Highly Oriented and Ordered Co-Assembly Monolayers for Inverted Perovskite Solar Cells.

Perovskite solar cells with inverted architecture have remarkable power conversion efficiency (PCE) and operating stability based on self-assembled molecules (SAMs) hole transport layer. Homogeneous distribution and covalent binding mode of SAM monolayers are critical to improving interfacial property and reducing interfacial losses, which can be achieved through molecular design and co-assembly strategy. Here, we propose co-assembly strategy with SAM by employing a novel 2D π-conjugated structure graphdiyne derivative (PAG) with phosphoric acid groups. Through the π-π interaction and hydrogen bonding between PAG and SAM, the enhanced tridentate anchoring and highly ordered molecular orientation perpendicular to the substrate are successfully achieved. The improvement of interfacial characteristics further optimizes the crystalline quality and buried interface properties of perovskite films, allowing us to achieve a remarkable PCE of 26.10 % under standard illumination.