Low Temperature Low Cost TiO2 Atmosphere Pressure Plasma Process - OPTICLEAN

Coordinating Institution: CRP Gabriel Lippmann
From: 01/03/2010
To: 28/02/2013
Budget: 300,000.00€
Contact(s): Choquet Patrick

Summary

The use of TiO2 thin films is an attractive solution in many fields such as anti-reflective coatings (when combined with SiO2 layers), self-cleaning, sterilization, degradation of organic pollutants in air and water and the production of solar cell panels. It is well known that the anatase phase is suitable for photocatalytic activities and superhydrophilic properties. Its deposition by sol-gel techniques or by CVD and PVD methods was extensively studied for 40 years. However, low
pressures deposition techniques are too expensive and too difficult to implement on production lines for low cost applications and sol-gel processes result in a low adhesion of coatings with the substrate and require a heating post-treatment. Therefore, there is a need for a new approach to deposit this material.

A very promising alternative is to deposit TiO2 thin films at atmospheric pressure. Recent developments in atmospheric-pressure plasma allow depositing homogenous oxide thin films, mainly SiO2 films, with interesting deposition rates. But very few studies have dealt with producing TiO2 thin films. Interesting works using a Dielectric Barrier Discharge process (DBD) in the plane-to-plane electrode configuration or in downstream post discharge configuration were reported with encouraging results. They highlight the possibility to produce anatase TiO2 films by heating the substrate at around 280°C with growth rates of about 20 nm/min in a plane-to-plane geometry. Nevertheless, direct dielectric barrier discharge cannot be easily used for the treatment of 3D surfaces and built-in particles pollution is a major problem for industrial applications.

Therefore, it is interesting to use a low temperature atmospheric pressure plasma device that permits to treat surfaces, with no dependency on substrate shape and that will be less contaminated by built-in particles pollution.

The main objective of this project is to develop a process and equipment (i.e. a full solution) that produces low temperature and low cost TiO2 coatings in the anatase phase, at less than 200 °C with a deposition rate equivalent to 20 nm/min. This equipment will be based on atmospheric plasma devices manufactured by AcXys Technologies with very innovative
progresses related to this specific application.

The final objective will also be to demonstrate the possibility to implement this technology in industry, showing its potentialities to treat large samples (from 0.1 m2 to a few m2) with high reproducibility. The economic impact of this new environmentally friendly and low cost process (no heating, no use of polluting solvents and no vacuum) would certainly favour the decrease the manufacturing cost of anti-reflective coatings, and promote a larger use of photocatalytic TiO2 thin films.

The two partners have already planned an exploitation plan of the results : AcXys Technologies will handle future promotion and sales of a specific TiO2 solution with experimental demonstrations of its efficiency in targeted markets (self-cleaning and opticalapplications) and for the CRP Gabriel Lippmann, an enlargement of its European expertise inthe field of innovative surface developments (more precisely in the field of crystalline phase TiO2 deposition by atmospheric pressure plasma). The CRP-GL will also share this experience with its Luxembourgish industrial partners. Finally, the collaboration between AcXys Technologies and CRP-GL would permit to extend this service to European companies, and to promote these new TiO2-coated surface properties into mass markets such as transportation, building and packaging.