Cavity-Selective Host–Guest Assembly for Modular Buried-Interface Engineering in Perovskite Solar Cells

Buried-interface engineering is critical for inverted perovskite solar cells, yet integrating anchoring, charge transport, electrostatic regulation, and defect passivation within single molecular systems often creates intrinsic trade-offs. Here, we use cavity-selective host–guest recognition to construct a modular, recognition-directed interface. The cavity of dipolar 4-tert-butylsulfonylcalix[4]arene (tBSCA) selectively accommodates the terminal phenyl group of substrate-anchored Ph-4PACz. Comparisons with a structurally related calixarene analogue and competing inclusion orientations identify a thermodynamically preferred Ph-4PACz-tBSCA configuration, distinguishing cavity-selective association from nonspecific interactions. This preferred configuration underpins a preferentially organized dipolar interface that retains Ph-4PACz-mediated anchoring and charge transport while enabling tBSCA to regulate interfacial electrostatics, reduce interfacial defect sites, and suppress defect-assisted halide migration and interfacial accumulation. The resulting devices achieve a PCE of 27.36% (certified at 26.74%), and a 110 cm2 module delivers a certified efficiency of 22.61%. These results demonstrate configuration-selective molecular recognition as a strategy for the modular organization of complementary functions at buried perovskite interfaces.