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

In this study, we investigated the multi-jet mode modified electrospray deposition (ESD) production of NPB/Alq(3) small-molecule multilayer structures with suppressed interface mixing, using common solvents. Observations of the initial deposition stage and analysis of the photoluminescence spectra of the multilayer structure were conducted. It was demonstrated that, by optimizing the deposition conditions, surface erosion of the NPB layer and the initiation of interface mixing between the NPB and Alq(3) layers could be suppressed. A 55-nm NPB/60-nm Alq(3) multilayer structure with suppressed intermixing and smooth surface morphology (RMS roughness of 3.9nm) was obtained at the lowest levels of under-layer erosion. Schematic of a modified electrospray (nanomist deposition: NMD) system and an NPB/Alq(3) multilayer structure deposited by NMD.