NANOSTRUCTURED FILMS AND RELATED METHODS

• US 20130161614A1
• Filed: 07/29/2011
• Published: 06/27/2013
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: Michael Snure
• Inventors: Tiwari, Ashutosh, Karmarkar, Makarand, Snure, Michael
• Granted Patent: US 9,057,144 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: C25D 11/02 Anodisation
• CPC Class Codes: C25D 11/26 of refractory metals or alloys based thereon
• CPC Class Codes: C25D 21/10 Agitating of electrolytes; Moving of racks
• CPC Class Codes: C25D 5/02 Electroplating of selected surface areas
• CPC Class Codes: H01G 9/2031 comprising titanium oxide, e.g. TiO2 H01G9/2036 takes precedence
• CPC Class Codes: H01G 9/2036 comprising mixed oxides, e.g. ZnO covered TiO2 particles
• CPC Class Codes: H01G 9/2059 comprising an organic dye as the active light absorbing material, e.g. adsorbed on an electrode or dissolved in solution
• CPC Class Codes: H01L 31/032 including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
• CPC Class Codes: H01M 14/005 Photoelectrochemical storage cells light sensitive devices H01G9/20, semiconductors sensitive to light H01L31/00
• CPC Class Codes: H10K 85/344 comprising ruthenium
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells

Abstract

Nanostructured films including a plurality of nanowells, the nanowells having a pore at the top surface of the film, the pore defining a channel that extends downwardly towards the bottom surface of the film are provided. Also provided are methods including exposing a growth substrate to an anodizing bath, applying ultrasonic vibrations to the anodizing bath, and generating a current through the anodizing bath to form the nanostructured film. The nanostructured films may be formed from TiO₂ and may be used to provide solid state dye sensitized solar cells having high conversion efficiencies.

Claims

1. A method of forming a nanostructured film, the method comprising:

exposing a growth substrate to an anodizing bath, the anodizing bath comprising an electrolyte solution,

applying ultrasonic vibrations to the anodizing bath, and

generating a current through the anodizing bath during the application of the ultrasonic vibrations to form the nanostructured film,

wherein the nanostructured film comprises a plurality of tubular nanowells, the tubular nanowells each having a pore at the top surface of the nanostructured film, the pore defining a channel that extends from the top surface of the nanostructured film downwardly towards the bottom surface of the nanostructured film.

2. The method of claim 1, wherein the growth substrate is a metal growth substrate and the nanostructured film is a metal oxide nanostructured film.

3. The method of claim 1, wherein the growth substrate is a titanium growth substrate and the nanostructured film is a titanium oxide nanostructured film.

4. The method of claim 1, wherein the amplitude of the ultrasonic vibrations is in the range of from about 1 μ

m to about 500 μ

m.

5. The method of claim 1, wherein the frequency of the ultrasonic vibrations is in the range of from about 15 kHz to about 2000 kHz.

6. The method of claim 1, wherein the current is generated by applying a voltage across the growth substrate and a cathode having a rough surface.

7. The method of claim 6, wherein the roughness of the cathode surface is in the range of from about 200 nm to about 5 μ

m.

8. The method of claim 1, wherein the amplitude of the ultrasonic vibrations is in the range of from about 1 μ

m to about 500 μ

m;

the frequency of the ultrasonic vibrations is in the range of from about 15 kHz to about 2000 kHz;

the concentration of the electrolyte is in the range from about 0.5 wt % to about 5 wt %;

the temperature of the anodizing bath is in the range from about 5°

C. to about 80°

C.;

the current is generated by a applying a voltage in the range of from about 10 V to about 60 V across the growth substrate and a cathode;

the distance between the growth substrate and the cathode is in the range of from about 2.5 cm to about 15 cm; and

the current is generated for a time period in the range of from about 20 minutes to 72 hours.

9. The method of claim 1, wherein one or more of the tubular nanowells have a tapered end.

10. A nanostructured film prepared according to the method of claim 1.

11. An optoelectronic device comprising:

a first electrode;

an active layer in contact with the first electrode, the active layer comprising a nanostructured film and dye molecules coated onto a surface of the nanostructured film;

solid electrolyte dispersed throughout the nanostructured film; and

a second electrode in contact with the active layer,

wherein the nanostructured film comprises a plurality of tubular nanowells, each having a pore at the top surface of the nanostructured film, the pore defining a channel that extends from the top surface of the nanostructured film downwardly towards the bottom surface of the nanostructured film.

12. The optoelectronic device of claim 11, wherein the tubular nanowells are oriented along an axis perpendicular to the plane of the nanostructured film.

13. The optoelectronic device of claim 11, wherein the tubular nanowells are arranged as an array.

14. The optoelectronic device of claim 11, wherein one or more of the tubular nanowells have a tapered end.

15. The optoelectronic device of claim 11, wherein the tubular nanowells are characterized by an average length in the range of from about 500 nm to about 1 mm;

an average width in the range of from about 110 nm to about 170 nm, an average pore diameter in the range of from about 100 nm to about 150 nm and an average wall thickness in the range of from about 5 nm to about 50 nm.

16. The optoelectronic device of claim 11, wherein the average distance between neighboring tubular nanowells is in the range of from about 10 nm to about 100 nm.

17. The optoelectronic device of claim 11, wherein at least two tubular nanowells are bridged along at least a portion of their lengths by the material forming the nanostructured film.

18. The optoelectronic device of claim 11, wherein the nanostructured film is a metal oxide nanostructured film.

19. The optoelectronic device of claim 11, wherein the nanostructured film is a titanium oxide nanostructured film.

20. A nanostructured film comprising a plurality of tubular nanowells, the tubular nanowells each having a pore at the top surface of the nanostructured film, the pore defining a channel that extends from the top surface of the nanostructured film downwardly towards the bottom surface of the nanostructured film and further wherein, one or more of the tubular nanowells have a tapered end.