Ordered particle arrays are sought after for applications including electronics, optics, and solar cells. Innovation will require complex functional structures that are difficult to achieve with current methods. Understanding the mechanisms of particle assembly will enable spatial control and organization necessary for the development of functional arrays. Here, a hybrid top-down/bottom-up approach to particle assembly is presented. Interparticle and particle-field interactions were investigated using multi-component nanowires assembled in AC electric fields. By varying metal composition and/or selective etching of metal segments, we synthesized a variety of particle types. Control of the field profile was enabled through a lithographically patterned electrode geometry that facilitated the concentration of nanowires by funneling them towards regions of high field strength. Dielectric forces were manipulated through frequency and voltage variation, organizing nanowires parallel to the field lines within the electrode gap. Typically, the nanowires assembled into a structure that spanned the entire electrode gap. Electric field-directed assembly is especially useful for annealing structures by cycling the field on and off. Annealing allows individual particles to sample multiple interparticle interactions with varying van der Waals forces, settling into the most stable configuration. We took advantage of the reconfigurable nature of this system to produce ordered, particle-dense structures. This dynamic system could be further investigated for use as a rapidly configurable material.

Electric field-directed nanowire assembly

249th National Meeting (2015)

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