Accurate prediction of band gap for new emerging materials is highly desirable for the exploration of potential applications. The band gaps of bulk and monolayer TMDs (MoS2, MoSe2, WS2, and WSe2) are calculated with the recently proposed by us GVJ‐2e method, which is implemented within DFT framework without adjustable parameters and is based on the total energies only. The calculated band gaps are in very good agreement with experimental ones for both bulk and monolayer TMDs. For monolayer MoS2, MoSe2, WS2, and WSe2, direct band gaps are predicted to be 1.88 eV, 1.57 eV, 2.03 eV, 1.67 eV correspondingly, and for bulk TMDs, indirect band gaps of 1.23 eV (MoS2), 1.09 eV (MoSe2), 1.32 eV (WS2), 1.21 eV (WSe2) are predicted. The GVJ‐2e method demonstrates good accuracy with mean absolute error (MAE) of about 0.03 eV for TMDs PL gaps (and 0.06 eV for QP gaps). GVJ‐2e method allows to equally accurately obtain band gaps for 3D and 2D materials. The errors of GVJ‐2e method are significantly smaller than errors of other widely used methods such as GW (MAE 0.23 eV), hybrid functional HSE (MAE 0.17 eV), TB‐mBJ functional (MAE 0.14 eV).

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Vertically aligned carbon nanotube (VA CNT) arrays are considered as promising thermal interface materials (TIMs) due to their superior out-of-plane thermal conductivities. However the air gaps between adjacent CNTs within the CNT array hinder the in-plane heat transfer, thus significantly degrading the thermal performance of VACNT-based TIMs. To improve the inter-tube in-plane thermal conduction within of VACNT arrays, we propose a novel three dimensional CNT (3D CNT) network structure, where the CNTs in a VACNT array are cross-linked by randomly-oriented secondary CNTs. Three different catalyst preparation methods for the secondary CNT growth are compared in terms of their ability to produce a dense network of secondary CNTs. Among the tested methods, the chemical impregnation method shows a denser 3D CNT network structure. The 3D CNT network grown using this method and is thus chosen for further thermal characterization via a framework especially developed for the evaluation of in-plane thermal properties of such devices. The temperature fields of the corresponding 3D CNT network under different heating powers are recorded using a 15 μm-resolution infrared thermal imaging system. The in-plane thermal conductivity is then derived from these fields using numerical fitting with a 3D heat diffusion model. We find that the in-plane thermal conductivity of the 3D CNT network is 5.40±0.92 W/mK, at least 30 times higher than the thermal conductivity of the primary VACNT array used to grow the 3D CNT network.

Metal films are seldom used as compliant electrodes for dielectric elastomer actuator (DEA) because they tend to restrain deformation of soft dielectrics. This work showed that silver film electrodes formed by electroless deposition (ELD) are indeed stretchable, and the DEA using ELD silver electrodes is able to generate an actuation up to 50% areal strain. Such ELD silver electrodes can self-heal, remain conductive at up to 33% uni-axial strain, and do not stiffen the dielectric layer as much as the sputtered silver electrodes. This metallized DEA can sustain a high breakdown field up to 350 MV/m, which is good for generating a large actuation force.