Synergistic Engineering of Pre‐Seed and Cross‐Interface Heterojunctions for Advanced Printable Carbon‐Based Perovskite Solar Cells

In printable carbon‐based perovskite solar cells (p‐MPSCs) utilizing a mesoporous TiO 2 /ZrO 2 /carbon architecture optimized for large‐scale fabrication, power conversion efficiency (PCE) is limited by suboptimal perovskite crystallization due to drop‐casting and the absence of a hole‐transporting layer, both of which hinder efficient charge transport and extraction. Herein, an innovative dual strategy combining seed‐induced crystallization and interface energy level engineering is introduced to enhance p‐MPSC performance. Specifically, CsPbBr 3 seeds embedded within the mesoscopic TiO 2 electron transport layer promote large‐grain perovskite growth, while a screen‐printed SnS quantum dot (QD) layer on mesoporous ZrO 2 forms a type‐II SnS QD/perovskite heterojunction. This approach effectively suppresses grain boundary recombination and optimizes band alignment, reducing energy barriers and enhancing carrier dynamics at the perovskite/carbon interface. The resulting p‐MPSC achieves an impressive PCE of 20.8% and an open‐circuit voltage ( V OC ) of 1.067 V, the highest V OC reported for organic–inorganic hybrid p‐MPSCs to date. Additionally, a large‐area module (17.88 cm 2 ) delivers a remarkable PCE of 17.1% with excellent long‐term operational stability. This work presents a robust strategy for simultaneously optimizing crystallization and hole extraction, paving the way for high‐efficiency, scalable p‐MPSCs.