Surface coatings based on polysilsesquioxanes: solution-processible smooth hole-injection layers for optoelectronic applications.

Optoelectronic devices usually consist of a transparent conductive oxide (TCO) as one electrode. Interfacial engineering between the TCO electrode and the overlying organic layers is an important method for tuning device performance. We introduce poly(methylsilsesquioxane)-poly(N,N-di-4-methylphenylamino styrene) (PMSSQ-PTPA) as a potential hole-injection layer forming material. Spin-coating and thermally induced crosslinking resulted in an effective planarization of the anode interface. HOMO level (-5.6 eV) and hole mobility (1 × 10(-6)  cm(2)  · Vs(-1) ) of the film on ITO substrates were measured by cyclovoltammetry and time-of-flight measurement demonstrating the hole injection capability of the layer. Adhesion and stability for further multilayer built-up could be demonstrated. Contact angle measurements and tape tests after several solvent treatments proved the outstanding film stability.

[1]  R. Zentel,et al.  Tailored Semiconducting Polymers: Living Radical Polymerization and NLO-Functionalization of Triphenylamines , 2002 .

[2]  Fei Huang,et al.  Thermally Cross-Linkable Hole-Transporting Materials for Improving Hole Injection in Multilayer Blue-Emitting Phosphorescent Polymer Light-Emitting Diodes , 2008 .

[3]  Nasser N Peyghambarian,et al.  Covalently Interlinked Organic LED Transport Layers via Spin-Coating/Siloxane Condensation , 1999 .

[4]  Rigoberto C. Advincula,et al.  Grafting Hole-Transport Precursor Polymer Brushes on ITO Electrodes : Surface-Initiated Polymerization and Conjugated Polymer Network Formation of PVK , 2008 .

[5]  Niyazi Serdar Sariciftci,et al.  Organic solar cells: An overview , 2004 .

[6]  Xiabin Jing,et al.  Novel hole-transporting materials based on 1,4-bis(carbazolyl)benzene for organic light-emitting devices , 2004 .

[7]  Alex K.-Y. Jen,et al.  Thermally crosslinked hole-transporting layers for cascade hole-injection and effective electron-blocking/exciton-confinement in phosphorescent polymer light-emitting diodes , 2006 .

[8]  Fei Huang,et al.  Thermally Cross-Linkable Hole-Transporting Materials on Conducting Polymer: Synthesis, Characterization, and Applications for Polymer Light-Emitting Devices , 2008 .

[9]  Yu-Cheng Lin,et al.  Hole mobilities of thermally polymerized triaryldiamine derivatives and their application as hole-transport materials in organic light-emitting diodes (OLEDs) , 2009 .

[10]  P. Dutta,et al.  Anode Interfacial Engineering Approaches to Enhancing Anode/Hole Transport Layer Interfacial Stability and Charge Injection Efficiency in Organic Light-Emitting Diodes , 2002 .

[11]  M. Schadt,et al.  Voltage-Dependent Optical Activity of a Twisted Nematic Liquid Crystal , 1971 .

[12]  Tobin J Marks,et al.  Molecularly "engineered" anode adsorbates for probing OLED interfacial structure-charge injection/luminance relationships: large, structure-dependent effects. , 2003, Journal of the American Chemical Society.

[13]  Daniel Moses,et al.  High-performance polymer light-emitting diodes fabricated with a polymer hole injection layer , 2003 .

[14]  N. Peyghambarian,et al.  High-efficiency organic electrophophorescent devices through balance of charge injection , 2002 .

[15]  Kok Wai Wong,et al.  CHARACTERIZATION OF TREATED INDIUM-TIN-OXIDE SURFACES USED IN ELECTROLUMINESCENT DEVICES , 1999 .

[16]  A. Jen,et al.  Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer. , 2006, Nano letters.

[17]  A. Jen,et al.  Triarylamine-Containing Poly(perfluorocyclobutane) as Hole-Transporting Material for Polymer Light-Emitting Diodes , 2000 .

[18]  D. Milliron,et al.  Surface oxidation activates indium tin oxide for hole injection , 2000 .

[19]  Walter J. Doherty,et al.  Voltammetric and waveguide spectroelectrochemical characterization of ultrathin poly(aniline)/poly(acrylic acid) films self-assembled on indium-tin oxide. , 2005, Talanta.

[20]  Tobin J. Marks,et al.  Indium Tin Oxide Alternatives—High Work Function Transparent Conducting Oxides as Anodes for Organic Light‐Emitting Diodes , 2001 .

