In situ post-synthesis of luminescent Lewis acid–base adducts

Abstract

Inkjet printing has drawn widespread attention and is considered as one of the most promising technologies for mass manufacturing of optoelectronic devices. Herein, we elaborate a novel strategy to modulate the morphologies of inkjet-printed thin films by optimizing the ink formulation and suppressing the coffee-ring effect, combining the approach of in situ post-synthesis based on Lewis acid–base interactions. Luminescent Lewis acid–base adducts are created immediately during inkjet printing, i.e., in situ post-synthesis based on coordination chemistry. The electron-deficient aryl borane was employed as Lewis acid to trigger the coordination interaction with a Lewis base of a nitrogen-containing fluorescent material, which resulted in the rearrangement of the frontier molecular orbitals. Most likely, a reduced singlet–triplet energy gap and charge transfer would be detectable if the Lewis base is a conjugated fluorophore. This exemplifies the great potential of In situ post-synthesis strategy in the design of new luminescent materials for light-emitting diodes and encryption via inkjet printing.