PNNL

Abstract

Hierarchical and other advanced materials have attracted increasing attention due to their unique physical and chemical properties, which strongly depend on morphology and size.1-2 These materials have been applied in important technological fields such as energy, catalysis, optical devices, water purification, pollutant removal, CO2 sequestration, and biomedicine.3-7 Particle-based crystallization and self-assembly of molecules are important pathways to synthesize advanced materials of complex structures.8-11 Unlike monomer-by-monomer addition or Ostwald ripening, particle-based crystallization occurs via particle-by-particle addition, to form larger crystals or clusters.8, 12 To date, numerous advanced materials have been synthesized in the lab using particle-based crystallization. Examples include metals such as Pt, Pd, Au, Ag, and Cu;13 alloys such as Pt-Ni, Pt-Cu, Pt-Fe, and Au-Ag;14 metal oxides such as ZnO, TiO2, CuO, and a-Fe2O3, Fe3O4;15-19 and metal sulfides such as PbS, PbSe, ZnS, and CdS.20-21 In addition, particle aggregation-based crystallization has been observed in nature, such as in various geological and biological minerals including calcite, collagen, and others.22-24 Different from the particle-based crystallization, self-assembly of molecules has also been used to build advanced materials such as molecular clusters and nanoparticles. For instance, advanced luminescent materials have been prepared by aggregation-induced emission (AIE) of intrinsically non-emissive molecules.25-26 One of the challenges facing this fast-growing field of advanced materials is to develop a fundamental understanding of the interactions between particles or molecules in a growth medium and the resulting response dynamics.