A new concept for the eco-friendly structural colorization of anodic titania: Photonic crystal structure


DALMIŞ R., YILMAZ O., DİKİCİ T.

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, vol.631, 2021 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 631
  • Publication Date: 2021
  • Doi Number: 10.1016/j.colsurfa.2021.127748
  • Journal Name: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC
  • Keywords: Eco-friendly colorization, Structural color, Anodization, Photonic crystal, Anatase, PHOTOCATALYTIC ACTIVITY, SURFACE-PROPERTIES, BAND-GAP, TIO2, COLOR, DEGRADATION, ANODIZATION, FILMS, LASER, FABRICATION
  • Dokuz Eylül University Affiliated: Yes

Abstract

Structural colorization with photonic crystal structures draws high attention with fadeless bright color, combined with low toxic and eco-friendly features. It has been suggested for the first that the Titanium (Ti) surface coloration, which was not explained properly until now, is due to the photonic crystal structure. A dyeing process to be applied on the Ti/TiO2 will dampen their photocatalytic properties. However, the thin film grown on the Ti surface by the suggested anodizing process allows the formation of harmless structural colors and keeps photocatalytic performance. Ti substrates were anodized in HF and H3PO4 based solutions at voltage values between 10 V and 80 V. Structural, morphological, optical, and photocatalytic properties of the TiO2 thin films were characterized in order to determine anodization solution type and voltage. Similar to some butterfly wings, it is mentioned that the repeated lamellar and porous structures observed on the surfaces cause photonic crystal interactions with dielectric variations. It can be said that the anodization voltage value but not the anodization solution type can control the obtained structural violet, blue, yellow, orange, and red colors. Samples anodized at lower voltages exhibited better photocatalytic performance due to higher photon harvesting. Thus, we have proved in our study that both the photocatalytic property is not extinguished and that structural colors can be obtained.