Flame assisted synthesis of nanostructures for device applications

ABSTRACT Development of fabrication technologies for three-dimensional structuring and integration of nanomaterials in devices is important for a broad range of applications, including next-generation high energy density batteries, super(de)wetting and biomedical coatings, and miniaturized biomedical diagnostics. Amongst various nanofabrication approaches, the flame synthesis route accounts for some of the first man-made nanomaterials and industrial production of various nanoparticle commodities such as carbon black, fumed silica, and pigmentary titania. In the past two decades, flexibility in nanomaterials and facile fabrication of nanostructured films by aerosol self-assembly has motivated the exploration of this technology for device applications. In this review, we present a perspective of recent progress in flame-assisted nanofabrication and its application to emerging technologies. The fundamentals of flame synthesis will be briefly reviewed to evaluate trends in flame reactor designs and directions for improvements. A selection of exemplary flame-made nanostructures will be presented across the major categories of catalysis, energy conversion devices, membranes and sensors, highlighting weakness and strengths of this synthesis route. We will conclude with an outlook towards possible implementation of flame-assisted self-assembly as a scalable tool for nanofabrication in emerging devices and a critical assessment of the persisting challenges for its broader industrial uptake. Graphical Abstract