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Controlling the growth of silver nanoparticles on thin films of an n-type molecular semiconductor
Author(s)
Girleanu, Maria
Casula, Giulia
Blanck, Christian
Schmutz, Marc
Contal, Christophe
Cosseddu, Piero
Bonfiglio, Analisa
Ersen, Ovidiu
Brinkmann, Martin
Date Issued
June 11, 2015
Type
Article
Abstract
Nucleation and growth of silver nanoparticles were studied on the surface of an n-type organic semiconductor (N,N′-bis(n-octyl)dicyanoperylene-3,4:9,10-bis(dicarboximide) (N1400)) as a function of the deposition rate τ and the substrate temperature Ts. Electron tomography was used to probe the bulk diffusion of Ag in the N1400 layers. No Ag nanoparticles (NPs) are formed in the bulk of N1400 even for high substrate temperatures, Ts = 125 °C, indicating that Ag diffusion in the organic semiconductor is marginal. The NP distribution on the surface of N1400 is essentially determined by the surface roughness of the N1400 films. A transition in the nucleation mode of Ag NPs on N1400 is evidenced as a function of Ts: for Ts ≥ 50 °C, Ag NPs form random patterns, whereas, for Ts ≥ 75 °C, linear arrays of aligned NPs are observed. Such arrays result from step edge decoration of the N1400 terraces. The surface density of Ag NPs is thermally activated, but the activation energy depends on the structure of the N1400 films: the smaller the crystal size of the N1400 grains, the larger the activation energy.
Citation
Journal of Physical Chemistry C, 119(23), 13115-13123, 2015