schadt
authors.forename: Guannan Roger
authors.initials: GR
authors.lastname: Wang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Rendeng
authors.forename: Jeongku
authors.initials: J
authors.lastname: Choi
authors.forename: Jin
authors.initials: J
authors.lastname: Luo
authors.forename: Susan
authors.initials: S
authors.lastname: Lu
authors.forename: Chuan-Jian
authors.initials: CJ
authors.lastname: Zhong
mesh_terms: D000497:Alloys / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D009930:Organic Chemicals / Q000032:analysis* / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013816:Thermodynamics; D014835:Volatilization
chemical_list: D000497:Alloys; D002264:Carboxylic Acids; D009930:Organic Chemicals; D013438:Sulfhydryl Compounds; D012834:Silver; D006046:Gold