Molecular Layer Deposition of Pyrrone Thin Films by Oxidative Polymerization

Abstract

In this paper, the deposition of pyrrone thin film materials by molecular layer deposition (MLD) is reported for the first time using pyromellitic dianhydride (PMDA) and 3,3'‐diaminobenzidine (DAB) as monomers, and ozone as a promoting precursor. Besides ozone, the effect of water, hydrogen peroxide, and oxygen is also tested to promote the growth of MLD thin films. Ozone as a strong oxidant is the best reactant in this process. Two precursor pulsing sequences are tested and both result in pyrrone films. With the DAB+O3+PMDA sequence, growth per cycle (GPC) of 1.2 Å is obtained at 250–300 °C, whereas with the DAB+PMDA+O3 sequence, GPC of 1.5 Å is obtained. When only DAB and O3 are used, indamine films with GPC of 1.0 Å are obtained. The films are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. Chemical, thermal, and electrical properties of the films are also investigated. The films are stable in acidic and basic solutions and organic solvents, and they withstand 300 °C when annealed in air.

Precise Fabrication of Robust Conjugated Microporous Polymer Membranes via Oxidative Molecular Layer Deposition for Efficient Organic Solvent Nanofiltration

“…Typically, insufficient deposition temperatures may lead to precursor condensation, whereas elevated deposition temperatures can cause precursor desorption or decomposition, compromising film quality . As shown in Figure a, temperature profoundly impacts the growth rate in the oMLD process, with the GPC value generally reduced with rising deposition temperature, a trend commonly observed in most MLD systems, which can be rationalized by organic precursor desorption at elevated temperatures . The surface pores of AAO substrates are open during the initial deposition period; thus, certain deposition cycles are required to block the pore.…”