Organic-inorganic hybrid perovskite (OIHP)
solar cells have achieved comparable efficiencies to those of commercial solar
cells, although their instability hinders their commercialization. Although
encapsulation techniques have been developed to protect OIHP solar cells from
external stimuli such as moisture, oxygen, and ultraviolet light, understanding
of the origin of the intrinsic instability of perovskite films is needed to
improve their stability. We show that the OIHP films fabricated by existing
methods are strained and that strain is caused by mismatched thermal expansion
of perovskite films and substrates during the thermal annealing process. The
polycrystalline films have compressive strain in the out-of-plane direction and
in-plane tensile strain. The strain accelerates degradation of perovskite films
under illumination, which can be explained by increased ion migration in
strained OIHP films. This study points out an avenue to enhance the intrinsic
stability of perovskite films and solar cells by reducing residual strain in
perovskite films.
Bibliography.
Jingjing Zhao, Y. D. (17 de Nov de 2017). Strained hybrid
perovskite thin films and their impact on the intrinsic stability of
perovskite solar cells. Materials Science, 3, no 11.
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