In organic electronic devices, the interfacial dipole at organic/metal interfaces is critical in determining the carrier injection or extraction that limits the performance of the device. A novel technique to enable the direct measurement of underburied dipoles is developed and demonstrated. By tilting the shadow mask by a small angle, metal atoms diffuse into the opening slit to form an ultrathin metal layer during the evaporation process. As the ultrathin metal layer cannot screen out the dipole-induced surface work function change, the dipole strength and direction at the organic/metal interface can be revealed. It was found that the polarity of the organic material, the Fermi-level pinning and the interface morphology all play important roles in dipole formation. By comparing the energy level shifts at the organic/pre-deposited metal and organic/post-deposited metal interfaces, the dipole formed by molecular interactions could be distinguished from the dipole formed by Fermi-level pinning.

Gadolinia-doped ceria (GDC) is a promising electrolyte material for low-temperature solid oxide fuel cells (LT-SOFCs). Many works used ceramic sintering methods to prepare the GDC electrolyte, which was mature and reliable but presented difficulties in rapidly preparing a large area of GDC electrolyte without cracks. The low-pressure plasma spray (LPPS) process has the potential to solve this problem, but few studies have been conducted to date. In this work, submicron GDC powder was agglomerated by a spray drying method to achieve the proper granularity with D₅₀ about 10 μm, and then two dense GDC coatings were fabricated with this agglomerated GDC powder using very-low-pressure plasma spray (VLPPS) and plasma spray–physical vapor deposition (PS-PVD), respectively. The results indicate that the two GDC coatings exhibited similar microstructure but with different densification mechanisms. The VLPPS coating was mainly built up in the form of liquid splats, which had lower mechanical properties due to the lower density and crystallinity, while the PS-PVD coating was co-deposited with the vapor clusters and liquid splats, which had higher density, crystallinity, and mechanical properties. It can therefore be concluded that the GDC coating prepared by PS-PVD is more appropriate for the LT-SOFC application.