(321f) Using Metal Nanocrystal Photothermal Heating to Drive Colloidal Semiconductor Nanowire Growth

Advances in precise nanomaterial synthesis have led to new technologies that span medicine, computing, and energy. In traditional nanomaterial syntheses, global resistive heating of high boiling point solvents drives precursor decomposition and nanomaterials growth under isothermal conditions. However, temperature constraints due to solvent boiling points prevent the synthesis of many materials by restricting access to high temperature structural phases and limiting available precursor chemistries. Accessing higher temperatures to mitigate these issues requires expensive reactors with complex temperature and pressure management systems. However, many reactions still remain inaccessible to colloidal chemistry.

Here, we present a new paradigm for driving colloidal nanomaterials synthesis through local photothermal heating, rather than global resistive heating. We show that metal nanocrystals dispersed in solution can act as both light absorbers to locally heat and decompose reactants as well as directors for the solution-liquid-solid growth of semiconductor nanowires. Heat transport calculations combined with thermographic imaging show that the Young-Laplace effect suppresses boiling to enable high temperature nanomaterial growth via collective local heating. This local heating, rather than traditional global resistive heating, removes restrictions on synthesis equipment and permits the growth of nanomaterials on the benchtop. To highlight this advantage, we demonstrate continuous colloidal nanowire growth with this process.