Alexandra Boltasseva1
Purdue University1
Emerging plasmonic materials such as semimetals (transition metal nitrides and carbides), highly doped semiconductors, 2D and quasi-2D materials such as MXenes are playing an increasingly important role in emerging technologies for sustainable energy and photocatalysis [1]. For example, enhanced hot electrons generation in transition metal nitride nanoparticles compared to conventional materials such as gold enables more efficient light-to-electricity conversion [2,3]. MXenes, a class of 2D nanomaterials formed of transition metal carbides and carbon nitrides, form a promising material platform for tailorable nanophotonics. They offer a number of unusual properties and are being applied to realize novel electromagnetic shields, metal-ion batteries, super capacitors, lasers, and sensors. We utilized the plasmonic response of titanium carbide (Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub>) MXene thin films in the near infrared spectral window to create a metamaterial for broadband absorption [4] and explore the usage of MXenes for applications in photonics, energy harvesting, and desalination. Expanding the application realm for transition metal nitrides into sustainable, scalable technologies, we also demonstrated ultra-broadband light absorbers with titanium nitride (TiN) nanoparticles obtained through fast, large-scale and environmentally-friendly processes [5]. To advance photonic applications of novel materials further, we apply machine-learning-assisted data analysis techniques coupled with topology optimization and tailorable material platforms to obtain non-intuitive photonic designs for highly efficient optical devices and energy conversion.<br/><i>Support from the Air Force Office of Scientific Research (grant FA9550-17-1-0243) is acknowledged.</i><br/><b>References</b><br/>[1] Brongersma, M. L., Halas, N. J. & Nordlander, P. Plasmon-induced hot carrier science and technology. <i>Nature Nanotechnology</i> <b>10</b>, 25–34 (2015)<br/>[2] A. Naldoni, U. Guler, Z. Wang, M. Marelli, F. Malara, X. Meng, L. V. Besteiro, A. O. Govorov, A. V. Kildishev, A. Boltasseva, V. M. Shalaev, “Broadband Hot Electron Collection for Solar Water Splitting with Plasmonic Titanium Nitride,” Advanced Optical Materials 5 (15) 1601031 (August 2017)<br/>[3] A. Naldoni, F. Riboni, U. Guler, A. Boltasseva, V. M. Shalaev, A. V. Kildishev, “Solar-powered plasmon-enhanced heterogeneous catalysis,” Nanophotonics 5 (1) 112–133 (June 2016)<br/>[4] K. Chaudhuri, M. Alhabeb, Z. Wang, V. M. Shalaev, Y. Gogotsi, A. Boltasseva, “Highly Broadband Absorber Using Plasmonic Titanium Carbide (MXene),” ACS Photonics 5 (3) 1115-1122 (2018)<br/>[5] M. Li, U. Guler, Y. Li, A. Rea, E. K. Tanyi, Y. Kim, M. A. Noginov, Y. Song, A. Boltasseva, V. Shalaev, N. A. Kotov, “Plasmonic Biomimetic Nanocomposite with Spontaneous Subwavelength Structuring as Broadband Absorbers,” ACS Energy Letters 3, 1578–1583 (2018)