Carbon quantum dot modified electrospun TiO2 nanofibers for flexible formaldehyde gas sensor under UV illumination at room temperature

Abstract

A flexible gas sensor based on carbon quantum dot decorated TiO2 nanofibers (CQD/TiO2) was prepared by hydrothermal and electrostatic spinning methods to detect formaldehyde at room temperature. SEM, TEM, EDS, XRD and XPS were used to analyze the morphology, structure and composition of the composite. The gas sensing test results show that the working temperature of the material is reduced to room temperature by UV excitation, and subsequently, CQD/TiO2 exhibits a lower detection limit and faster response/recovery time for formaldehyde by carbon material modification. The flexibility test of CQD/TiO2 shows that the composite material of metal oxide and carbon material has a certain degree of flexibility. The enhanced sensing performance by UV excitation and CQD modification is attributed mainly to the photogenerated electron transfer and the formation of p-n heterojunctions. The modification of TiO2 with carbon quantum dots provides an experimental reference for the development of room-temperature flexible MOS-based formaldehyde sensors.