Research On The Application Of Photonic Crystals In The Rapid Detection And Analysis Of Environmental Organic Pollutants

Organic pollutants are one of the most important environmental contaminants,which seriously threaten public health and the ecosystem.The development of a highly specific ultra-sensitive method for the detection of organic pollutants in the environment is of great significance to improving public health.Photonic crystals are widely used in the specific detection of various biological analytes and environmental pollutants due to their simple structure,convenient preparation,and low cost.However,there are still many challenges in the detection of environmental pollutants and biological analytes using photonic crystals,such as low sensitivity,time-consuming detection,and poor reproducibility.To realize ultrasensitive real-time detection of organic pollutants in the environment by photonic crystals,this paper combines different types of photonic crystal materials with Raman spectroscopy to detect organic pollutant molecules in the environment.The main contents are summarized as follows:(1)Monodisperse SiO2 nanoparticles with different sizes were successfully prepared by the modified Stober method.The patterned photonic crystals were fabricated by a spraying method,and the Ag nanoparticles were sputtered on the surface of the photonic crystals by a vacuum coater to obtain a hydrophobic photonic crystal microchip(HPCM)with surface-enhanced Raman scattering(SERS)activity.The relationship between the different Ag film thickness and wettability and SERS activity of photonic crystal microchip was studied by using fiber optic spectrometer,scanning electron microscope,atomic force microscope,contact angle measuring instrument,and laser Raman spectrometer.At the same time,the photonic bandgap(PBG)of the photonic crystals was coupled with the wavelength of the Raman laser to enhance the interaction between the laser and the substance adsorbed on the surface of the photonic crystals,and further improve the SERS signal,thereby realizing ultra-sensitive detection of trace organic pollutants in water.The experimental results showed that the fabricated HPCM had a potential application in terms of trace organic compounds screening.(2)The gold nanoparticles-doped photonic crystal microspheres(AuNP-PC microspheres)were synthesized by the microfluidic technique.The morphology and element distribution of AuNP-PC microspheres were characterized by scanning electron microscopy and energy dispersive spectroscopy.Raman spectroscopy was used to investigate the SERS activity of AuNP-PC microspheres at different calcination temperatures.Since the doping of Au nanoparticles does not change the periodic arrangement of SiO2 nanoparticles,AuNP-PC microspheres still exhibit excellent optical properties.In order to further improve the sensitivity of the SERS material,the PBG was coupled with the Raman laser wavelength,which improved the interaction between the surface material of the photonic crystal and the Raman laser,and realized the large-span improvement of the SERS signal.As the photonic crystal microspheres could be completely immersed in the analytical solution,they could rapidly adsorb the analyte for SERS detection.In addition,the laser Raman spectrometer was used to prove the Raman signal uniformity of AuNP-PC microspheres,which indicates the stability of the material in analysis and detection.The experimental results showed that the prepared AuNP-PC microspheres can realize online ultrasensitive detection of environmental organic pollutants.