Bidimensional SnSe2—Mesoporous Ordered Titania Heterostructures for Photocatalytically Activated Anti-Fingerprint Optically Transparent Layers

The design of functional coatings for touchscreens and haptic interfaces is of paramount
importance for smartphones, tablets, and computers. Among the functional properties, the ability
to suppress or eliminate fingerprints from specific surfaces is one of the most critical. We produced
photoactivated anti-fingerprint coatings by embedding 2D-SnSe2 nanoflakes in ordered mesoporous
titania thin films. The SnSe2 nanostructures were produced by solvent-assisted sonication employing
1-Methyl-2-pyrrolidinone. The combination of SnSe2 and nanocrystalline anatase titania enables
the formation of photoactivated heterostructures with an enhanced ability to remove fingerprints
from their surface. These results were achieved through careful design of the heterostructure and
controlled processing of the films by liquid phase deposition. The self-assembly process is unaffected
by the addition of SnSe2, and the titania mesoporous films keep their three-dimensional pore organization.
The coating layers show high optical transparency and a homogeneous distribution of
SnSe2 within the matrix. An evaluation of photocatalytic activity was performed by observing the
degradation of stearic acid and Rhodamine B layers deposited on the photoactive films as a function
of radiation exposure time. FTIR and UV-Vis spectroscopies were used for the photodegradation
tests. Additionally, infrared imaging was employed to assess the anti-fingerprinting property. The
photodegradation process, following pseudo-first-order kinetics, shows a tremendous improvement
over bare mesoporous titania films. Furthermore, exposure of the films to sunlight and UV light
completely removes the fingerprints, opening the route to several self-cleaning applications.