Two-dimensional nanomaterials have emerged as promising candidates for next-generation electronics and optoelectronics [1], but advances in scalable nanomanufacturing are required to exploit this potential in real-world technology. This talk will explore methods for improving the uniformity of solution-processed two-dimensional nanomaterials with an eye toward realizing dispersions and inks that can be deposited into large-area thin-films [2]. In particular, density gradient ultracentrifugation allows the solution-based isolation of graphene [3], boron nitride [4], montmorillonite [5], and transition metal dichalcogenides (e.g., MoS₂, WS₂, ReS₂, MoSe₂, WSe₂) [6,7] with homogeneous thickness down to the atomically thin limit. Similarly, two-dimensional black phosphorus is isolated in organic solvents [8] or deoxygenated aqueous surfactant solutions [9] with the resulting phosphorene nanosheets showing field-effect transistor mobilities and on/off ratios that are comparable to micromechanically exfoliated flakes. By adding cellulosic polymer stabilizers to these dispersions, the rheological properties can be tuned by orders of magnitude, thereby enabling two-dimensional nanomaterial inks that are compatible with a range of additive manufacturing methods including inkjet [10], gravure [11], screen [12], and 3D printing [13]. The resulting printed two-dimensional nanomaterial structures show promise in several applications including photodiodes [14], anti-ambipolar transistors [15], gate-tunable memristors [16], and heterojunction photovoltaics [17,18].

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[2] E. B. Secor, et al., Journal of Physical Chemistry Letters, 6, 620 (2015).

[3] A. A. Green, et al., Nano Letters, 9, 4031 (2009).

[4] J. Zhu, et al., Nano Letters, 15, 7029 (2015).

[5] J. Zhu, et al., Advanced Materials, 28, 63 (2016).

[6] J. Kang, et al., Nature Communications, 5, 5478 (2014).

[7] J. Kang, et al., Nano Letters, 16, 7216 (2016).

[8] J. Kang, et al., ACS Nano, 9, 3596 (2015).

[9] J. Kang, et al., Proc. Nat. Acad. Sci. USA, 113, 11688 (2016).

[10] E. B. Secor, et al., Journal of Physical Chemistry Letters, 4, 1347 (2013).

[11] E. B. Secor, et al., Advanced Materials, 26, 4533 (2014).

[12] W. J. Hyun, et al., Advanced Materials, 27, 109 (2015).

[13] A. E. Jakus, et al., ACS Nano, 9, 4636 (2015).

[14] D. Jariwala, et al., Proc. Nat. Acad. Sci. USA, 110, 18076 (2013).

[15] D. Jariwala, et al., Nano Letters, 15, 416 (2015).

[16] V. K. Sangwan, et al., Nature Nanotechnology, 10, 403 (2015).

[17] D. Jariwala, et al., Nano Letters, 16, 497 (2016).

[18] T. A. Shastry, et al., ACS Nano, 10, 10573 (2016).