Low Temperature Atomic Layer Deposition on Top of Functional Organic Layers and Devices for Organic Electronics
Final Report Abstract
ALD films grown on top of organic layers can cause strong degradation effects because the precursors can penetrate deep into the organic bulk. Metal oxides such as MoO3 are able to protect organics against impinging precursors during an ALD process. Metal oxides are also very efficient hole-injection and -extraction layers because they exhibit very deep lying electronic states. Air exposure can affect the electronic properties of metal oxide because of surface contaminations. However, when transferred under inert conditions or only shortly exposed to air MoO3 remains a very efficient hole-injection layer. Nano-laminates comprised of alternating Al2O3/ ZrO2 sub-layers are very effective gas diffusion barriers. The origin was attributed to three key factors: (i) a higher packing density due to suppressed crystallization. (ii) It was found that ZrO2 efficiently hampers the corrosion of the neat Al2O3 by water, a major source of deterioration of the barrier functionality. (iii) An aluminate phase was identified by XPS at the Al2O3/ ZrO2 sub-layer interfaces which leads to a stabilization and densification of the nano-laminate barrier. The high conductivity of nano-laminates comprised of alternating Al2O3/ ZnO was attributed to a combination of (i) a structural modification of ZnO crystals by Al2O3 and (ii) an Al doping of the ZnO lattice. In addition, it was identified that Al2O3/ ZnO nano-laminates are degenerately doped with a WF of 4 eV, independent of the doping concentration. Finally, it was shown that a structure comprised of an Al2O3/ ZnO nano-laminate/ MoO3/ organic layer can be used as effective charge recombination and charge generation unit in stacked OPVs and OLEDs, respectively.
Publications
- Charge Generation Layers Comprising Transition Metal-Oxide/Organic Interfaces: Electronic Structure and Charge Generation Mechanism. Appl. Phys. Lett. 96, 193302 (2010)
J. Meyer, M. Kröger, S. Hamwi, F. Gnam, T. Riedl, W. Kowalsky, and A. Kahn
- Effect of Contamination on the Electronic Structure and Hole-Injection Properties of MoO3/Organic Semiconductor Interfaces. Appl. Phys. Lett. 96, 133308 (2010)
J. Meyer, A. Shu, M. Kröger, and A. Kahn
- Molecular-scale properties of MoO3-doped pentacene. Phys. Rev. B 82, 155434 (2010)
S. D. Ha, J. Meyer, and A. Kahn
- The Origin of Low Water Vapor Transmission Rates Through Al2O3/ZrO2 Nanolaminate Gas- Diffusion Barriers Grown by Atomic Layer Deposition. Appl. Phys. Lett. 96, 243308 (2010)
J. Meyer, H. Schmidt, W. Kowalsky, T. Riedl and A. Kahn
- The role of transition metal oxides in charge generation layers for stacked organic light emitting diodes. Adv. Funct. Mater. 20, 1762 (2010)
S. Hamwi, J. Meyer, M. Kröger, T. Winkler, M. Witte, T. Riedl, A. Kahn, and W. Kowalsky
- Electronic structure of molybdenum-oxide films and associated charge injection mechanisms in organic devices. J. Photon. Energy, 1, 011109 (2011)
J. Meyer and A. Kahn
- Electronic structure of Vanadium pentoxide: An efficient hole injector for organic electronic materials. J. Appl. Phys. 110, 033710 (2011)
J. Meyer, K. Zilberberg, T. Riedl, and A. Kahn
- Evidence for near-Surface NiOOH Species in Solution-Processed NiOx Selective Interlayer Materials: Impact on Energetics and the Performance of Polymer Bulk Heterojunction Photovoltaics. Chem. Mater. 23, 4988–5000 (2011)
E. L. Ratcliff, J. Meyer, K. X. Steirer, A. Garcia, J. J. Berry, D. S. Ginley, D. C. Olson, A. Kahn, and N. R. Armstrong
- Inverted organic solar cells with sol-gel processed high work-function vanadium oxide holeextraction layers. Adv. Funct. Mater. 21, 4776 (2011)
K. Zilberberg, S. Trost, J. Meyer, A. Kahn, A. Behrendt, D. Lützenkirchen-Hecht, R. Frahm, and T. Riedl
- Low-Temperature Atomic Layer Deposition. In: Atomic Layer Deposition of Nanostructured Materials, N. Pinna and M. Knez (eds.), Wiley- VCH, Weinheim, 109 (2011)
J. Meyer and T. Riedl
- MoO3 Films Spin-coated from Nanoparticle Suspension for Efficient Hole-Injection in Organic Electronics. Adv. Mat. 23, 70 (2011)
J. Meyer, R. Khalandovsky, P. Görrn and A. Kahn
