(12) United States Patent (io) Patent No.: US 7,001,669 B2 Lu et al. (45) Date of Patent: Feb. 21,2006 (54) PROCESS FOR THE PREPARATION OF 6,395,230 B1 512002 Guerin et al. METAL-CONTAINING NANOSTRUCTURED 6,409,907 B1 612002 Braun et al. FILMS 6,423,411 B1 712002 Balkus, Jr. et al. 6,465,052 B1 1012002 wu Inventors: Yunfeng Lu, New Orleans, LA (US); 6,565,763 B1 * 512003 Asakawa et al. ............. 216156 (75) 6,805,972 B1 * 1012004 Erlebacher et al. ......... 4281613 Donghai Wang, New Orleans, LA (US) 200210034626 A1 312002 Liu, et al. 200210034827 A1 312002 Singh, et al. (73) Assignee: The Administration of the Tulane 200210055239 A1 512002 Tuominen, et al. Educational Fund, New Orleans, LA 200210102396 A1 812002 MacDougall, et al. (US) 200210118027 A1 812002 Routkevitch, et al. 200210119455 A1 812002 Chan ( * ) Notice: Subject to any disclaimer, the term of this 200210138049 A1 912002 Allen, et al. patent is extended or adjusted under 35 200210146745 A1 1012002 Natan, et al. U.S.C. 154(b) by 133 days. (Continued) (21) Appl. No.: 10/328,631 FOREIGN PATENT DOCUMENTS (22) Filed: Dec. 23, 2002 EP 1 123 753 A2 812001 (Continued) (65) Prior Publication Data OTHER PUBLICATIONS US 200410118698 A1 Jun. 24, 2004 Michael H. Huang, et al., “Ag Nanowire Formation Within (51) Int. C1. Mesoporous Silica,” Chem. Commun., pp. 1063-1064 B32B 5/00 (2006.0 1) (2000). (52) U.S. C1. .................... 4281613; 4281304.4; 1481430 (Continued) (58) Field of Classification Search ................ 4281613, 4281605, 608,304.4; 205167,75,224; 1481518, Primary Examiner-John J. Zimmerman 1481537,430 (74) Attorney, Agent, or Firm-Olson & Hierl, Ltd See application file for complete search history. (57) ABSTRACT (56) References Cited Metal-containing nanostructured films are prepared by elec- U.S. PATENT DOCUMENTS trodepositing a metal-containing composition within the 2,616,165 A * 1111952 Brennan ..................... 4281613 pores of a mesoporous silica template to form a metal- 4,077,853 A * 311978 Coll-Palagos ................ 205175 containing silica nanocomposite. The nanocomposite is 4,977,038 A * 1211990 Sieradzki et al. ........... 4281610 annealed to strengthen the deposited metal-containing com- 5,849,215 A 1211998 Gin et al. position. The silica is then removed from the nanocompos- 6,129,901 A 1012000 Moskovits et al. ite, e.g., by dissolving the silica in an etching solution to 6,136,704 A 1012000 Maya provide a self-supporting metal-containing nanostructured 6,187,165 B1 212001 Chien et al. film. The nanostructured films have a nanowire or nanomesh 6,203,925 B1 312001 Attard et al. architecture depending on the pore structure of the meso- 6,218,050 B1 412001 Yoon et al. 6,231,744 B1 512001 Ying et al. porous silica template used to prepare the films. 6,334,856 B1 112002 Allen et al. 6,365,266 B1 412002 MacDougall et al. 3 Claims, 10 Drawing Sheets US 7,001,669 B2 U.S. PATENT DOCUMENTS Yunfeng Lu, et al., “Evaporation-Induced Self-Assembly of Hybrid Bridged Silsesquioxane Film and Particulate 200210158342 A1 1012002 Tuominen, et al. Mesophases With Integral Organic Functionality,” J. Am. 200310075445 A1 * 412003 Woudenberg et al. ....., 2041451 Chem. SOC.,122 (22), pp. 5258-5261 (2000). 200410261500 A1 * 1212004 Ng et al. ................... 