Home > Press > Nanomaterials: Formation in a flash - A new lithography technique enables the production of nanoscale patterns of titania for high-tech applications
The nanoscale titania pattern before and after heat-treatment. © 2012 American Chemical Society |
Abstract:
Titanium dioxide, or titania, is an inorganic material commonly used as a whitening agent in food and toothpaste. It is also used as one of the main active ingredients in sunscreens. The properties that make titania useful in commercial applications — namely its whitening ability and high refractive index — are now being exploited in a wide range of technological applications.
One particular area of interest has been the application of titania in dye-sensitized solar cells — devices that can be used to convert sunlight into electricity. Such application often requires the formation of intricate surface patterns, with the key limiting factors for development being cost and speed of processing. Now, Ramakrishnan Ganesan, Mohammad Saifullah and co-workers at the A*STAR Institute of Materials Research and Engineering have described the use of a technique called step-and-flash imprint lithography (SFIL) to produce such patterns on the nanoscale.
"The precursor method to SFIL is thermal nanoimprint lithography, which is extremely time-consuming as it requires temperature-cycling processes to form a pattern," explains Saifullah. "A mold could be pressed into a heated (and softened) resist material or a liquid precursor could be forced into a mold and then hardened upon heating."
Newer processes eliminate the need for heating by using irradiation with ultraviolet (UV) light to harden the polymer. Although this process may be ideal for organic polymer materials, it is more problematic when using inorganic materials such as titania as the liquid precursor materials are highly viscous and do not spread easily. As a result, the dispensing nozzle may sometimes become blocked.
The chemicals used to make titania can also be unstable in solution, so the team had to identify a mixture of components that offered a combination of stability and low viscosity. "We found that an allyl functionalized titanium complex was stable in combination with other polymer precursors," explains Saifullah. The final component of the mixture is a photoinitiator — which starts the polymerization process upon irradiation with UV light.
The mixture was dispensed onto the surface in the form of droplets, and the mold pressed into place to help the liquid spread. Irradiation with UV light results in hardening of the pattern, after which the mold can be removed. A final heating step burns away the organic material, leaving behind a shrunken version of the original pattern made from titania (see image). Significantly, the aspect ratio of the pattern is maintained after the heat-treatment process.
"Our current method is quite specific to titania, but after tackling this most important material, we hope to develop similar procedures for other inorganic materials," says Saifullah.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering
References:
Ganesan, R. et al. Direct patterning of TiO2 using step-and-flash imprint lithography. ACS Nano 6, 1494-1502 (2012). (Direct link to article below)
####
For more information, please click here
Contacts:
A*STAR Research
Copyright © Agency for Science, Technology and Research (A*STAR)
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Agency for Science, Technology and Research (A*STAR):
Institute of Materials Research and Engineering:
Link to original article in ACS Nano:
Related News Press |
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemistry
What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Energy
Development of zinc oxide nanopagoda array photoelectrode: photoelectrochemical water-splitting hydrogen production January 12th, 2024
Shedding light on unique conduction mechanisms in a new type of perovskite oxide November 17th, 2023
Inverted perovskite solar cell breaks 25% efficiency record: Researchers improve cell efficiency using a combination of molecules to address different November 17th, 2023
The efficient perovskite cells with a structured anti-reflective layer – another step towards commercialization on a wider scale October 6th, 2023
Solar/Photovoltaic
Development of zinc oxide nanopagoda array photoelectrode: photoelectrochemical water-splitting hydrogen production January 12th, 2024
Shedding light on unique conduction mechanisms in a new type of perovskite oxide November 17th, 2023
Inverted perovskite solar cell breaks 25% efficiency record: Researchers improve cell efficiency using a combination of molecules to address different November 17th, 2023
Charged “molecular beasts” the basis for new compounds: Researchers at Leipzig University use “aggressive” fragments of molecular ions for chemical synthesis November 3rd, 2023
Printing/Lithography/Inkjet/Inks/Bio-printing/Dyes
Presenting: Ultrasound-based printing of 3D materials—potentially inside the body December 8th, 2023
Simple ballpoint pen can write custom LEDs August 11th, 2023
Disposable electronics on a simple sheet of paper October 7th, 2022
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||