  We introduce a pioneering strategy to enhance the environmental stability of
perovskite thin films, a critical step forward in advancing their application
in optoelectronics. Through the innovative application of matrix encapsulation
techniques, we focus on the stabilization of methylammonium lead iodide
(MAPbI3) and methylammonium lead bromide (MAPbBr3) films. These films are
meticulously prepared via a two-step solution deposition method under
controlled ambient conditions. Our approach involves the application of
poly(methyl methacrylate) (PMMA) and AZ5214 photoresist layers through
spin-coating, aimed at singularly encapsulating the perovskite films. This
encapsulation acts as a robust hydrophobic barrier, significantly mitigating
moisture ingress and simultaneously addressing the challenge of pinhole
presence within the perovskite structure. Through a series of detailed
characterizations-spanning scanning electron microscopy (SEM), X-ray
diffraction (XRD), and photoluminescence (PL) spectroscopy-we demonstrate that,
despite the thicker nature of the AZ5214 photoresist compared to the PMMA
layer, it exhibits markedly enhanced stability. Notably, the integrity and
optical properties of the perovskite films are preserved for extended periods
of up to 960 hours under environmental exposure. This breakthrough highlights
the superior performance of AZ5214 photoresist over PMMA in prolonging the
operational life of perovskite thin films, thereby offering a promising avenue
for their deployment in a wide range of optoelectronic devices.
