Angle-Sensitive Photonic Crystals for Simultaneous Detection and Photocatalytic Degradation of Hazardous Diazo Compounds

Abstract

Congo Red (CR) and Amido Black 10B (AB-10B) are anionic diazo dyes, which are metabolized to produce a bioaccumulative and persistent carcinogen, benzidine. In this regard, an angle sensitive sensor composed of photonic crystal supported photocatalyst was fabricated for the simultaneous detection and photocatalytic degradation of diazo dyes from aqueous solutions. Reflectance spectroscopy was used in the detection of CR and AB-10B, which was based on the emergence of the incident angle dependent reflection peaks from the TiO2 coated two-dimensional photonic crystal (2D-PhC) surfaces and their subsequent quenching due to the presence of dye molecules whose absorbance peak intensity overlapped the reflection peak intensity of TiO2 at the respective angle. Interestingly, ultraviolet (UV) mediated photocatalytic degradation of CR and AB-10B was achieved using the same TiO2 coated 2D-PhC surfaces. 2D-PhC underneath the TiO2 layer was able to confine and localize the light on the TiO2 coated 2D-PhC surface, which enhanced the light absorption by dye molecules on the TiO2 surface and the photocatalytic efficiency in the degradation of CR and AB-10B. Finally, this proof-of-concept study demonstrated the fabrication of copolymer film based photonic crystal supported photocatalytic device, which can be used for developing miniaturized sensors competent in on-field detection and degradation of pollutants.

Floating TiO2-Cork Nano-Photocatalysts for Water Purification Using Sunlight

“…where A 0 is the initial absorbance of the RhB solution before irradiation and A t is the absorbance of RhB solution after a certain exposure time (t) [23,97]. Blank experiments (only RhB solution) were also carried out under solar simulating light and natural sunlight (Figures 9c and 10c).…”

A combination of angle insensitive stopband/passband filters based on one-dimensional hyperbolic metamaterial quasiperiodic photonic crystals

“…63,64 Devices with and without angle sensitivities have emerged as a new research focus in recent years. The former (previous) is useful for angle ltering and sensing, 65 while the latter is useful for waveguide and omnidirectional devices. 66 Kong et al 67 investigated thoroughly the angle insensitive multi-channel absorber made of non-linear plasma and complementary metamaterials.…”

The electromagnetic wave modulation based on single-frequency reflection in absorption with angle stability of hyperbolic metamaterials

“…In recent years, the angle sensitive and insensitive devices have become a new research hotspot. The former can be used for angle filtering and sensing [25], and the latter can be applied to waveguide and omnidirectional devices [26]. The angle insensitive multichannel absorber composed of nonlinear plasma and matching metamaterials were systematically discussed by Kong et al [27].…”