Mechanisms behind combustion chemistry in low-temperature solution process of nanomaterials

Abstract

Combustion synthesis has been widely used for low-temperature growth of metal-oxides nanomaterials. However, the mechanism behind its effectiveness remains unclear, because the current thermal analysis tools require the sample mass beyond 10 mg hardly achieved for nanomaterials. In this study, electrospinning was employed to fabricate massive In2O3 nanowires network films that enables directly study the thermal behaviours of combustion in nanomaterials via thermal analysis tools. We compared the thermal behaviours of electrospun nanomaterials and bulk materials with/without combustion. In the absence of combustion reaction in both, the nanowires shows a lower decomposition temperature than the bulk (500 versus 570 °C). In the presence of combustion reaction in both, it shows even lower decomposition temperature than the bulk (430 versus 500 °C). These indicate that combustion synthesis has two-fold mechanisms: first, it indeed provides internal thermal energy through combustion reaction for crystallizing the nanowires; second, the large surface area of the nanowires promotes the gases transport, which in turn accelerate the decomposition of organics in the nanowires. Based upon both mechanisms, a field effect transistor made of In2O3 nanowires network film was fabricated at 400 °C, whose Ion/Ioff reaches up to 105 with an Ion of 6 × 10−5 A.