Exploration Of Organic-inorganic Hybrid Perovskites Nanosheets For Surface-enhanced Infrared Spectroscopy

Infrared spectroscopy is extremely powerful for identifying the presence of specific structures,charge states,and orientations of organic molecules.However,its applications have been usually restricted because of the low sensitivity.After the surface-enhanced infrared absorption(SEIRA)was first found in 1980,mang materials such as the metal nanomaterials,graphene and the semiconductor materials were explored to realize SEIRA phenomenon.The substrates were modified to be more sensitive to the photon in infrared region.Accompanying with harvesting the photon,the energy was delivered from the photon to the substrate and then to the detected molecules absorbed on the substrate.During this process,the vibration amplitude of the detected molecules is increased,thereby enhancing the infrared signal of the detected object.The organic-inorganic perovskite enable the integration of organic and inorganic characteristics within a single molecule,providing the quantum well structure and the unique properties such as the excellent light harvesting and the high carrier mobility.The perovskite nanosheets prepared in this research by the reprecipitation method were characterized.The exploration of hybrid perovskite nanosheets for SEIRA spectroscopy of nitrobenzene aromatics and its application was also carried out.First,the hybrid perovskite nanosheets were characterized by IR,UV-Vis,PL and SEM.The band-gap structure was also explored.Second,the signal intensities of the nitrobenzene aromatics absorbed on the perovskite nanosheets were compared to the signal intensities caused on the blank substrate.The results showed that the hybrid perovskite nanosheets can significantly induce the SEIRA of adsorbed organic molecules.The enhancement effect was more obvious with the lower detection concentration.At last,the feasibility of qualitative and quantitative analysis of explosives by SEIRA spectroscopy based on perovskite nanosheets was investigated.When the analytes adsorbed on the surface of the perovskite,the experimental results showed a better sensitivity and a good linear relationship between the absorption intensity and the concentration of the detection.All the results proved the feasibility of this method.