{"knowledge_schema": {"broad_category": "Chemistry \u2192 Materials Science \u2192 Organic Cations in Perovskite Solar Cells", "refinement": "This topic focuses on the role of organic cations in enhancing the stability and performance of perovskite solar cells, particularly in forming layered structures.", "specific_scope": "The question specifically addresses which organic cation contributes to the formation of a two-dimensional (2D) layered structure when combined with a three-dimensional (3D) lead halide perovskite.", "goal": "Identify the correct organic cation that enhances the stability of lead halide perovskite solar cells."}, "summary": "This question pertains to the field of materials science, specifically the use of organic cations in perovskite solar cells. It asks which organic cation can enhance the stability of lead halide perovskite solar cells by forming a two-dimensional layered structure when combined with a three-dimensional perovskite. The correct answer is Phenylethylammonium, which is known for its role in improving the stability of these solar cells."}