Antisolvent-assisted one-step solution synthesis of defect-less 1D MAPbI3 nanowire networks with improved charge transport dynamics

Abstract

Abstract In this study, both one-dimensional (1D) and three-dimensional (3D) methylammonium lead iodide (MAPbI3) were successfully synthesized from the same starting precursor solution using a one-step in situ spin-coating process assisted by antisolvent washing with different ethereal solvents. Antisolvent washing with diethyl ether (DE) induced isotropic growth, resulting in dense 3D MAPbI3 films. However, washing with dibutyl ether (DB) having complementary properties promoted 1D directional growth to avoid steric hindrance in the DB/perovskite complex. Antisolvent DB having a lower vapor pressure than DE retarded the vaporization of dimethylformamide and facilitated the growth of larger grains with fewer defects through the slow crystallization. It was also found that long-chain induced 1D directional growth creates an internal compressive strain in the 1D NW film, which plays an important role in charge carrier dynamics. To compare the power conversion efficiency (PCE) and charge transport dynamics, planar solar cells based on both 1D and 3D perovskites were fabricated. 1D NW perovskite based devices achieved a longer lifetime and faster carrier transport owing to the limited ion migration in the presence of compressive strain, although the PCE (15.73%) of the 1D NW-based device was lower than that (18.73%) of the 3D bulk-based device due to inevitable pore incorporation. The improved charge carrier dynamics of 1D NW MAPbI3 can offer potential advantages in the development of optoelectronic devices.