Surface-enhanced IR Absorption Spectroscopy And Applications Based On Composite Films Of Hybrid Perovskite/PMMA

As same as the surface-enhanced Raman spectra, in surface-enhanced infrared absorption(SEIRA), the signal of organic compounds which absorbed on the surface of the nanometer metals base is several orders higher than which without metals. Currently, Au, Ag and some other transition-metal are the most important metals used in SEIRAS. Organic-inorganic hybrid perovskite(e.g.CH3NH3PbI3) as a semiconductor material with the special optical performance is widely used in solar cells fields. But, the moisture stability limits its application which is poor. It improved the moisture stability of hybrid perovskite by composited with PMMA. The substrates were characterized by IR, UV-Vis, PL and Scanning electron microscope. At the same time, the composite films were explored the moisture stability upon exposure to 75% relative humidity(25?). Four nitro aromatic compounds were used as probe to evaluate the infrared absorption effects. The composite films were used to detect the nitro aromatics in explosives extracts. The specific content of this paper is as follows:Firstly, Organic-inorganic hybrid perovskite were prepared by one-step solution deposition. And PMMA film was prepared by dip-coating.In addition, the substrates were characterized by IR, UV-Vis, PL and Scanning electron microscope. The results show that the film had the ability to capture the photoelectron and thermal stability. The morphology of the thin films was characterized by scanning electron microscopy. Results showed that: thin film is uniform, smooth, and quality is well.Secondly, the CH3NH3PbBr3 / PMMA, CH3NH3PbI3 / PMMA composite films were used as surface-enhanced infrared basement to explore the SEIRA effect of the nitro aromatic compounds. According to the calculation, for TNP, the enhancement factors reached 10, 18 respectively. For DNT, the enhancement factors reached 12, 5 respectively. For PNT, the enhancement factors reached 5. For PNP, the enhancement factors reached 8, 11 respectively.In the end, the CH3NH3PbI3 / PMMA composite films were used for tests of the four kinds of nitro aromatics enhance infrared absorption. The nitro stretching vibration peak around 1340 cm-1 was used for quantitative and qualitative analysis. The results showed that, TNP,DNT,PNT,PNP had good linear relationship with in 0.5~5mmol/L. The accuracy and precision of the method were also studied.In this experiment, DNT was detected in the extract of the explosive. At the same time, the possible interfering substances were also explored. The results showed that ammonium nitrate, sodium carboxymethyl cellulose and sodium silicate had no effect when toluene was used as extraction solvent to detect the infrared spectra of samples.