The invention provides an antireflection and self-cleaning thin film and a preparation method thereof. According to the preparation method, a
solid figure structure of a
micron size is processed on a transparent flexible thin film through adopting imprinting technologies and
surface modification technologies, so that the transparent flexible thin film has antireflection and self-cleaning performance; the antireflection and self-cleaning thin film is integrated on the window layer of a
solar battery assembly, and as a result, the
surface reflection of the window layer can be effectively inhibited, and the number of photons entering the
absorption layer of a battery can be increased; and therefore, the
photoelectric conversion efficiency of the battery can be improved, and especially, the efficiency of the battery can be improved more significantly when
sunlight obliquely enters the battery. A super hydrophobic film or a super hydrophilic film can be selected as the antireflection and self-cleaning thin film of the invention; since the super hydrophobic film has a high
water contact angle, when the super hydrophobic film tilts, water droplets are very easy to roll down and take away surface pollutants, and therefore, a self-cleaning effect can be realized; and based on the
photocatalysis, the super hydrophilic film can degrade surface organic contaminations, and therefore, a self-cleaning effect can be also realized.