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FAST RESPONSE ELECTROCHROMIC DEVICE ON POLYMERIC SUBSTRATE( F.R.E.D.O.P.S. )

Objective

New optical composite materials are needed to obtain a dynamic control of light and energetic transmission properties of glazed systems. Electro-Chronism (EC) is a promising technique to obtain variable transmittance, or different colours, by electric voltage switching. Nevertheless several open problems still remain in this technology, namely in the lifetime and reliability aspects.

Specific goal of the project is to develop a Fast Response EC Device On Polymeric Substrate (FREDOPS), opening a new R & D path respect to the more diffuse line, based on coatings on glass substrates.
A dynamic control of light and energy transmission properties of glazed systems can be obtained by Electro-Chromic (EC) devices, that modify their optical properties according to the value of the electric voltage applied to the two external electrically conducting layers. The development of EC devices is a world-wide challenge, focused to the solution of reliability and durability aspects, necessary condition for an industrial exploitation.

Glass has been the standard substrate for the EC device development, as it is the most widely used transparent material. On the contrary, the FREDOPS project is addressed to the development of a fast response EC device on a polymeric substrate.

FREDOPS can be widely applied: from building or transport glazing systems to communication displays, light control systems for visual protection (visors, spectacles, etc...) architectural applications, etc...

Several alternative materials have been explored and tested for each different layer type. The synthetical description of the finally proposed device is:
PET-ITO/WO3/'cl'BPEI-1.5 H3PO4/polymeric fluorindine/ITO-PET

Test results have shown very good typical performance values for exchanged charge (2-3 mC/cm{2}), optical density variation (0.4-0.5) and coloration efficiency (average value 145 cm{2}/C). Typical transmittance variations are from 60% in bleached state to 15% in colored state (contrast ratio 4:1). Time responses had to be kept slow (60 s coloring, 150 s bleaching) in order not to degrade performance with long term (10{4}) cycling. Temperature operating range is between 5 and 45 C. Storage temperatures are between -20 and 60 C. No UV damage occurs.

The possibility of producing 200 x 160 mm{2} samples has been demonstrated: further efforts are necessary if an industrial product development phase is started.

Important results have been obtained on the technologies for producing new materials for EC devices on polymeric substrate. The best performing ITO transparent coating on polymeric films has been produced, a new temperature stable polymeric electrolyte developed, an new organic electrochromic dye patented, a tungsten trioxide coating on polymeric film, as good as those ones obtained on glass, produced in 250 x 300 mm size, a technique for lamination of EC films based on PET between glasses developed and tested, an innovative characterisation technique (photoelectrochemistry) applied for the first time to electrochromic layers.
FREDOPS could be widely applicable : from building or transport glazing systems to communication display, light control systems for visual protection (visors, spectacles, etc.), architectural applications, etc. In order to satisfy the required range of specifications, in term of fast response (from 1 to 10 seconds), long term reliability (10 6 cycles, 5 to 10 years lifetime), high contrast level (at least 1 to 5) max operating temperature (from 70 to 110 degreesC) three different basic system have been lected as candidates for FREDOPS.

The obtained FREDOPS systems will be submitted to an extensive performance and durability test frequence.

The most promising solutions will be selected.

2

Coordinator

Conphoebus Istituto di Ricerche per le Energie Rinnovabili e il Risparmio Energetico Scrl
Address
Zona Industriale
95030 Piano D'arci Catania
Italy

Participants (6)

Centre Scientifique et Technique du Bâtiment (CSTB)
France
Address
Établissement De Grenoble
38000 Grenoble
HYDROMÉCANIQUE ET FROTTEMENT R&D SA
France
Address
Zone Industrielle Sud, Rue Benoit Fourneyron
42166 Andrezieux-boutheon
INSTITUT NATIONAL POLYTECHNIQUE DE GRENOBLE
France
Address
Rue De La Piscine, 1130 - Domaine Universitaire De
38402 Saint-martin-d'heres
Innovative Sputtering Technology NV
Belgium
Address
Karreweg 18
9870 Zulte
NKT Research Center a/s
Denmark
Address
Sognevej 11
2605 Broendby
Società Italiana Vetro SpA
Italy
Address
Zona Industriale
66050 San Salvo