Doping-free bandgap tuning in one-dimensional Magnéli-phase nanorods of Mo4O11

Abstract

We synthesized one-dimensional (1D) Magnéli-phase nanorods of Mo₄O₁₁ using the hot filament metal–oxide vapor deposition technique. The 1D Magnéli-phase Mo₄O₁₁ nanorods synthesized at 1000, 1050, 1100, 1150, and 1200 °C contain varying combinations of two orthorhombic (α) and monoclinic (η) phases, and various mixtures of Mo⁴⁺, Mo⁵⁺ and Mo⁶⁺ cations, while those synthesized at a higher temperature look bluer. The shifts of the transmittance maximum and absorbance minimum of the 1D Magnéli-phase Mo₄O₁₁ nanorods are inversely and linearly proportional to the elevated temperature, verifying that the bandgaps (E_g) are inversely proportional to the elevated temperature. The bandgap (E_g) of the 1D Magnéli-phase Mo₄O₁₁ nanorods can be tuned by simply controlling the synthesis temperature without doping with other materials, giving the 1D Magnéli-phase Mo₄O₁₁ nanorods good potential for use in optoelectronic nanodevices and bandgap engineering.