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Energy Level Alignment at Metal/Solution‐Processed Organic Semiconductor Interfaces
Author(s) -
Atxabal Ainhoa,
Braun Slawomir,
Arnold Thorsten,
Sun Xiangnan,
Parui Subir,
Liu Xianjie,
Gozalvez Cristian,
Llopis Roger,
MateoAlonso Aurelio,
Casanova Felix,
Ortmann Frank,
Fahlman Mats,
Hueso Luis E.
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201606901
Subject(s) - materials science , photoemission spectroscopy , semiconductor , spectroscopy , organic semiconductor , inverse photoemission spectroscopy , x ray photoelectron spectroscopy , fermi level , kelvin probe force microscope , ultraviolet photoelectron spectroscopy , electron spectroscopy , optoelectronics , chemical physics , electron energy loss spectroscopy , work (physics) , energy dispersive x ray spectroscopy , electron , nanotechnology , chemical engineering , chemistry , scanning electron microscope , composite material , physics , quantum mechanics , engineering , atomic force microscopy , thermodynamics , transmission electron microscopy
Energy barriers between the metal Fermi energy and the molecular levels of organic semiconductor devoted to charge transport play a fundamental role in the performance of organic electronic devices. Typically, techniques such as electron photoemission spectroscopy, Kelvin probe measurements, and in‐device hot‐electron spectroscopy have been applied to study these interfacial energy barriers. However, so far there has not been any direct method available for the determination of energy barriers at metal interfaces with n‐type polymeric semiconductors. This study measures and compares metal/solution‐processed electron‐transporting polymer interface energy barriers by in‐device hot‐electron spectroscopy and ultraviolet photoemission spectroscopy. It not only demonstrates in‐device hot‐electron spectroscopy as a direct and reliable technique for these studies but also brings it closer to technological applications by working ex situ under ambient conditions. Moreover, this study determines that the contamination layer coming from air exposure does not play any significant role on the energy barrier alignment for charge transport. The theoretical model developed for this work confirms all the experimental observations.