Ti doped violet tungsten oxide is doping titanium atoms into crystal lattice of VTO (W18O49) to form a new type of crystal lattice. Analysis indicates that after Ti entered the violet tungsten oxide crystal lattice and replaced W atoms, thus to interact with the surrounding neighboring atoms each other, the occupy of Ti atom’s electrons to the orbital will cause the overlapping of the electronic wave function, and further to affect the energy band structure of nanowires near Fermi level.
The main reasons for causing the changing of nanowires surface electronic properties of Ti doped violet tungsten oxide are Ti doping of hybrid orbitals and extra impurity state density, while this surface electronic properties changing which is occurred by doping regulates and controls the adsorption property of nanowires’ surface, and further to has an obvious impact on the gas sensitive properties of nanowires.
Compared to the saturated WO3, the superfine W18O49 with the stoichiometric ratio will perform the very obvious sensitive response to nitrogen dioxide (NO2), ammonia (NH3) and other gases under low temperature even though at room temperature, since it has particular lattice structure and high-density nanowire surface oxygen vacancies and other unsteady surface states, thereby W18O49 has the potential for utilizing in low power consumption, high sensitivity of gas sensors. So, we can conclude that, Ti doping is an effective way to modify the W18O49 nanowire based gas sensor.