Preparation of silica thin film by hot pressing process for passive radiative cooling

Thin films have been widely used, and their preparation methods are varied. In this paper, a new type of hot pressing process is introduced to fabricate silicon dioxide thin films based on PET. The thickness of the prepared silica film is up to 40 microns, and the film is transparent. The SiO₂ thin films were deposited uniformly on Polyethylene terephthalate (PET) without obvious cracks, and the films could also be crimped. The prepared silicon dioxide films have the ability of passive radiative cooling, that is, the temperature of the films can reduce to lower than that of the ambient air. It can be expected that this method is also suitable for the preparation of other thin films.