(6fs) Porous, Conductive Crystals: Expanding the 2D Materials Library with Metal-Organic Frameworks (MOFs)

My graduate research with Prof. Charles Lieber at Harvard University focused on the gas phase synthesis of inorganic, semiconductor nanowires, and specifically on exploiting previously unrealized, synthetic opportunities for growth on one-dimensional materials with applications in energy conversion and photonic devices. As first author on the project, I discovered and provided a mechanistic understanding for the ‘Plateau-Rayleigh crystal growth’ (Nature Nanotechnology 10, 345), which is unique to growth on one-dimensional substrates at the nanoscale. I extended the PR crystal growth to nanowire heterostructures (Nano Letters 16, 4713), and to growth on nanofabricated top-down Si substrates for photonic applications (in prep.). I also have significant experience with and co-led the electrical and optical characterization of photovoltaic devices fabricated from synthetically tuned nanowires (Nano Letters 12, 4971).

For my postdoctoral work, I sought out the opportunity to work with Prof. Mircea Dinca at MIT on conductive metal-organic frameworks (MOFs), which are hybrid inorganic/organic porous, crystalline materials that have demonstrated promise for energy storage, electrocatalysis and chemiresistive sensing. One of the biggest bottlenecks to understanding these new materials is an inability to grow sufficiently large crystals. I have improved our understanding for how these materials grow and, consequently, obtained much larger crystals for the porous MOF that currently has the highest conductivity to date. And by using nanofabrication techniques, I have fabricated, for the first time, single crystal electrical devices for both reported and new 2D MOFs.

My future research goals seek to develop materials that can efficiently store and convert energy, can detect molecules with high selectivity and sensitivity, and generate new platforms for fundamental transport studies. I think significant opportunities lie at the interface of porosity, chemistry and conductive, crystalline materials. My lab will pursue an understanding of how porous crystals conduct, and how interactions within these pores can influence their electrical and optical properties.

Teaching Interests:

I have extensive experience teaching undergraduate students and mentoring graduate students. For two years, I was a TA for Prof. Lieber’s “Nanoscience and nanotechnology” course and was asked to lecture for him in his absence.

Publications

1. T. Ozel, B.A. Zhang, R. Gao, R. W. Day, C. M. Lieber, and D. G. Nocera, “Electrochemical deposition of conformal and functional layers on high aspect ratio silicon micro/nanowires,” Nano Letters, 17, 4502-4507 (2017).

2. Y.-S. No, R. Gao, M. Mankin, R. W. Day, H.-G., Park, and C. M. Lieber, “Encoding active device elements at nanowire tips,” Nano Letters, 16, 4713-4719 (2016).

3. R. W. Day, M. N. Mankin, and C. M. Lieber, “Plateau-Rayleigh crystal growth of nanowire heterostructures: Strain-modified surface chemistry and morphological control in 1, 2 and 3 dimensions,” Nano Letters, 16, 2830-2836 (2016).

4. R. W. Day^*, M. N. Mankin^*, R. Gao, Y-S. No, S-K. Kim, D. Bell, H-G. Park and C. M. Lieber, “Plateau-Rayleigh crystal growth of periodic shells on one-dimensional substrates,” Nature Nanotechnology 10, 345-352 (2015).

5. M. N. Mankin, R. W. Day, R. Gao, Y-S. No, S-K. Kim, A. A. McClelland, D. C. Bell, H-G. Park, and C. M. Lieber, “Facet-selective epitaxy of compound semiconductors on faceted silicon nanowires,” Nano Letters 15, 4776-4782 (2015).

6. T. J. Kempa, S.-K. Kim, R. W. Day, H.-G. Park, D. Nocera and C. M. Lieber, “Facet-selective growth on nanowires yields multi-component nanostructures and photonic devices,” Journal of the American Chemical Society 135, 18354-18357 (2013).

7. T. J. Kempa, R. W. Day, S.-K. Kim, H.-G. Park and C. M. Lieber, “Semiconductor nanowires: A platform for exploring limits and concepts for nano-enabled solar cells,” Energy & Environmental Science 6, 719-733 (2013).

8. S.-K. Kim*, R. W. Day*, J. F. Cahoon*, T. J. Kempa, K.-D. Song, H.-G. Park and C. M. Lieber, “Tuning light absorption in core/shell silicon nanowire photovoltaic devices through morphological design,” Nano Letters 12, 4971-4976 (2012).

9. T. J. Kempa, J. F. Cahoon, S.-K. Kim, R. W. Day, D. C. Bell, H.-G. Park and C. M. Lieber, “Coaxial multishell nanowires with high-quality electronic interfaces and tunable optical cavities for ultrathin photovoltaics,” Proc. Natl. Acad. Sci. USA 109, 1407-1412 (2012).