High-Performance Perovskite Solar Cells Enabled by One-Dimensional Capping Layer with Conjugated Ligands

Forming a low-dimensional (LD) capping layer over the
surface of
three-dimensional (3D) perovskites has been a typical approach for
stabilizing perovskite solar cells (PSCs). However, the performance
of treated PSCs is still limited by inefficient charge transfer across
the LD/3D interfaces. Here, we realized a 1D capping layer over the
perovskite surface via post-treatment with a conjugated quinolinamine
(QA) halide salt. In contrast to 2D perovskites, this unique configuration
enables charge transfer between inorganic slabs and adjacent QA spacers
in the capping layer, resulting in a reduced dielectric confinement
effect and enhanced carrier mobility. In this way, the hole extraction
from bulk perovskite is facilitated while non-radiative recombination
is suppressed at the 1D/3D interface. As a result, we realized 1D/3D
PSCs with a power conversion efficiency of 24.8%, along with negligible
efficiency loss after 3500 h operation under the maximum power point
tracking on 1 Sun illumination. Furthermore, our cells maintained
over 95% initial efficiency after rigorous 1200 h damp-heat testing
at high temperature (85 °C) and high humidity (85%) conditions,
positioning our PSCs among the most stable 1D/3D PSCs.