2-D Photonic Crystal Sensors

Sensing technologies play a hugely important role in identifying and quantitating hazardous physical, chemical, or biological agents before they reach dangerous levels. An ideal sensor is one that can separately and selectively detect the largest subset of agent with high sensitivity. Current approaches to sensing such as mass spectrometry, fluorescence, and Raman spectroscopy rely on complex and expensive analytical techniques. Three-dimensional polymerized colloidal crystal array hydrogel sensors were developed as an approach to chemical sensing that does not require sample preparation and enables simple visual determination of chemical species and concentrations.

Schematic showing the fabrication of a 2-D photonic crystal for sensing applications. First, a water/propanol PS particle is dropped onto an Hg surface (1); then, the dispersion spreads to form a 2-D close-packed PS particle array as the solvent evaporates (2). A hydrogel film is polymerized around the 2-D array (3) and subsequently peeled from the glass substrate (4), allowing diffraction to be monitored visually (5).

Description

Pitt researchers have developed the first high diffraction-efficiency two-dimensional photonic crystals for molecular recognition and chemical sensing applications. These crystals were fabricated using a new approach in which an assembling monolayer is evaporated from a mercury surface, creating closely packed 2-D colloidal particle array capable of diffracting an incredible 80% of incident light. This array is transferred to a stimuli-responsive hydrogel thin film, shifting the diffraction wavelength, and enabling ultra-high diffraction efficiencies with potential uses in visual determination of analyte concentrations as well as attractive paints and coatings.

Applications

· Chemical detection and quantitating
· Attractive additive for paints and coatings

Advantages

· Ultrahigh diffraction efficiencies are achievable
· Able to control lattice spacing via pH, temperature, solvent, ion strength, or crosslinking density to fine-tune wavelength of diffracted light in visible wavelength range
· Optical signals are intense and easily monitorable
· Can be used on flat or curved surfaces or stacked to form a 3-D crystal sensor

Invention Readiness

Briefly indicate the stage of development, typically: in vivo, in vitro, prototype

IP Status

https://patents.google.com/patent/US9304074B2

Related Publication(s)

Zhang, J.-T., Wang, L., Luo, J., Tikhonov, A., Kornienko, N., & Asher, S. A. (2011). 2-D Array Photonic Crystal Sensing Motif. Journal of the American Chemical Society, 133(24), 9152–9155. https://doi.org/10.1021/ja201015c

Cai, Z., Smith, N. L., Zhang, J.-T., & Asher, S. A. (2015). Two-Dimensional Photonic Crystal Chemical and Biomolecular Sensors. Analytical Chemistry, 87(10), 5013–5025. https://doi.org/10.1021/ac504679n