一种基于量子点复合薄膜甲醛气体荧光传感器的研制

Development of fluorescence sensor for formaldehyde gas based on quantum dot composite film

研制基于聚乙烯醇(PVA)固定直径为5μm的二氧化硅小球制成的模板阵列和基团修饰量子点的甲醛气体传感器。通过模板法,利用量子点和20 nm表面修饰羟基二氧化硅的三维沉积制备敏感材料,并负载于PVA和二氧化硅微球的薄膜上,制备复合敏感膜。对比油胺、羧基、氨基修饰的量子点对甲醛的响应,表面修饰氨基的量子点对甲醛十分敏感,在120 s内其荧光强度从45000猝灭至40000。通过改进量子点成膜工艺实现对甲醛气体的特异性检测,开发新型微纳光学传感器件用于超低浓度气体的快速实时监测。以0~2μL/L低浓度甲醛气体的检测为例,利用荧光量子点的量子尺寸效应和表面修饰特性,实现甲醛气体的微量、高灵敏度、快速响应的实时监测。该仪器具有抗电磁干扰强、响应速度快、操作简单、制作成本低廉等优势,为基于荧光增强的量子点光学传感器在气体检测等方面的研究提供了新的制备思路和研究方向。

A formaldehyde gas sensor based on a template array made of silica spheres with 5μm diameter immobilized by polyvinyl alcohol(PVA)and group-modified quantum dots was developed.Through the template method,the sensitive material was prepared by three-dimensional deposition of quantum dots and 20 nm surface-modified silicon dioxide,and loaded on a thin film of PVA and silicon dioxide microspheres to prepare a composite sensitive film.Comparing the response of oleylamine,carboxyl,and amino modified quantum dots to formaldehyde,the surface-modified amino quantum dots were very sensitive to formaldehyde,whose fluorescence intensity was quenched from 45000 to 40000 within 120 s.Through the improvement of the quantum dot film forming process,the specific detection of formaldehyde gas was realized,and the new micro-nano optical sensor device was developed for rapid realtime monitoring of ultra-low concentration gas.It taken the detection of 0-2μL/L formaldehyde gas as an example,and used the quantum size effect and surface modification characteristics of fluorescent quantum dots to realized the realtime monitoring of formaldehyde gas with trace amounts,high sensitivity and rapid response.The instrument has the advantages of strong anti-electromagnetic interference,fast response speed,simple operation,and low production cost.It provides new preparation ideas and research directions for the research of fluorescence-enhanced quantum dot optical sensors in gas detection and other aspects.