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Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
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Low-Temperature Molecular Layer Deposition Using Monofunctional Aromatic Precursors and Ozone-Based Ring-Opening
Laura Svärd1, Matti Putkonen1, Eija Kenttä1
1VTT Technical Research Centre of Finland , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 26, 2017
Summary
This study introduces a new method for organic molecular layer deposition (MLD) using monofunctional precursors and ozone. This approach enables sustained sequential growth of thin films at lower temperatures, overcoming precursor volatility challenges.
Area of Science:
- Materials Science
- Chemical Engineering
- Nanotechnology
Background:
- Molecular Layer Deposition (MLD) is crucial for organic and hybrid coatings.
- Low temperatures required for organic MLD limit precursor volatility.
- Monofunctional precursors offer high vapor pressure but hinder sequential growth.
Purpose of the Study:
- To develop a sustained sequential growth method for organic MLD using high vapor pressure monofunctional precursors.
- To investigate the use of ozone-triggered ring-opening reactions for MLD.
- To explore the incorporation of fluorine into MLD films.
Main Methods:
- Utilized monofunctional aromatic precursors (phenol, trifluoromethylphenol, fluorinated benzaldehyde) in an ABC sequence with trimethylaluminum (TMA) and ozone.
- Evaluated hydrogen peroxide as a fourth step (ABCD sequence).
- Employed ellipsometry, infrared spectroscopy, X-ray reflectivity, and time-of-flight elastic recoil detection for characterization.
Main Results:
- Achieved self-limiting MLD processes between 75-150 °C.
- Observed decreased growth per cycle (GPC) with increasing temperature.
- Confirmed ring-opening reactions via in situ infrared spectroscopy.
- Successfully incorporated fluorine using fluorinated precursors.
Conclusions:
- High vapor pressure monofunctional precursors combined with ozone-triggered ring-opening reactions enable sustained sequential MLD growth.
- The developed method allows for controlled thin film deposition at moderate temperatures.
- Fluorine incorporation is feasible, expanding material possibilities for MLD.
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