UV Photoemission Study of Interfaces Related to Organic EL Devices

1997 ◽  
Vol 488 ◽  
Author(s):  
Kiyoshi Sugiyama ◽  
Kazuhiko Seki ◽  
Eisuke Ito ◽  
Yukio Ouchi ◽  
Hisao ISHII
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Electronic Structures ◽  
Organic Molecule ◽  
Negative Charge ◽  
Photoemission Spectroscopy ◽  
Level Shift ◽  
Vacuum Level ◽  
Organic Electroluminescent ◽  
Photoemission Study

AbstractInterfacial electronic structures related to organic electroluminescent (EL) devices were studied by UV photoemission spectroscopy (UPS). The two classes of interfaces studied were: (1) interfaces in a typical multilayer device AI/AIq3TPD/ITO, where Alq3 is tris(8-hydroxyquinolino)- aluminum, TPD is N,N×-diphenyl-NN×-(3-methylphenyl)- 1, 1‘-biphenyl-4,4’-diamine, and ITO is indium tin oxide, and (2) TTN/metals and TCNQ/metals interfaces, where TTN is tetrathianaphthacene and TCNQ is tetracyanoquinodimethane. The UPS studies of the specimen formed by the successive deposition of TPD, Alq3, and Al on ITO revealed interfacial energy diagrams, with the vacuum level shift of - 0.25 eV (downward) and - 0.1 eV (downward) at the TPD / ITO and the Alq3 / TPD interfaces, respectively. The deposition of TTN and TCNQ on metals showed opposite direction of the shift of the vacuum level, with the positive and negative charge at the vacuum side. This can be explained by considering the chargetransfer between the metal and the organic molecule, with these directions being consistent with the electron donating and accepting ability of these molecules.

Energy Level Alignment at Bebq2/PEI/ITO Interfaces Studied by UV Photoemission Spectroscopy

MRS Advances ◽  
2017 ◽  
Vol 2 (42) ◽  
pp. 2261-2266
Author(s):  
Kohei Shimizu ◽  
Hirohiko Fukagawa ◽  
Katsuyuki Morii ◽  
Hiroumi Kinjo ◽  
Tomoya Sato ◽  
...  
Keyword(s):  
Energy Level ◽  
Work Function ◽  
Indium Tin Oxide ◽  
Electron Injection ◽  
Photoemission Spectroscopy ◽  
Level Shift ◽  
Kelvin Probe ◽  
Vacuum Level ◽  
Energy Level Alignment ◽  
Improvement Effect

ABSTRACTA polyethyleneimine (PEI) interlayer has been applied on indium tin oxide (ITO) to improve electron injection in organic devices including inverted organic light-emitting diodes (OLEDs). To understand the improvement effect by PEI insertion, the energy level alignment at bis(10-hydroxybenzo[h]quinolinato)beryllium (Bebq2)/PEI/ITO interfaces was investigated by UV photoemission spectroscopy (UPS). The deposition of a PEI layer was found to reduce the absolute work function of ITO by 1.4 eV. The vacuum level shifts at Bebq2/ITO and Bebq2/PEI interfaces were also determined as 0.3 eV and 0.1 eV in the direction to reduce the electron injection barrier, respectively. Thus the work function reduction by PEI and downward vacuum level shift at the Bebq2/PEI interface can contribute to the improvement effect. Kelvin probe measurement revealed the weak orientation polarization in Bebq2 film with the bottom side positively polarized. This polarization polarity is also advantageous for electron injection in inverted devices.

Influence of the sputtering system's vacuum level on the properties of indium tin oxide films

2006 ◽  
Vol 500 (1-2) ◽  
pp. 203-208 ◽  
Author(s):  
M.G. Zebaze Kana ◽  
E. Centurioni ◽  
D. Iencinella ◽  
C. Summonte
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Oxide Films ◽  
Vacuum Level ◽  
Tin Oxide Films

PHOTOEMISSION STUDY OF THE INTRA-UNIT-CELL COUPLING IN A TRILAYER CUPRATE

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1691-1696 ◽  
Author(s):  
D. L. FENG ◽  
H. EISAKI ◽  
K. M. SHEN ◽  
A. DAMASCELLI ◽  
C. KIM ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Cuprate Superconductors ◽  
Single Layer ◽  
Interlayer Coupling ◽  
Unit Cell ◽  
Photoemission Spectroscopy ◽  
Cell Coupling ◽  
Lineshape Analysis ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Photoemission Study

The electronic structures of the nearly optimally doped single-layer, bilayer and trilayer Bi-based cuprates are investigated by angle-resolved photoemission spectroscopy. A lineshape analysis of data taken for different photon energies indicates that the interlayer coupling within the trilayer is not stronger than its counterpart in the bilayer system. This suggests that the higher T c of the trilayer cuprate superconductors is not due to an enhancement of the coupling strength between the neighboring CuO2 planes within each unit cell.

Interface properties of organic/indium–tin oxide and organic/GeS(001) studied using photoemission spectroscopy

2000 ◽  
Vol 88 (3) ◽  
pp. 1535-1540 ◽  
Author(s):  
H. Peisert ◽  
T. Schwieger ◽  
M. Knupfer ◽  
M. S. Golden ◽  
J. Fink
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Photoemission Spectroscopy ◽  
Interface Properties
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