Photochemical Synthesis of Large-Area Single-Crystal Gold Nanoplates on Amorphous Surfaces

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Prof. Svetlana Neretina of the University of Notre Dame will establish new photochemical routes for the synthesis of ultrathin gold layers on glass surfaces offering crystalline perfection, atomically flatness, and enhanced photo- and chemical-stability. Through improvements in the understanding of the nascent stages of crystal growth, Prof. Neretina aims to overcome the challenge of low crystallinity. In doing so, she will establish a low-cost platform for prototypic high-performance crystalline devices. The project will also open up opportunities for Prof. Neretina and her team to engage undergraduates in research activities and instill an interest and passion for science in the K−12 age group through the mentorship of high-school science fair projects and demonstrations performed at the annual Science Alive event. Current methods for the photochemical synthesis of noble metal nanoplates directly on substrate surfaces are reliant on plasmon-mediated growth modes and seed-induced symmetry-breaking controls that compel an otherwise isotropic material to grow along a two-dimensional pathway. With such growth modes being self-limiting in terms of the maximum lateral dimension achievable and substrate-seed fabrication requiring a heteroepitaxial relationship with a crystalline substrate, the growth of large-area nanoplates on amorphous surfaces is unfeasible using existing methodologies. Prof. Neretina’s research team will overcome these hurdles by defining and providing a mechanistic understanding of a new modality for the photochemical synthesis of gold nanoplates that distinguishes itself from current methods in that (i) the illumination of the growth solution, as opposed to the emerging nanoplate, is the key requirement for growth, (ii) growth persists from nanometer to millimeter length scales, and (iii) growth is initiated, not by heteroepitaxially aligned seeds, but by topographical features formed on glass substrates. Experiments will be performed that track and model nanoplate nucleation and growth under wavelength-dependent illumination, monitor the chemical fate of species within the growth solution, and identify the topographical features most favorable for nanoplate nucleation. Taken together, these studies will provide the means for producing high-aspect-ratio gold nanoplates with near-arbitrary size and provide the foundational knowhow that it could act as a generic route for the synthesis of a broad range of substrate-based nanomaterials. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.