73131.05 N. A. Melosh, et al., “Molecular and Mesoscopic Structures FOREIGN PATENT DOCUMENTS of Transparent Block Copolymer-Silica Monoliths,” Macromolecules, 32 (13), pp. 4332-4342 (1999). EP 0 993 512 B1 812002 Wen-Hua Zhang, et al., “Synthesis and Characterization of wo WO98148456 1011998 Nanosized ZaS Confined in Ordered Mesoporous Silica,” wo WO 99100536 111999 Chem. Mater:, 13 (2) pp. 648-654 (2001). wo WO 99164580 1211999 Martinus H. V. Werts, et al., “Nanometer Scale Patterning of wo WO 00114307 312000 Langmuir-Blodgett Films of Gold Nanoparticles by Electron wo WO 01125510 A1 412001 Beam Lithography,” Nano Letters, 2 (l), pp. 43-47 (2002). wo WO 02142201 A1 512002 FrCdCric Favier, et al., “Hydrogen Sensors and Switches WO WO 021080280 A1 1012002 from Electrodeposited Palladium Mesowire Arrays,” SCZ- OTHER PUBLICATIONS ENCE, 293 (5538), pp. 2227-2231 (Sep. 21, 2001). J. I. Pascual, et al., “Properties of Metallic Nanowires: From G. Schider, et al., “Optical Properties of Ag and Au Nanow- Conductance Quantization to Localization,” SCZENCE, 267 ire Gratings,” Journal ofApplied Physics, 90 (8), pp. 3825- (5205), pp. 1793-1795 (Mar. 24, 1995). 3830 (Oct. 15, 2001). Sheila R. Nicewarner-Pefia, et al., “Submicrometer Metallic Kyung-Bok Lee, et al., “Size-Controlled Synthesis of Pd Barcodes,” SCZENCE, 294 (5540), pp. 137-141 (Oct. 5, Nanowires Using a Mesoporous Silica Template via Chemi- 2001). cal Vapor Infiltration,”Advanced Materials, 13 (7), pp. 517- T. Thurn-Albrecht, et al., “Ultrahigh-Density Nanowire Ar- 520 (Apr. 4, 2001). rays Grown in Self-Assembled Dibock Copolymer A. J. Yin, et al., “Fabrication of Highly Ordered Metallic Templates,” SCZENCE, 290 (5499), pp. 2126-2129 (Dec. 15, Nanowire Arrays by Electrodeposition,” Applied Physics 2000). Letters, 79 (7), pp. 1039-1041 (Aug. 13, 2001). Michael P. Zach, et al., “Molybdenum Nanowires by Yong-Jin-HAN, et al., “Preparation of Noble Metal Electrodeposition,” SCZENCE, 290 (5499), pp. 2120-2123 Nanowires Using Hexagonal Mesoporous Silica SBA-15,” (Dec. 15,-2000). Chem. Mater:, 12 (8), pp. 2068-2069 (2000). George S. Attard, et al., “Mesoporous Platinum Films from I. A. Aksay, et al., “Biomimetic Pathways for Assembling Lyotropic Liquid Crystalline Phases,” SCZENCE, 278 Inorganic Thin Films,” SCZENCE, 273, pp. 892-898 (Aug. (5339), pp. 838-840 (Oct. 31, 1997). 16, 1996). Yunfeng, Lu, et al., Continuous Formation of Supported Anne Galarneau, et al., “True Microporosity and Surface Cubic and Hexagonal Mesoporous Films by Sol-Gel Dip- Area of Mesoporous SBA-15 Silicas as a Function of Coating, NATURE, 389 (6649),pp. 364-368 (Sep. 25,1997). Synthesis Temperature,” Langimuir, 17 (26), pp. 8328-8335 (2001). * cited by examiner US. Patent Feb. 21,2006 Sheet 1 of 10 US 7,001,669 B2 100 I 4 Fig. 7 US. Patent Feb. 21,2006 Sheet 2 of 10 US 7,001,669 B2 B Fig. 2 US. Patent Feb. 21,2006 Sheet 3 of 10 US 7,001,669 B2 Fig. 3 US. Patent Feb. 21,2006 Sheet 4 of 10 US 7,001,669 B2 Fia. 4 US. Pate nt Feb. 21,2006 Sheet 5 of 10 US 7,001,669 B2 2 3 4 5 2 Theta /degree Fig. 5 2 3 4 5 2 Theta I degree Fig. 6 US. Patent Feb. 21,2006 Sheet 6 of 10 US 7,001,669 B2 US. Patent Feb. 21,2006 Sheet 7 of 10 US 7,001,669 B2 US. Patent Feb. 21,2006 Sheet 8 of 10 US 