Organic Semiconductor/Gold Interface Interactions: From Physisorption on Planar Surfaces to Chemical Reactions with Metal Nanoparticles

Abstract

The interaction of gold nanoparticles (AuNPs) with prototypical organic semiconductors used in optoelectronics, namely, tris(8-hydroxyquinoline)aluminium (Alq3 ) and 4,4-bis[N-(1-naphthyl)-N-phenylamino]diphenyl (α-NPD), is investigated in situ by X-ray photoelectron spectroscopy (XPS). These AuNPs-on-molecule experiments are compared with the reversed molecule-on-Au cases. The molecules-on-Au systems show only weak interactions, and the evolution of the XP spectra is dominated by final-state effects. In contrast, in the AuNPs-on-molecules cases, both initial-state effects and final-state effects occur. Spectral features arising for both molecules and metal indicate charge transfer and the formation of organometallic complexes (initial-state effects). The energy shift in the metal emission underlines the size-induced nanometric nature of the molecule/Au interaction (final-state effects). Consequently, the chemical interaction between metals and organic semiconductors likely depends strongly on the deposition sequence in general.

On the Nature of Charge-Injecting Contacts in Organic Field-Effect Transistors

“…In this context, it is worth mentioning that the deposition of Au electrodes on perylenes similar to P13 has been demonstrated to form Au nanoclusters on the OSC layer, on which a physisorption process has been proven to occur. 25 However, considering that even noble metals could show chemical reactivity at the nanoscale level, 45 the different chemical structure of the two OSCs could play a major role in determining the nature of interaction with the nanostructured electrode.…”

Improving Charge Injection at Gold/Conjugated Polymer Contacts by Polymer Insulator‐Assisted Annealing for Transistors

“…XPS Au 4f core level peaks of DPP-DTT/Au and DPP-DTT@PS/Au films also shift to higher binding energy after annealing (Figure S16, Supporting Information), which might result from the change of the microstructures of gold atoms packing and the charge transfer between gold and conjugated polymer. [63,65] For example, the gold nanoparticles in the annealing process will diffuse, and thus agglomerate. [70] The UPS results show that the surface electronic structures of DPP-DTT/Au and DPP-DTT@PS/Au films also change significantly after annealing (Figure S17, Supporting Information).…”

“…[57,60,61] Metals and organics may have some interactions, forming physisorption or even chemical bonds, depending on the properties of metal and organics. [62][63][64][65] Chemical reaction could occur between gold and S atoms, and the physical and chemical properties of this interface could be modified. [63][64][65][66][67][68] The interaction between the polymer film and the deposited gold is detected by XPS.…”

“…[62][63][64][65] Chemical reaction could occur between gold and S atoms, and the physical and chemical properties of this interface could be modified. [63][64][65][66][67][68] The interaction between the polymer film and the deposited gold is detected by XPS. Figure 5e shows the XPS S 2p spectra of DPP-DTT film.…”

Plasmonic Metasurfaces as Surface-Enhanced Infrared Absorption Substrates for Optoelectronics: Alq3 Thin-Film Study

“…21 FTIR and Raman spectroscopy were implemented to study the degradation of geometric isomers over time and after the annealing of the films. 22 Alq 3 molecules are a favorable choice for SEIRA spectroscopy since they are physisorbed on the gold surface, 23 and classical electromagnetic models could be used for the explanation of the near-field enhancement effect. Nevertheless, the SEIRA vibrational analysis of Alq 3 has not been reported yet, though it is a promising tool for improving the performance of organic devices.…”