Invited Paper TF+EM-MoA9
Hybrid Inorganic-Organic Thin Films by ALD/MLD for Emerging Energy Technologies

Monday, November 7, 2016, 4:20 pm, Room 105A

For hybrid inorganic-organic materials it is in principle possible to realize properties not seen for conventional materials. An elegant, yet industrially feasible way to link the inorganic and organic entities via strong chemical bonds to form coherent multi-layered hybrid materials is to combine the ALD (Atomic Layer Deposition) technique originally developed to deposit high-quality thin films of simple inorganic materials with MLD (Molecular Layer Deposition) cycles based on organic precursors. This enables the atomic/molecular layer-by-layer production of inorganic-organic hybrid thin films through sequential self-limiting gas-surface reactions with high precision for the film thickness and composition.

In this talk I will discuss our recent efforts towards synthesizing new functional materials by the combined ALD/MLD technique.¹ In particular, we have fabricated oxide-organic thin-film superlattices in which the periodically introduced single/thin organic layers between oxide layers are e.g. shown to hinder phonon transport and substantially enhance the thermoelectric properties of (Zn,Al)O^2,3 and (Ti,Nb)O₂⁴ films. Other exciting application areas foreseen for the ALD/MLD hybrid thin films include the flexible and transparent Li-ion microbattery materials^5.6 and so-called metal organic framework (MOF) materials.⁷

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2. T. Tynell, I. Terasaki, H. Yamauchi & M. Karppinen, Thermoelectric characteristics of (Zn,Al)O / hydroquinone superlattices, J. Mater. Chem. A 1, 13619 (2013).

3. T. Tynell, A. Giri, J. Gaskins, P.E. Hopkins, P. Mele, K. Miyazaki & M. Karppinen, Efficiently suppressed thermal conductivity in ZnO thin films via periodic introduction of organic layers, J. Mater. Chem. A2, 12150 (2014).

4. J.-P. Niemelä, A, Giri, P.E. Hopkins & M. Karppinen, Ultra-low thermal conductivity in TiO₂:C superlattices, J. Mater. Chem. A3, 11527 (2015).

5. M. Nisula, Y. Shindo, H. Koga & M. Karppinen, Atomic layer deposition of lithium phosphorous oxynitride, Chem. Mater.27, 6987 (2015).

6. M. Nisula & M. Karppinen, Atomic/molecular layer deposition of lithium terephthalate thin films as high rate capability Li-ion battery anodes, Nano Lett.16, 1276 (2016).

7. E. Ahvenniemi & M. Karppinen, Atomic/molecular layer deposition: a direct gas-phase route to crystalline metal-organic framework thin films, Chem. Commun.52, 1139 (2016).