Electrical insulation checking‐out before perovskite infiltration for optimization in carbon‐based multiporous‐layered‐electrode perovskite solar cells

Abstract Carbon‐based multiporous‐layered‐electrode perovskite solar cells (MPLE‐PSCs) offer excellent stability and low‐cost, fully printable fabrication, but device performance is often limited by electrical leakage between electrodes. Here, we demonstrate that the electrical insulation of MPLE structures, measured as resistance (Ω) before perovskite infiltration, strongly predicts final device performance. Statistical analysis of over 300 devices shows that high‐insulation cells (10 5 –10 7 Ω) consistently achieve high J SC , V OC , fill factor, and power conversion efficiency, whereas low‐insulation cells suffer from severe leakage. We identify the mesoporous ZrO 2 spacer layer as the dominant source of insulation and show that its thickness and thermal treatment are critical. Drying the ZrO 2 layer at 200 °C preserves the porous structure and enables uniform carbon printing, while pre‐sintering at 500 °C causes mechanical damage and degrades insulation. This simple pre‐infiltration insulation screening provides a practical route to improve yield and scalability of carbon‐based perovskite solar cells.