7,001,669 B2 US. Patent Feb. 21,2006 Sheet 9 of 10 US 7,001,669 B2 US. Patent Feb. 21,2006 Sheet 10 of 10 US 7,001,669 B2 Fig. 77 US 7,001,669 B2 1 2 PROCESS FOR THE PREPARATION OF nanowires) having diameters of about 20 to 250 nanometers METAL-CONTAINING NANOSTRUCTURED and with lengths of about 1 to 10 millimeters. Nanostruc- FILMS tured materials which have been prepared by theses tem- plate-directed methods include nanowires of metals such as FIELD OF THE INVENTION s Au, Ag, Co, Cu, Ni, Pd, and Pt, semiconductors such as CdS, CdSe, InP, GaAs, and conductive polymers. This invention relates generally to processes for prepara- Colloidal semiconductor nanocrystals, passivated with tion of metal-containing nanostructured films. More particu- organic surfactants and size-selected to a very high degree, larly the invention relates to processes for the preparation of spontaneously precipitate out of solution and form three- metal and metal chalcogenide nanostructured films by elec- io dimensional arrays of nano-scale crystals (i.e., quantum trochemically depositing a metallic composition within a dots) In this configuration, the array of quantum dots form template. a quantum dot “crystal” or superlattice array. The strength of the electronic coupling between adjacent dots can be tuned BACKGROUND by variation of the organic passivating coating around the is dots. Electron transfer within such superlattice arrays results Thin films of metals and semiconductors (e.g., metal from inter-dot tunneling, which can limit the usefulness of chalcogenides such as CdSe and CdTe) are assuming vital such materials in solar cells, for example. roles in advanced technologies such as nanotechnology. Semiconductor thin films have been prepared by elec- Improved performance of thin-film-based devices, such as trodeposition. Reported electrodeposition of crystalline, nano-scale sensors, magnetic storage media, nano-scale 20 group 11-VI semiconductor compounds include, for optical devices, and the like, can often be achieved through example, galvanostatic electrodeposition of cadmium precise control of the film structure on an atomic to nanom- selenide from a dimethylsulfoxide (DMSO) solution of a eter scale. cadmium salt and elemental selenium at a temperature of Methods of film processing can be divided into two major about 185” C.; and potentiostatic deposition of cadmium categories: those carried out in a gas phase (i.e., “dry zs selenide from an aqueous solution of a cadmium salt and processes”) and those carried out in a liquid phase (i.e., “wet selenous acid at a pH of about 2-2.5. Electrochemical processes”). The dry processes include, for example, tech- atomic layer epitaxy has also been used to deposit semicon- niques such as vacuum evaporation, chemical vapor depo- ductor thin films. Group 111-V semiconductor compounds sition (CVD), molecular beam epitaxy (MBE), and sputter- have been electrodeposited from aqueous solutions or mol- ing. These techniques generally require high vacuum and/or 30 ten salts. high temperatures to produce gaseous precursor molecules Mesoporous silica has also been utilized as a template or atoms, which are then condensed onto a substrate to form material for preparation of nanostructured materials.