Abstract: The present invention relates to nanofibers. In particular, the present invention relates to potassium niobate nanofibers. In an aspect of the present invention, there is provided a method of preparing the nanofibers, the method comprising: (a) dissolving niobium chloride and potassium sorbate in a solvent to obtain a first solution; (b) removing chloride precipitates formed from the first solution; (c) adding a polymer, for example polymethylmethacrylate or polyvinylpyrrolidone to the solution to obtain a second spinnable solution; and (d) electrospinning the spinnable solution to produce the fibers. The application also discloses the application of such nanofibers in the manufacture of a humidity sensor device by sputtering a metal such as Tantalum on top of the nanofibers.