Dehydration-Reaction-Based Low-Temperature Synthesis of Amorphous SnO_x for High-Performance Perovskite Solar Cells

The development of methodologies for synthesizing carrier-transporting materials is critical for optoelectronic device fabrication. Amorphous metal oxides have emerged as potential carrier transport materials for perovskite tandem solar cells and flexible electronics due to their ease of fabrication and excellent electronic properties. However, perovskite solar cells employing amorphous metal oxides as the electron-transporting layers (ETLs) remain inefficient. This research describes a moderate dehydration reaction for the low-temperature synthesis of amorphous SnO_x. We investigated this amorphous SnO_x as the ETL for perovskite solar cells and demonstrated a maximum power conversion efficiency (PCE) of 20.4%, the greatest efficiency ever attained with an amorphous metal oxide ETL produced below 100 °C. Remarkably, the device maintained 85% of its initial efficiency for more than 4800 h. Furthermore, flexible perovskite solar cells based on this amorphous SnO_x have a maximum PCE of 11.7%. Finally, this amorphous SnO_x was used to fabricate LEDs and exhibited a maximum external quantum efficiency of over 3%.