Susceptible organic cations enable stable and efficient perovskite solar cells

Abstract

Achieving higher open-circuit voltages and fill factors in perovskite solar cells (PSCs) involves minimizing defects between layers and maximizing carrier extraction and transport. One approach includes integrating a two-dimensional (2D) semiconducting interlayer to form a heterojunction with the perovskite absorber. However, conventional 2D layers often have poor thermal stability due to the migration of organic cations. This study examines the enhancement in power conversion efficiency (PCE) and thermal stability of PSCs by using strong intermolecular interactions between methoxy-phenethylammonium iodide and cyclohexylammonium bromide as chosen organic cations. The resulting 2D/perovskite configuration facilitates efficient charge transfer and demonstrates superior thermal stability at 85 degrees C. The optimized PSCs achieved a PCE of 26.28% under air mass (AM)1.5G illumination, retaining 88% efficiency after 440 h of continuous illumination and maintaining 100% of its initial efficiency after 9,000 h under ambient conditions. This research contributes to developing highly efficient and stable PSCs.