Highly Selective Non‐Covalent On‐Chip Functionalization of Layered Materials

Non-covalent functionalization of layered 2D materials is an essential tool to modify and fully harness their optical, electrical, and chemical properties. Herein, a facile method enabling the selective formation of self-assembled monolayers (SAMs) of perylene bisimide (PBI) on transition metal dichalcogenides (TMDs), directly on the growth substrate (on-chip), is presented. Laterally-resolved infrared atomic force microscopy (AFM-IR) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) are applied as superior techniques to gain detailed information beyond traditional surface analysis techniques, such as Raman spectroscopy and AFM, on TMD/PBI structures. The highly selective functionalization conducted in organic solution on MoS2 and WSe2 opens up a pathway to controllable, versatile functionalization of layered materials, which is highly sought after for its potential in passivation, tuning of properties and applications in optics, electronics, and (bio-) sensing.