Chlorination strategy facilitates 3D/2D heterojunction formation for high-performance perovskite solar cells

Abstract The introduction of 4-Chlorobenzamidine Hydrochloride (4Cl-BA) salt on the surface of a three-dimensional (3D) perovskite successfully resulted in the formation of a 2D/3D heterojunction architecture in the perovskite solar cells (PSCs). The XRD patterns and SEM images confirm the formation of 2D perovskite on the surface of 3D perovskite. The increased PL intensity indicates a reduction in non-radiative recombination. The photovoltaic parameters showed a considerable improvement in the efficiency of 23.18% for the 2D/3D heterojunction modified PSCs, while the control one delivered an efficiency of 21.94%. The EQE spectrum exhibited the promoted capability of carrier collection over the whole wavelength region. This study demonstrated the feasibility of the chlorination strategy in improving the efficiency of perovskite devices by forming a 2D/3D heterojunction.