Here is our newest article, just accepted in the new open-access Journal of Physics: Materials, in which we identify materials properties that will lead to higher thermoelectric power factors in two-dimensional materials. This work will help researchers discover new 2D TEs in the future: https://doi.org/10.1088/2515-7639/ab4600
Our article on “Tuning charge transport dynamics via clustering of doping in organic semiconductor thin films” has been published https://t.co/N0G7usJYL9 in Nature Communications. This was a collaboration with with Dhandapani Venkataraman and my student Meenakshi Upadhyaya on the impact of dopant clustering on the TE performance of polymers. This work was featured in a UMass News article: https://www.umass.edu/newsoffice/article/how-capture-waste-heat-energy-improved and several scientific news outlets (EurekaAlert, Phys.org, Science Daily, etc.)
Meenakshi’s work, in collaboration with Prof. Venkataraman’s ALIEN group in UMass Chemistry, studies how to leverage disorder in amorphous organic materials such as polymers to improve their thermoelectric performance. The paper is open access and free to read via Scientific Reports: https://doi.org/10.1038/s41598-019-42265-z
Cameron’s research on the thermal boundary conductance between monolayers of 2-dimensional materials and 3D substrates has been published in IOP’s journal 2D Materials (link here: https://doi.org/10.1088/2053-1583/ab04bf ). In it, we show that the TBC is driven by the vibrational densities of states of the two materials and we identify trends in materials properties as well as the ideal substrate for each 2D layer. Amorphous substrates generally fare better than crystalline because of the so-called “boson peak” of excess low-frequency vibrational modes, which matches well with the flexural phonons in 2D materials.
In collaboration with the Salehi-Khojin group at UIC, we studied the effect of encapsulation on the thermal boundary conductance (TBC) between few-layer MXene (Ti3C2) and the substrate. Cameron’s first-principles simulations explain that encapsulating the MXene with amorphous AlOx nearly doubles the TBC to the substrate because the encapsulation dampens the long-wavelength flexural phonon modes that are responsible for most of the 2D-3D heat transfer. The work has been accepted for publication in the prestigious Advanced Materials (impact factor ~22): https://doi.org/10.1002/adma.201801629
Our recent work on the dynamical thermal conductivity in graphene nanoribbons shows that frequency-dependent thermal transport arises in the hydrodynamic regime. Thermal conductivity resembles a low-pass filter while the normal and resistive components of the heat flux are out of phase with each other. The work is now published in Physical Review B: https://doi.org/10.1103/PhysRevB.98.024303
Our recent work aimed at understanding the heat dissipation, thermal boundary conductance, and Raman spectra in the transition metal dichalcogenide WSe2, done in collaboration with Selehi-Kkhojin’s group at UIC, has been published in ACS Applied Materials and Interfaces. Congratulations Arnab and Cameron, who contributed theory and first-principles simulation of the decay paths of Raman active optical phonons and the thermal boundary conductance between multi-layer WSe2 and the substrate.
Full paper available here: https://dx.doi.org/10.1021/acsami.8b04724
Prof. Zlatan Aksamija was recently quoted in a Science News story about why scientists are studying how 2-D materials such as graphene behave at high temperatures. In the February 13 edition of Science News, Aksamija said that commonly used silicon-based electronics are “hitting a brick wall” regarding how much smaller they can be manufactured, and that 2-D materials could be ideal for constructing the next generation of tiny devices: