The invention discloses a double-selectivity all-inorganic
radiation refrigeration film and a preparation method thereof.The film comprises an adhesion layer, a
metal reflection layer and a multi-layer
dielectric film layer, the adhesion layer is arranged on a bottom layer, the
metal reflection layer is arranged on the upper surface of the adhesion layer, and the multi-layer
dielectric film layer is arranged on the upper surface of the
metal reflection layer; the multi-layer
dielectric film layer comprises a quasi-periodic multi-layer
film structure which is formed by two materials of which the
refractive index difference is greater than a preset threshold value according to a preset thickness in a preset arrangement mode; wherein the number of
layers, the preset arrangement mode and the preset thickness of the multiple dielectric film
layers are obtained by optimizing an ideal spectrum selectively emitted by the double atmospheric transmission windows as an optimization target. The
radiation refrigeration film has the characteristic of high reflection in the solar spectrum range, and can selectively emit
infrared rays at the first atmospheric window and the second atmospheric window at the same time, so that the
radiation refrigeration film has higher refrigeration potential than an existing radiation refrigeration emitter.