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Content archived on 2024-04-16

Solid state variable transmission windows


Develop and demonstrate the technical feasibility of electro-chromic windows of 30 x 30 cm2 with a transmission range of better than 50 %, a switching time of 30 sec. and a lifetime of 5000 cycles.

Variable transmission windows offer the possibility of regulating the transmission of visible and infrared solar radiation. This is achieved by coating the window with a stack of thin films.

The coatings consist of five transparent layers: two current conducting layers separated by the electro-chromic electrode, electrolyte and storage layer. The operation of the multi-layer is analogous to a battery in that, with a small voltage, ions from the storage layer will pass through the electrolyte to be inserted into the electro-chromic electrode. This will cause a change in the optical properties of the electro-chromic layer. In this way, the window can be switched from transparent to nearly opaque in the visible region, and also from transparent to highly reflective in the near infrared. These mechanisms have very attractive implications in designing energy efficient buildings in both, warm and hot climates.

In this project different electro-chromic materials and solid electrolyte layers will be investigated; in particular the behaviour of sputtered electro-chromic metal oxide coatings undergoing "lithiation" (Pilkington).

The transparent counter electrode will be developed by the University of Salford. The Li-ion conducting polymer electrolyte with an ion conductivity of around 10 kWcm, will be developed and manufactured by INNOVISION A/S.

Thin film deposition techniques for the active electro-chromic electrode, the storage layer as well as techniques for applying the ion conductive solid electrolyte will be developed (Pilkington, University Salford).

Finally, complete windows of 30 x 30 cm2 will be manufactured where the layered solid state device is laminated between two sheets of glass.


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Call for proposal

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Pilkington plc
EU contribution
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Hall Lane Lathom
L40 5UF Ormskirk
United Kingdom

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Participants (2)