In perovskite photovoltaic systems, ammonium salts are widely utilized to convert residual PbI₂ and undercoordinated Pb²⁺ species into two-dimensional (2D) perovskite layers, thereby providing surface passivation for the three-dimensional (3D) perovskite absorber. Nevertheless, conventional 2D passivation strategies are hindered by the intrinsic trade-off between passivation efficiency and charge transport, as 2D perovskites typically exhibit suboptimal band alignment and limited electrical conductivity.
To address this limitation, researchers from China's Zhejiang University and ZJU-Hangzhou Global Scientific and Technological Innovation Center have introduced an interfacial n-type modulation approach within 2D perovskite interlayers.
Specifically, the incorporation of SbCl₃ into phenylethylammonium iodide (PEAI)-derived 2D perovskites enables controlled n-type doping, which is subsequently integrated into 3D/2D perovskite heterojunction architectures.
The resulting doped 2D passivation layer facilitates favorable interfacial band alignment, mitigates non-radiative recombination pathways, and preserves intrinsic chemical passivation while simultaneously enhancing electron extraction from the perovskite absorber to the C60 charge transport layer.
This strategy yields inverted perovskite solar cells (PSCs) with a bandgap of 1.68 eV and a maximum power conversion efficiency (PCE) of 23.20%, while tandem perovskite–silicon devices achieve a champion PCE of 33.10% (certified 32.56%) together with improved operational stability.
