A series of CH3NH3PbBr3 (MAPbBr3) nanostructure-based
films with various thicknesses on indium-tin-oxide
(ITO)-covered substrates were fabricated by the spin-coating technique.
The effects of ITO on the structure, surface morphology, and optical
properties of MAPbBr3 thin films were investigated, respectively.
Compared with monolayer MAPbBr3 thin films, the ITO buffer
layer has the effect of improving the crystalline quality and preferential
orientation of MAPbBr3 thin films, realizing the transition
from reverse saturation absorption to saturation absorption. The tunability
of nonlinear optical absorption was achieved by changing the thickness
of the MAPbBr3 film. The maximum three-photon absorption
coefficient of the monolayer MAPbBr3 film was 7.35 ×
10–14 cm3/W2. The maximum
third-order nonlinearity coefficient of MAPbBr3/ITO composite
film was −1.04 × 10–5 cm/W. In addition,
the finite-difference time-domain simulation results were in good
agreement with the experimental results. These results indicate that
the synthesized MAPbBr3 nanostructure-based films have
potential applications in nonlinear optical devices.