Effects of Additive NH3 with Citric Acid in Precursor and Controlling Deposited Thickness for Growing MoO3 Crystals and Nanorods
In recent years, authors have successfully established a simple method for the production of fine single crystal-like MoO3 nanorod structures on substrates using a solution metal-organic decomposition (MOD) method to deposit film coatings from the solution precursors. However, to grow MoO3 nanorods by the MOD method, an accurate mechanism between MoO3 nanorod extension and precursor preparation (contents of precursor conditions) should be identified. Here, we demonstrated controllable MoO3 nanorods and plat-like α-MoO3 crystal growth based on as-deposited film thickness by using different citric acid (CA) and ammonia (NH3) ratios in the precursor solutions. The MoO3 nanorod growth mechanisms are discussed in detail with the precursor conditions and deposition film thickness; excellent results were achieved in controlling the film thickness by controlling the viscosities of the precursors. In addition, the effect of the amounts of CA and NH3 on the MoO3 nanorods and crystal growth was investigated. It was found that the NH3 plays an effective role in delaying the decomposition timing of CA, promotes the growth of MoO3 nanorods, and reduces the growth and increase of plate-like α-MoO3 crystals. The study obtained excellent results for the growth extension of MoO3 nanorods and plate-like α-MoO3 crystals, controlled by film thickness as the role of CA and NH3. The demonstrated strictly controlled MoO3 nanostructure forming process can be achieved with low energy consumption and low material resources, which can contribute significantly to the realization of a sustainable society.