Design and Synthesis of Triphenylamine-Based Self-Assembled Monolayers for Energy Level Alignment in Inverted Perovskite Solar Cells

Self-assembled monolayers (SAMs) have emerged as promising interfacial materials for inverted perovskite solar cells owing to their ability to tune surface energetics, improve charge extraction, and promote defect passivation.1,2 Herein, we report the design, synthesis, and characterization of a library of triphenylamine-based SAMs featuring distinct core substituents, linker architectures, and phosphonic acid anchoring groups. Twelve SAM candidates were prepared through Ullmann condensations, Buchwald–Hartwig aminations, Hirao couplings, Vilsmeier–Haack formylations, and Knoevenagel condensations, yielding nine unprecedented compounds. Molecular design was guided by variations in the electronic nature of the triphenylamine core, incorporation of heteroaromatic units, and linker modifications to expand the structural diversity of SAM materials. These compounds provide a versatile platform for investigating structure–property relationships and valuable molecular frameworks for perovskite solar cells and related optoelectronic devices.