NETlab receives NSF CDS&E grant

Our lab has been awarded a three-year Computational and Data-enabled Science and Engineering (CDS&E) grant from the National Science Foundation to study thermal transport across interfaces between 2D materials and 3D substrates. Using first-principles methods, we will identify 2D-3D materials pairings that lead to better heat removal, enabling faster and higher-performance 2D nanoelectronics. For more info: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1902352

Discovering better 2D thermoelectrics

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

Schematic of the role of inelastic scattering in enhancing thermoelectric properties in 2D materials.

Our work on polymer thermoelectrics published in Nature Communications

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 on hopping transport in organic thermoelectrics published in Scientific Reports

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 work on thermal boundary conductance published in 2D Materials

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.

Cameron’s work explaining the effect of encapsulation on the thermal boundary conductance published in Advanced 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

Arnab’s article on dynamical thermal conductivity in graphene published in Phys Rev B

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 collaboration with UIC on heat dissipation in WSe2 published in ACS Applied Materials and Interfaces

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