Modification of indium oxide nanofibers by polyoxometalate electron acceptor doping for enhancement of gas sensing at room temperature

Abstract Indium oxide (In2O3) is a most popular sensor material due to its relatively low resistance and easy synthesis. However, the development of In2O3-based gas sensors is still suffering from high carrier recombination rate. Polyoxometalates (POMs), which have been regarded as efficient electron acceptors, can catch the photo-induced electrons in semiconductors and suppress carriers recombination. Herein, POM (PW12)-doped In2O3 composite nanofibers were successfully synthesized via electrospinning combined with subsequent calcination process. For the first time we investigated on the gas sensing performances of POM-doped In2O3 composite based on the photoconductive change at room temperature. The test results demonstrate that In2O3/PW12 composite nanofibers exhibit a higher photoconductivity and enhanced gas sensing response toward formaldehyde compared with the pure In2O3 nanofibers. These could be ascribed to the migration of photogenerated electrons from In2O3 to PW12. Thus the recombination of photo-induced carriers in In2O3 can be obviously suppressed and the utilization of electrons can be increased as a result. The research results reveal a new idea for developing high-performance gas sensors based on In2O3 by introducing POMs.