The progress of organic electronics demands an increased participation of nanotechnology, and it has already been shown that the presence of metallic nanoparticles and/or nanostructured thin films can enhance the device performance. Nevertheless, to gain control over the device final performance, it is crucial to achieve a profound understanding of the nanostructure development and assembly. We investigate the growth kinetics of silver (Ag) on a tris(8-hydroxyquinolinato)aluminum (Alq3) thin film via sputter deposition. The increase of the average electron density of the Ag nanostructured film is observed to follow a sigmoidal shape development as a function of the deposited Ag thickness, as a consequence of dominant island-mediated growth. The nanoclustered film is percolated at around a thickness of 5.0 ± 0.1 nm. At this film thickness the effective film density is about 50%. Moreover, our simulation results indicate that the shape of the nanoclusters changes from truncated spheres to cylinders upon surpassing the percolation threshold.

S.Y. acknowledges the Knut och Alice Wallenberg foundation for the kind financial support. We thank DFG for funding viagrants RO 4638/1 and MU 1487/18. P.M.B. and Y.Y. thank forfinancial support by TUM.solar in the frame of the Bavarian Collaborative Research Project“Solar technologies go Hybrid”(SolTec) and by the GreenTech Initiative (Interface Sciencefor Photovoltaics - ISPV) of the EuroTech Universities.Portions of this research were carried out at the light source PETRA III at DESY, a member of the Helmholtz Association(HGF).

8 pags., 5 figs.

Peer reviewed