[21]  A. Jen,et al.  Self‐assembled Electroactive Phosphonic Acids on ITO: Maximizing Hole‐Injection in Polymer Light‐Emitting Diodes , 2008 .

[22]  P. Dutta,et al.  Covalently bound hole-injecting nanostructures. Systematics of molecular architecture, thickness, saturation, and electron-blocking characteristics on organic light-emitting diode luminance, turn-on voltage, and quantum efficiency. , 2005, Journal of the American Chemical Society.

[23]  Joshua E. Malinsky,et al.  SELF-ASSEMBLY PROCESSES FOR ORGANIC LED ELECTRODE PASSIVATION AND CHARGE INJECTION BALANCE , 1999 .

[24]  P. Théato,et al.  Synthesis of Processable Inorganic-Organic Hybrid Polymers Based on Poly(silsesquioxanes) : Grafting from Polymerization Using ATRP , 2008 .

[25]  T. Klapwijk,et al.  Indium contamination from the indium–tin–oxide electrode in polymer light‐emitting diodes , 1996 .

[26]  C. Tang,et al.  Organic Electroluminescent Diodes , 1987 .

[27]  T. Hayakawa,et al.  Novel Hyperbranched Phthalocyanine as a Hole Injection Nanolayer in Organic Light‐Emitting Diodes , 2007 .

[28]  C. C. Wu,et al.  Surface modification of indium tin oxide by plasma treatment: An effective method to improve the efficiency, brightness, and reliability of organic light emitting devices , 1997 .

[29]  P. Dutta,et al.  Characterization of transparent conducting oxide surfaces using self-assembled electroactive monolayers. , 2008, Langmuir : the ACS journal of surfaces and colloids.

[30]  C. Adachi,et al.  Organometallic complexes as hole-transporting materials in organic light-emitting diodes. , 2004, Inorganic chemistry.

[31]  Hiroshi Kageyama,et al.  Charge carrier transporting molecular materials and their applications in devices. , 2007, Chemical reviews.

[32]  Sankaran Thayumanavan,et al.  Synthesis of Unsymmetrical Triarylamines for Photonic Applications via One-Pot Palladium-Catalyzed Aminations , 1997 .

[33]  P. C. Chui,et al.  Improved performance of OLEDs with ITO surface treatments , 2005 .

[34]  Mark E. Thompson,et al.  New Thermally Cross-Linkable Polymer and Its Application as a Hole-Transporting Layer for Solution Processed Multilayer Organic Light Emitting Diodes , 2007 .

[35]  Joseph Shinar,et al.  Effects of aquaregia treatment of indium-tin-oxide substrates on the behavior of double layered organic light-emitting diodes , 1997 .

[36]  Alan J. Heeger,et al.  Polymer light-emitting diodes with polyethylene dioxythiophene–polystyrene sulfonate as the transparent anode , 1997 .

[37]  T. Marks,et al.  Nanoscale Covalent Self-Assembly Approach to Enhancing Anode/Hole-Transport Layer Interfacial Stability and Charge Injection Efficiency in Organic Light-Emitting Diodes , 2001 .

[38]  P. Théato,et al.  Synthesis of Functional Inorganic-Organic Hybrid Polymers Based on Poly(silsesquioxanes) and Their Thin Film Properties , 2008 .

[39]  Z. You,et al.  Surface properties of treated ITO anodes for organic light-emitting devices , 2005 .

[40]  Wei Huang,et al.  Hole-injection enhancement by copper phthalocyanine (CuPc) in blue polymer light-emitting diodes , 2001 .

[41]  Mark E. Thompson,et al.  Asymmetric Triaryldiamines as Thermally Stable Hole Transporting Layers for Organic Light-Emitting Devices , 1998 .

[42]  Peter Strohriegl,et al.  Charge‐Transporting Molecular Glasses , 2002 .

[43]  Kwanghee Lee,et al.  Synthesis of a new cross-linkable perfluorocyclobutane-based hole-transport material. , 2006, Organic letters.

[44]  Bernard Kippelen,et al.  2,7‐Bis(diarylamino)‐9,9‐dimethylfluorenes as Hole‐Transport Materials for Organic Light‐Emitting Diodes , 2003 .

[45]  Franco Cacialli,et al.  Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes: The relation between the anode physical, chemical, and morphological properties and the device performance , 1998 .