Description

To replace indium tin oxide (ITO) in flexible optoelectronics (OLEDs, photovoltaics), silver nanowire (AgNW) networks represent a viable and promising alternative. However, two major bottlenecks limit their industrialization: their high surface roughness, which causes short-circuits across thin organic active layers, and their chemical instability against atmospheric oxidation. To address these challenges, the ELITE team at XLIM has developed a protective multilayer configuration and surface functionalization techniques to lower both resistance and roughness while improving optical transmittance. On the electronic level, this functionalization drastically decreases the work function of the nanowires, reducing charge injection barriers. In parallel, the generation of hot electrons via the non-radiative damping of surface plasmons on AgNWs is attracting growing interest. To exploit these carriers, the metal/oxide interface must be perfectly controlled. A conventional solution-processed deposition of ZnO nanoparticles produces a porous film rich in electronic trap states that quench the hot carriers. Vacuum-based ion beam-assisted deposition (IBAD) enables the deposition of nanometrically thin, dense oxide layers at room temperature. The assisting ion bombardment densifies the film and modifies its band structure.

 

 

This PhD project aims to achieve a technological leap by combining these approaches within a single flexible OLED architecture. The primary objectives are:


Control the microstructure and energy level alignment of oxides deposited at low temperatures on the XLIM PLATINOM platform, leveraging IBAD-driven densification to optimize hot electron transfer.
Achieve a passivation by combining the grafting of nitrogen-containing molecules with the deposition of dense oxides to quench surface defects (such as oxygen vacancies) and precisely tune the work function.
Map the band alignment in ambient air using PYSA to correlate the physical parameters of the IBAD deposition and organic grafting with the effective work function.