Nanometer-scale dielectric self-assembly process for anode modification in organic light-emitting diodes. Consequences for charge injection and enhanced luminous efficiency

Joshua E. Malinsky, Jonathan G C Veinot, Ghassan E. Jabbour, Sean E. Shaheen, Jeffrey D. Anderson, Paul Lee, Andrew G. Richter, Alexander L. Burin, Mark A Ratner, Tobin J Marks, Neal R. Armstrong, Bernard Kippelen, Pulak Dutta, Nasser Peyghambarian

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Layer-by-layer, self-limiting chemisorptive siloxane self-assembly using Si3O2Cl8 as the precursor affords thin, conformal, relatively dense, largely pinhole-free dielectric films that can be deposited on oxide surfaces with sub-nanometer control of film thickness (8.3(1) Å/layer). Deposition chemistry, microstructure, and hole injection/work function modification properties of these (SiO2)x-like films on single-crystal Si(111) and polycrystalline indium tin oxide (ITO) substrates have been characterized by synchrotron specular X-ray reflectivity, cyclic voltammetry, X-ray and UV photoelectron spectroscopy, and atomic force microscopy. Chemisorption of these (SiO2)x films onto the ITO anodes of three-layer, vapor-deposited organic electroluminescent devices (ITO/(SiO2)x/TPD/Alq/Al) nearly triples the external quantum and luminous efficiencies. The efficiency enhancement is attributed to hole and electron injection fluence balance caused by modification of the effective voltage profile brought about by the assembly of well-ordered siloxane layers. Interestingly, as a function of increasing (SiO2)x layer thickness, device turn-on voltage first increases (x = 0 → 1), progressively decreases (x = 1 → 2 → 3), and then increases (x = 3 → 4). A theoretical model based upon computation at the ab initio level is proposed in which the self-assembled dielectric layers induce an additional, thickness-dependent "built-in" electric field across the organic transport layers, thereby simultaneously enhancing electron injection from the cathode (increasing luminescence efficiency) and decreasing the efficiency of hole injection (changing the turn-on voltage).

Original languageEnglish
Pages (from-to)3054-3065
Number of pages12
JournalChemistry of Materials
Volume14
Issue number7
DOIs
Publication statusPublished - 2002

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Charge injection
Organic light emitting diodes (OLED)
Self assembly
Anodes
Tin oxides
Indium
Siloxanes
Electron injection
Electric potential
Luminescent devices
X rays
Dielectric films
Temperature programmed desorption
Photoelectron spectroscopy
Chemisorption
Ultraviolet spectroscopy
Synchrotrons
Oxides
Cyclic voltammetry
Film thickness

ASJC Scopus subject areas

  • Materials Chemistry
  • Materials Science(all)

Cite this

Nanometer-scale dielectric self-assembly process for anode modification in organic light-emitting diodes. Consequences for charge injection and enhanced luminous efficiency. / Malinsky, Joshua E.; Veinot, Jonathan G C; Jabbour, Ghassan E.; Shaheen, Sean E.; Anderson, Jeffrey D.; Lee, Paul; Richter, Andrew G.; Burin, Alexander L.; Ratner, Mark A; Marks, Tobin J; Armstrong, Neal R.; Kippelen, Bernard; Dutta, Pulak; Peyghambarian, Nasser.

In: Chemistry of Materials, Vol. 14, No. 7, 2002, p. 3054-3065.

Research output: Contribution to journalArticle

Malinsky, JE, Veinot, JGC, Jabbour, GE, Shaheen, SE, Anderson, JD, Lee, P, Richter, AG, Burin, AL, Ratner, MA, Marks, TJ, Armstrong, NR, Kippelen, B, Dutta, P & Peyghambarian, N 2002, 'Nanometer-scale dielectric self-assembly process for anode modification in organic light-emitting diodes. Consequences for charge injection and enhanced luminous efficiency', Chemistry of Materials, vol. 14, no. 7, pp. 3054-3065. https://doi.org/10.1021/cm020293q
Malinsky, Joshua E. ; Veinot, Jonathan G C ; Jabbour, Ghassan E. ; Shaheen, Sean E. ; Anderson, Jeffrey D. ; Lee, Paul ; Richter, Andrew G. ; Burin, Alexander L. ; Ratner, Mark A ; Marks, Tobin J ; Armstrong, Neal R. ; Kippelen, Bernard ; Dutta, Pulak ; Peyghambarian, Nasser. / Nanometer-scale dielectric self-assembly process for anode modification in organic light-emitting diodes. Consequences for charge injection and enhanced luminous efficiency. In: Chemistry of Materials. 2002 ; Vol. 14, No. 7. pp. 3054-3065.
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