Analyze chemisorbed organic/metal interface by combining the two sub-interfaces model and the integer charge transfer model

Ying-Ying Du,Kurash Ibrahim,Jia-Ou Wang,Hong-Nian Li,Hai-Jie Qian,Wen-Jie Li,Rui Wu,De-Qu Lin,Guang-Hua Chen,Long-Xi Wang

doi:10.1063/1.5086171

Abstract

The electronic structure of PC61BM film on clean Ag(100) and Ag(111) surfaces has been measured with photoemission spectroscopy. The interfaces are chemisorption. It is necessary to combine the two sub-interfaces model and the integer charge transfer model for thoroughly understanding the interfacial electronic structure. The electron injection barrier can then be determined without inverse photoemission measurements, and the PC61BM/Ag(111) system is found to be ohmic contact for electron transport. The analysis method should be applicable to many other organic/metal interfaces.

Highlights

Many organic devices comprise chemisorbed organic/metal interfaces that decide the charge injection or extraction
The two sub-interfaces (TSI) model was suggested.5. In this model the organic/metal interface is constituted by two sub-interfaces
In this work we demonstrate our guess and reveal the significance of combining the TSI and integer charge transfer (ICT) models (TSI+ICT method) on the basis of the photoemission spectra of the PC61BM/Ag(100) and PC61BM/Ag(111) systems

Summary

INTRODUCTION

Many organic devices comprise chemisorbed organic/metal interfaces that decide the charge injection or extraction. Some wellestablished models for inorganic semiconductor/metal interfaces, such as the surface state model, the defect model, and the metalinduced gap states model, can help to analyze the organic/metal interfaces. These models cannot reflect the fact that the inter-molecular interaction is very weak as compared with the molecule-metal interaction. In the past decade the integer charge transfer (ICT) model has been demonstrated to be a powerful ELA model for weak interacting (physisorbed) interfaces. This model has been combined with other models to analyze more complicated interfaces.. Scitation.org/journal/adv of the PC61BM/metal interfaces. The two different Ag substrates were used for observing the different ELA regimes, vacuum level alignment and Fermi level pinning, predicted by the ICT model

EXPERIMENTAL DETAILS

PES data and interfacial interaction

Interfacial energy level diagram

CONCLUSIONS