A see-through aerogel made from wood could replace air in double-glazed windows and make them as insulating as walls:
Windows with air sandwiched in the gap between plates of glass can be made better insulators by either increasing the number of glass panels, which can affect visual quality, or expanding the width of the air layer — but anything beyond around 1.5 centimetres becomes detrimental to the insulation effect because convection currents circulate more easily.
To address this, Ivan Smalyukh at the University of Colorado Boulder and his colleagues used nanofibres of cellulose to create an aerogel, a solid gel containing pockets of gas, that could function better than air in double glazing.
Almost all insulation, like fiber glass, function by preventing air circulation (and heat convection). The insulator is the air. But there are better insulators than air, argon for example.
https://www.pressglass.com/noble-gases-and-thermal-insulation-in-windows/#:~:text=Air%20has%20a%20thermal%20conductivity,lower%20than%20that%20of%20air.
I don’t know what gas the aerogel used, but generally anything denser than air is an improvement. Argon is good because it is readily available as a by-product of liquid nitrogen and liquid oxygen production.
Argon diffuses out over the years. Looks like this substance might last longer. Will it stay transparent? Will it deteriorate from UV?
If it’s an aerogel, I would expect it to be cloudy. Translucent, but not quite transparent.
That’s fine for skylights and for basement windows.