Real time investigations during sputter deposition for tailoring optical properties of metal-polymer interfaces

Poster presented at the 16th International Conference on Small-Angle Scattering, held on 13-18th September, 2015, Berlin (Germany).Tailoring optoelectronic properties of metal-polymer interfaces using self-assembly of nanoparticles is of crucial importance in organic electronics and organic photovoltaics [1]. In particular, metal sputter deposition on block-co-polymers is one widely used method to fabricate nanostructured metal layers on a large scale exploiting the selective wetting and doping of metals on polystyrene domains [2,3]. In order to obtain full control over the nanostructural evolution at the metal-polymer interface and its impact on optoelectronic properties, we employed a combination of in situ time-resolved microfocus Grazing Incidence Small Angle X-ray Scattering (μGISAXS) with in situ UV/Vis Specular Reflectance Spectroscopy (SRS) during sputter deposition of gold (Au) on thin polystyrene films (PS). We monitored the evolution of the metallic layer morphology according to changes in the key scattering features by geometrical modeling [4] and correlate the nanostructural development to optical properties. The changes of optoelectronic properties induced by metal nanoparticle growth during the sputter deposition process were exemplarily monitored using SRS. The morphological characterization is complemented by X-ray reflectivity and electron microscopy. This enables us to identify the different growth regimes including their specific thresholds and permits better understanding of the growth kinetics of gold clusters and their self-organization into complex nanostructures on polymer substrates. Thus, our findings are of great interest for applications in organic photovoltaics [5] and organic electronics, which benefit from tailored metal-polymer interfaces