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

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.