Hydrazinium cation mixed FAPbI3-based perovskite with 1D/3D hybrid dimension structure for efficient and stable solar cells

FAPbI 3 has been greatly developed in Perovskite solar cells (PSCs) profiting from their narrow bandgap, high panchromatic absorption and long carrier diffusion length. Unfortunately, the phase instability of FAPbI 3 -based perovskite restricts its further development in PSCs. Here, hydrazinium cation (HA + : NH 2 NH 3 + ) is incorporated into FAPbI 3 -based perovskite to obtain novel 1D/3D hybrid dimension structure with stable α -FAPbI 3 for the first time. The strong hydrogen bonding of HA + increases the crystallinity and grain size of perovskite. Furthermore, SEM and TEM reveal that the new HA based 1D-phase (1D-HA-phase) exists like “rivet” passivating among the grain boundary of 3D perovskite, forming 1D/3D hybrid dimension structure contributing to the stability of FAPbI 3 -based perovskite. Confocal fluorescence microscopy, time-resolved photoluminescence spectroscopy and Kelvin probe force microscope measurements reveal that the trap state can be effectively restrained and the non-radiative recombination is largely suppressed in HA + mixed FAPbI 3 -based perovskite film with 1D-HA-phase. Finally, stable α -FAPbI 3 -based perovskite and its film with high crystallinity, smooth surface morphology, excellent photovoltaic performance and few defects are obtained. PSC using (FAMACs) 0.85 HA 0.15 perovskite achieves a power conversion efficiency of 21.20% which can retain 90% at room temperature in ambient environment for 2520 h.