Soft supermolecule stabilized buried interface for high-performance inverted perovskite solar cells and modules

Self-assembled molecules (SAMs) have emerged as a promising hole transport material for improving the power conversion efficiency (PCE) of p-i-n inverted perovskite solar cells (PSCs). However, molecular aggregation and insufficient coverage of SAMs, the defects at the bottom surface of perovskite films, and weak adhesive force of perovskite films on SAMs result in poor quality and longevity of the interface between SAMs and perovskite (buried interface), hampering the realization of long-term operationally stable inverted PSCs. Here we report a supramolecular host-guest interaction strategy to stabilize buried interface in inverted PSCs. Through incorporating sulfonyl-functionalized calixarene molecules, namely 4-tert-Butylsulfonylcalix[4]arene (SC4A) with soft Lewis basicity, the reinforced buried interface durability is fulfilled by homogenizing SAM film, passivating interface defects, releasing interface residual stress, and bilateral chemical bridging. The resulting inverted PSCs and large-area modules accomplish a certified PCE of 27.12% and 22.25% (aperture area 655.2 cm2), respectively. Moreover, the SC4A-modulated devices retain 97.4% of its initial PCE after continuous operation under one sun illumination for 2125 h, and 90.7% of its original PCE after damp heat aging (85 °C and 85% relative humidity) for 2000 h. Self-assembled interlayers can improve efficiency in inverted perovskite solar cells, but poor coverage and weak interfaces limit stability. Yang et al stabilized the buried interface using supramolecular host–guest chemistry with functionalized calixarene molecules, improving cell’s performance.