Two-dimensional (2D) materials offer novel electronic and optical properties, but scalable methods for producing optical quality metallic 2D structures have yet been elusive. 2D transition metal carbides and nitrides, known collectively as MXenes, are highly conductive and water-dispersible, suggesting their utility as solution-assembled optoelectronic and plasmonic materials. Here we show that 2D Ti3C2 can be assembled from aqueous solutions into optical quality, plasmonic thin films that, at 6500 Siemens-per-centimeter, surpass the conductivity of other solution-processed 2D materials. We show that this can be attributed to their metal-like free-electron densities and highly oriented structure. Simultaneously they exhibit a high degree of transparency to visible light. The onset of free-electron plasma oscillations above 1130 nanometers is observed by ellipsometry. Ti3C2 is therefore a potential building-block for plasmonic applications at near-infrared wavelengths and constitutes the first example of a new class of solution-processed, carbide-based 2D optoelectronic materials. Moreover, we demonstrate that MXene can be lithographically patterned using simple solution chemistries.

Plasmonic films from solution-processed 2D titanium carbide

252nd National Meeting (2016)

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