Forming a low-dimensional (LD) capping layer over the surface of three-dimensional (3D) perovskites is a known approach for stabilizing perovskite solar cells (PSCs). However, the performance of treated PSCs tends to be limited by inefficient charge transfer across the LD/3D interfaces.
Recently, researchers from China's Nanjing University of Aeronautics and Astronautics and University of Macau developed 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, the team 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, these cells maintained over 95% initial efficiency after rigorous 1200 h damp-heat testing at high temperature (85 °C) and high humidity (85%) conditions, which the scientists referred to as "among the most stable 1D/3D PSCs".
