Fabrication of Alq3/NPB small-molecule laminated structures with suppressed interface mixing by multi-jet mode electrospray deposition

Realization of wet fabrication process for small-molecule laminated structures are attractive to spread the application field of high performance organic devices due to large area capability and cost effective mass production. In this study, we present Alq
₃
/NPB small-molecule laminated structures with suppressed interface mixing by electrospray deposition (ESD). It was shown that ESD can deposit Alq
₃
solution with small diameter of less than 1 μm with small deviation by use of multi-jet (MJ) mode. The surface roughness RMS of Alq
₃
layer deposited by the MJ-mode ESD was reduced to be 3.3 nm. It was revealed by a surface morphology observation at initial deposition stage and analysis of photoluminescence spectra of laminated structure, the optimization of deposition condition could suppress the surface erosion and interface mixing between Alq
₃
and NPB layers. It was demonstrated that the MJ-mode ESD is a strong candidate of wet fabrication process of small-molecule laminated structures.