High surface coverage of a self-assembled monolayer by in situ synthesis of palladium nanodeposits

Abstract

Nascent metal|monolayer|metal devices have been fabricated by depositing palladium, produced through a CO-confined growth method, onto a self-assembled monolayer of an amine-terminated oligo(phenylene ethynylene) derivative on a gold bottom electrode. The high surface area coverage (85%) of the organic monolayer by densely packed palladium particles was confirmed by X-ray photoemission spectroscopy (XPS) and atomic force microscopy (AFM). The electrical properties of these nascent Au|monolayer|Pd assemblies were determined from the I-V curves recorded with a conductive-AFM using the Peak Force Tunneling AFM (PF-TUNA™) mode. The I-V curves together with the electrochemical experiments performed rule out the formation of short-circuits due to palladium penetration through the monolayer, suggesting that the palladium deposition strategy is an effective method for the fabrication of molecular junctions without damaging the organic layer.

Cancer-derived exosomes loaded with ultrathin palladium nanosheets for targeted bioorthogonal catalysis

“…The first challenge was to develop a method that allows loading a metal of choice into these vesicles without affecting the exosome targeting properties and preserves the metal's catalytic activity, since current biophysical techniques for loading exosomes with metallic nanostructures [51][52][53][54][55] can induce detrimental defects on the integrity of the exosome membrane. 56,57 Encouraged by prior success on the controlled growth of Pd nanosheets using carbon monoxide (CO) as a gaseous reducing agent under wet conditions, 58,59 a chemical methodology was investigated to generate Pd nanostructures directly inside exosomes. Figure 1A illustrates the stepwise production of Pd-Exo A549 (see full procedure in the Methods).…”

Interaction of synthetic and lignin-based sulfonated polymers with hydrophilic, hydrophobic, and charged self-assembled monolayers

“…For energy referencing, spectra were calibrated to the C1 line peak at 284.6 eV. 44 Data analysis and peak tting were conducted using ESCApe soware (V1.2.0.1325). The thickness of SAM-terminated surfaces on Au substrates was estimated by means of the attenuation of the Au 4f signal using the following eqn 3:…”

“…q is the photoelectron take-off angle, l is the effective attenuation length of the photoelectron, and d is the lm thickness. 44,45 The theoretical length values of SAM molecules used in this work have been attained from computational modeling Avogadro soware (V1.2.0) (written in C++ (Qt) with General Public License) and force eld model of MMFF94 (designed by Merck).…”

New routes to organometallic molecular junctionsviaa simple thermal processing protocol

“…The use of nanoparticle top contacts to give electrode | molecule | nanoparticle junctions has been widely explored, and the use of such nanoparticle junctions in the construction of a molecular-monlayer memory device has been recently described. 22 Strategies to these structures include direct deposition 23 or growth 24 of naked metal nanoparticles onto monolayers bearing an exposed functional group on the top surface capable of ligating to the nanoparticle, and electrochemical deposition of metal particle seeds on top of a monolayer prior to electroless metal in-fill. 25 As an alternative to electrochemical reduction, photochemical reduction of AuCl4or Ag + ions co-deposited on the top-surface of a Langmuir-Blodgett monolayer gives rise to high surface coverage of the monolayer by Au 26 or Ag 27 nanoparticles.…”