Femtosecond laser direct patterning of sensing materials toward flexible integration of micronanosensors

Reported is femtosecond laser direct patterning of sensing materials toward flexible integration of micronanosensors (FIMS), meaning the capability to fabricate multiple functional sensors of smaller size on a nonflat surface of a substrate that is not limited to silicon. As a representative example, a photosensitive SnO(2) colloidal solution (sol) was developed, from which complex micronanostructures were written via a two-photon absorption process. After thermal decomposition of organic components, the patterned SnO(2) microsensors responded to relative humidity (RH) with a variation range of 5 orders of magnitude. FIMS would open a new door for miniaturization of micronanosensors expected in intelligent microsystems.