Underpotential deposition-mediated layer-by-layer growth of thin films

Patent metadata

Field	Value
Publication number	US-9689085-B2
Application number	US-201514689708-A
Country	US
Kind code	B2
Filing date	Apr 17, 2015
Priority date	Jun 23, 2008
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves electrochemically exchanging a mediating element on a substrate with a noble metal film by alternatingly sweeping potential in forward and reverse directions for a predetermined number of times in an electrochemical cell. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis.

First claim

The invention claimed is:

1. A method for controllably forming a submonolayer to multilayer thick noble metal film on a substrate comprising
electrochemically exchanging a mediating element on said substrate with a noble metal film by alternatingly sweeping potential in forward and reverse directions for a predetermined number of times in an electrochemical cell in which said substrate is immersed in an electrolyte solution comprising predetermined concentrations of cations of said mediating element and cations of said noble metal wherein said forward potential sweeps are initiated at a first potential which is greater than a bulk deposition potential of said mediating element and are stopped at a second potential at which the mediating element is displaced from said substrate and the noble metal is deposited on said substrate and wherein said reverse potential sweeps initiate at said second potential and end at said first potential and wherein said alternation of sweeps begins with sweeps in either said forward or said reverse potential directions.

2. The method of claim 1 wherein up to one monolayer of the mediating element is formed on the substrate prior to immersion in the electrolyte solution.

3. The method of claim 1 wherein the substrate comprises nanoparticles.

4. The method of claim 3 wherein the nanoparticles are core-shell nanoparticles.

5. The method of claim 4 wherein the core comprises a non-noble metal.

6. The method of claim 4 wherein the nanoparticles comprise a noble metal.

7. The method of claim 4 wherein the mediating element is a metal selected from the group consisting of Cu, Pb, Tl and Bi.

8. The method of claim 1 wherein the noble metal is Pt.

9. A method for controllably forming a submonolayer to multilayer thick Pt metal film on a substrate comprising
electrochemically exchanging a film of Cu on said substrate with a Pt film by alternatingly sweeping potential in forward and reverse directions for a predetermined number of times in an electrochemical cell in which said substrate is immersed in an electrolyte solution comprising predetermined concentrations of Cu cations and Pt cations wherein said forward potential sweeps are initiated at a first potential which is greater than a bulk deposition potential of the Cu cations and are stopped at a second potential at which Cu is displaced from said substrate and Pt is deposited on said substrate and wherein said reverse potential sweeps initiate at said second potential and end at said first potential and wherein said alternation of sweeps begins with sweeps in either said forward or said reverse potential directions.

10. The method of claim 9 wherein up to one monolayer of Cu is formed on the substrate prior to immersion in the electrolyte solution.

11. The method of claim 9 wherein the substrate comprise nanoparticles.

12. The method of claim 10 wherein the nanoparticles are core-shell nanoparticles.

13. The method of claim 12 wherein the core comprises a non-noble metal.

14. The method of claim 12 wherein the nanoparticles comprise a noble metal.

Assignees

• Brookhaven Science Ass Llc

Inventors

• Wang jia xu
• Adzic Radoslav R

Classifications

• B01J23/44

  Palladium · CPC title

• C25D21/12 Primary

  Process control or regulation (controlling or regulating in general G05) · CPC title

• B01J37/341

  making use of electric or magnetic fields, wave energy or particle radiation (use of flames, plasma or lasers B01J37/349) · CPC title

• C25D3/50

  of platinum group metals · CPC title

• H01M4/926

  on carbon or graphite · CPC title