Quantum dot fluorescent probe for pH detection as well as preparation method and application of quantum dot fluorescent probe

Abstract

The invention belongs to the field of inorganic luminescent materials. The invention relates to preparation of a calcium ion and europium ion co-doped bismuth oxysulfide nanocrystal and an applicationof the nanocrystal in pH detection. A quantum dot fluorescent probe for pH detection is formed by modifying the surface of a citric acid ligand with 10Ca / 6Eu: Bi2O2S nanocrystals, and the molar ratioof the citric acid ligand to the 10Ca / 6Eu: Bi2O2S nanocrystals is (2-10): 1. In the process of preparing the nanocrystal, alkaline earth calcium ions are added, so that the nucleation energy barrierof the bismuth oxysulfide nanocrystal is reduced, and the growth of the bismuth oxysulfide nanocrystal is further promoted. On the basis, through surface ligand exchange, the surface of the nanocrystalline is provided with the citric acid ligand. Along with the increase of the pH value, carboxyl in citric acid is gradually ionized, and the electronegativity of the surface of the nanocrystal is gradually reduced, so that the electronic layout on a charge migration band is inhibited, and the fluorescence intensity of Eu<3+> ions is further reduced. The simple fluorescence pH detection method provides a new idea for exploring a novel pH probe.

Description

technical field [0001] The invention belongs to the field of inorganic luminescent materials, and relates to the preparation of bismuth oxysulfide nanocrystal co-doped with calcium ions and europium ions and its application in pH detection. Background technique [0002] The pH value will affect the performance of materials, the activity of biological tissues, the growth of crops, etc. Therefore, pH detection is widely used in the fields of industry, agriculture, environment and biomedicine. The common pH detection method is mainly the electrochemical method based on the pH electrode, which has high accuracy, easy operation, and wide detection range, but the equipment size is large, the design is complicated, and it is not suitable for single-point detection. In contrast, fluorescent pH detection has many advantages, such as fast response, high spatial resolution, and non-contact long-distance measurement. So far, the main fluorescent pH probes include organic dyes, metal-or...

AI Technical Summary

Problems solved by technology

As the pH increases, the carboxyl groups in citric acid gradually ionize, which gradually reduces the electronegativity of the nanocrystal surface, inhibits the electronic layout on the charge transfer band, and reduces the Eu 3+ Fluorescence intensity of ions

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