A high-response formaldehyde sensor based on fibrous Ag-ZnO/In2O3 with multi-level heterojunctions

Timely detection of formaldehyde is pivotal because formaldehyde is slowly released from the indoor decorative materials, jeopardizing our healthy. Herein, a high-response formaldehyde gas sensor based on Ag-ZnO/In2O3 nanofibers was successfully fabricated. Compared with all the control samples, the hybrid exhibits superior sensitivity (0.65 ppm(-1)), excellent selectivity (>= 12.5) and durable stability (the deviation value <= 3%). Particularly, an ultra-high response value of about 186 towards 100 ppm of formaldehyde at 260 degrees C was achieved, heading the list of outstanding candidates. Additionally, the limit of detection is as low as 9 ppb. The enhanced gas sensing properties can be mainly attributed to multi-level heterojunctions (n-n heterojunction and Ohmic junction) and the spill-over effect of Ag, ultimately increasing the adsorption of gas molecules on the surface of sensing material. This work verifies that proper design of multi-level heterojunctions significantly upgrade the sensing performance.

Automated summary

A high-response formaldehyde gas sensor based on Ag-ZnO/In2O3 nanofibers was successfully fabricated, showing superior sensitivity, selectivity and stability, with an ultra-high response value towards formaldehyde. The low detection limit of the sensor can be mainly attributed to the proper design of multi-level heterojunctions, which significantly enhance the sensing performance.