Two-dimensional/three-dimensional
(2D/3D) Ruddlesden–Popper
perovskite materials have shown the enormous potential to achieve
both efficient and stable photovoltaic devices for commercial applications.
Unfortunately, the single function of spacer cations limits their
further improvements in efficiency to reach values as high as those
of 3D perovskites. Herein, we developed a new-type multifunctional
heterocyclic-based spacer cation of 2-(methylthio)-4,5-dihydro-1H-imidazole
(MTIm+) to achieve a synchronous improvement of efficiency
and stability for 2D/3D perovskite solar cells (PSCs). Owing to the
presence of special chemical groups (imidazole and methylthio), strong
interactions have been found between MTIm+ and the 3D perovskite
component, leading to an excellent passivation effect. More important,
at the initial stage of crystallization, uniform nucleation distribution
would be generated around the spacer cation, which is helpful for
improved crystallinity and reduced growth defects. The smaller layer
space compared to that of cations based on aromatic hydrocarbons caused
effective carrier transfer between inorganic layers in 2D/3D perovskites.
As a result, the 2D/3D (n = 30) PSCs based on MTIm
exhibit a champion PCE up to 21.25% with a high V
oc of 1.14 V. Besides, the 2D/3D perovskite devices have
realized dramatically enhanced humidity and thermal stability, maintaining
94% of the starting PCE enduring aging at about 50% RH for 2880 h
and at 85 °C for 360 h, respectively. We believe that it would
provide a significant strategy to further promote the photovoltaic
performances and the long-term stability of 2D/3D perovskite devices
toward future practical applications.
Two-dimensional (2D) perovskites, as an important part of organic-inorganic hybrid halide perovskite materials, have attracted more and more attention due to their excellent stability, especially water resistance, and become a...
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