The coating is made from extremely thin clusters of gold, in such small amounts that the added cost would be minimal, sandwiched between thin layers of titanium oxide, which is electrically insulating. The sandwiched materials result in a coating that’s just 10 nanometer thick. For comparison, gold leaf, which is used to adorn furniture and over-priced desserts, is 12 times thicker.
The layer of gold absorbs invisible infrared light from the sun, causing the glass it’s applied to to heat up by up to eight degrees Celsius, preventing moisture in the air from condensing on it. The coating also allows almost all of the visible light from the sun to pass through, leaving the coating invisible to the naked eye.
There is one drawback mentioned in the article, but an additional advantage is also absorbing infra-red rays that would normally pass through a car window and heat it up whilst standing in bright sunshine.
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