Quinizarin: a large aromatic molecule well suited for atomic layer deposition

Area of Science:

• Materials Science
• Nanotechnology
• Organic Chemistry

Background:

• Atomic layer deposition (ALD) and molecular layer deposition (MLD) are powerful techniques for creating complex material structures.
• Combining organic and inorganic components via MLD is crucial for advanced optical materials, but large aromatic molecules often pose sublimation and reactivity challenges.
• Developing new organic precursors is essential for applications in dye-sensitized solar cells, luminescence, and organic electronics.

Purpose of the Study:

• To investigate the potential of quinizarin, a highly absorbing aromatic dye, as a precursor for molecular layer deposition (MLD).
• To explore the deposition of hybrid films using quinizarin and assess their optical properties and luminescence.
• To evaluate strategies for incorporating quinizarin into MLD films for potential applications in advanced materials.

Main Methods:

• Utilized molecular layer deposition (MLD) with trimethylaluminum and quinizarin to deposit hybrid films.
• Characterized the deposited films' optical absorption spectra and luminescence.
• Investigated film properties using multilayer structures and co-pulsing with pentaerythritol to achieve luminescence.

Main Results:

• Successfully deposited strongly colored pink hybrid films using quinizarin and trimethylaluminum at 175 °C with a growth rate of 0.28 nm/cycle.
• The deposited hybrid films exhibited optical absorption spectra similar to quinizarin solutions but lacked luminescence.
• Attempts to achieve luminescence through dilution with pentaerythritol (multilayer or co-pulsing) were unsuccessful.

Conclusions:

• Quinizarin's low sublimation temperature, good reactivity, and conjugated system make it a promising candidate for MLD.
• While hybrid films show potential for optical applications, luminescence was not achieved under the tested conditions.
• Further research into solid-state hybrid and organic films based on quinizarin is warranted for various technological pathways.