Next Article in Journal
Phase Morphology and Mechanical Properties of Cyclic Butylene Terephthalate Oligomer-Containing Rubbers: Effect of Mixing Temperature
Next Article in Special Issue
Effects of Acoustic Modulation and Mixed Fuel on Flame Synthesis of Carbon Nanomaterials in an Atmospheric Environment
Previous Article in Journal
Aluminium Electrodeposition from Ionic Liquid: Effect of Deposition Temperature and Sonication †
Previous Article in Special Issue
Improvement of the Mechanical Properties of 1022 Carbon Steel Coil by Using the Taguchi Method to Optimize Spheroidized Annealing Conditions
Article Menu
Issue 9 (September) cover image

Export Article

Open AccessArticle
Materials 2016, 9(9), 715;

Formation and Entrapment of Tris(8-hydroxyquinoline)aluminum from 8-Hydroxyquinoline in Anodic Porous Alumina

Department of Applied Materials and Life Science, Graduate School of Engineering, Kanto Gakuin University, 1-50-1 Mutsuurahigashi, Kanazawa-ku, Yokohama, Kanagawa 236-8501, Japan
Authors to whom correspondence should be addressed.
Academic Editor: Shoou-Jinn Chang
Received: 31 May 2016 / Revised: 12 August 2016 / Accepted: 16 August 2016 / Published: 24 August 2016
(This article belongs to the Special Issue Selected Papers from ICASI 2016)
Full-Text   |   PDF [3101 KB, uploaded 24 August 2016]   |  


The formation and entrapment of tris(8-hydroxyquinoline)aluminum (Alq3) molecules on the surface of anodic porous alumina (APA) immersed in an ethanol solution of 8-hydroxyquinoline (HQ) were investigated by absorption, fluorescence, and Raman spectroscopies. The effects of the selected APA preparation conditions (galvanostatic or potentiostatic anodization method, anodizing current and voltage values, one- or two-step anodizing process, and sulfuric acid electrolyte concentration) on the adsorption and desorption of Alq3 species were examined. Among the listed parameters, sulfuric acid concentration was the most important factor in determining the Alq3 adsorption characteristics. The Alq3 content measured after desorption under galvanostatic conditions was 2.5 times larger than that obtained under potentiostatic ones, regardless of the adsorbed quantities. The obtained results suggest the existence of at least two types of adsorption sites on the APA surface characterized by different magnitudes of the Alq3 bonding strength. The related fluorescence spectra contained two peaks at wavelengths of 480 and 505 nm, which could be attributed to isolated Alq3 species inside nanovoids and aggregated Alq3 clusters in the pores of APA, respectively. The former species were attached to the adsorption sites with higher binding energies, whereas the latter ones were bound to the APA surface more weakly. Similar results were obtained for the Alq3 species formed from the HQ solution, which quantitatively exceeded the number of the Alq3 species adsorbed from the Alq3 solution. Alq3 molecules were formed in the HQ solution during the reaction of HQ molecules with the Al3+ ions in the oxide dissolution zone near the oxide/electrolyte interface through the cracks and the Al3+ ions adsorbed on surface of pore and cracks. In addition, it was suggested that HQ molecules could penetrate the nanovoids more easily than Alq3 species because of their smaller sizes, which resulted in higher magnitudes of the adsorption. View Full-Text
Keywords: anodic porous alumina; tris(8-hydroxyquinoline)aluminum; 8-hydroxyquinoline; absorption spectra; fluorescence spectra anodic porous alumina; tris(8-hydroxyquinoline)aluminum; 8-hydroxyquinoline; absorption spectra; fluorescence spectra

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Yamaguchi, S.; Matsui, K. Formation and Entrapment of Tris(8-hydroxyquinoline)aluminum from 8-Hydroxyquinoline in Anodic Porous Alumina. Materials 2016, 9, 715.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top