Springer Handbook of Electronic and Photonic Materials
01 Jan 2017-Iss: 50, pp 1225-1256
TL;DR: In this paper, the authors proposed a method to identify the most likely SiH3 + SiH4 SiH 4 + Si H4 + H2 + H3 + H 2 + H 3 + H 4
Abstract: ion SiH3 + SiH4 SiH4 + SiH3 H + SiH4 H2 + SiH3
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TL;DR: In this article, the authors review the promise and current status of 2D transistors, and emphasize that widely used device parameters (such as carrier mobility and contact resistance) could be frequently misestimated or misinterpreted, and may not be the most reliable performance metrics for benchmarking two-dimensional transistors.
Abstract: Two-dimensional (2D) semiconductors have attracted tremendous interest as atomically thin channels that could facilitate continued transistor scaling. However, despite many proof-of-concept demonstrations, the full potential of 2D transistors has yet to be determined. To this end, the fundamental merits and technological limits of 2D transistors need a critical assessment and objective projection. Here we review the promise and current status of 2D transistors, and emphasize that widely used device parameters (such as carrier mobility and contact resistance) could be frequently misestimated or misinterpreted, and may not be the most reliable performance metrics for benchmarking 2D transistors. We suggest that the saturation or on-state current density, especially in the short-channel limit, could provide a more reliable measure for assessing the potential of diverse 2D semiconductors, and should be applied for cross-checking different studies, especially when milestone performance metrics are claimed. We also summarize the key technical challenges in optimizing the channels, contacts, dielectrics and substrates and outline potential pathways to push the performance limit of 2D transistors. We conclude with an overview of the critical technical targets, the key technological obstacles to the 'lab-to-fab' transition and the potential opportunities arising from the use of these atomically thin semiconductors.
347 citations
TL;DR: In this article, the authors provide an in-depth, critical review of ML-guided design and discovery of energy materials, a field where a novel material with superior performance (e.g., higher energy density, higher energy conversion efficiency, etc.) can have a transformative impact on the urgent global problem of climate change.
Abstract: DOI: 10.1002/aenm.201903242 materials in silico,[19–22] high computational costs and poor scaling still limit their effectiveness in exploring unconstrained chemical spaces and/or complex real-world materials. For instance, highthroughput DFT screening works typically limit the search space to hundreds or, at best, thousands of materials, while DFT simulations of materials are mostly limited to typically less than 1000 atoms, i.e., bulk crystals and isolated molecules. ML therefore offers a solution to the materials exploration problem, making predictions of new materials or properties from existing data, which in turn can drive the generation of more data that can be used to further refine the ML models. Here, we will provide an in-depth, critical review of MLguided design and discovery of energy materials, a field where a novel material with superior performance (e.g., higher energy density, higher energy conversion efficiency, etc.) can have a transformative impact on the urgent global problem of climate change. This review is structured along the steps in a typical workflow for materials ML model building, as shown in Figure 1. The next four sections will provide a concise overview of ML concepts designed to give the reader an appreciation of state-of-the-art techniques as well as resources for building ML models for materials. Section 6 reviews the actual application of ML techniques to the discovery and design of various classes of energy materials, from energy storage (e.g., batteries, fuel cells, etc.) to energy conversion (e.g., thermoelectrics, catalysis, etc.). The final section outlines our perspectives on various challenges and opportunities in ML for energy materials design.
282 citations
TL;DR: In this paper, the authors used time-domain flectance measurements of thermal conductivity along multiple directions of thin drop-cast PEDOT films to show that the thermal conductivities can be highly anisotropic (Λ∥ ≈ 1.0 W m −1 K −1 and Λ⊥ 0.3 W m−1 K−1 −1 for the in-plane and through-plane directions, respectively) when the electrical conductivity in the inplane direction is large (σ ≈ 500 S cm −1 ).
Abstract: Mixtures of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonate (PEDOT:PSS) have high electrical conductivity when cast from aqueous suspensions in combination with a high boiling-point cosolvent dimethyl sulfoxide (DMSO). The electronic component of the thermal conductivity of these highly conducting polymers is of interest for evaluating their potential for thermoelectric cooling and power generation. We find, using time-domain thermore- flectance measurements of thermal conductivity along multiple directions of thick (>20 μm) drop-cast PEDOT films, that the thermal conductivity can be highly anisotropic (Λ∥ ≈ 1.0 W m −1 K −1 and Λ⊥ ≈ 0.3 W m −1 K −1 for the in-plane and through- plane directions, respectively) when the electrical conductivity in the in-plane direction is large (σ ≈ 500 S cm −1 ). We relate the increase in thermal conductivity to the estimated electronic component of the thermal conductivity using the Wiedemann−Franz law, and find that our data are consistent with conventional Sommerfeld value of the Lorenz number. We use measurements of the elastic constants (C11 ≈ 11 GPa and C44 ≈ 17 GPa) of spin-cast PEDOT films and through-plane thermal conductivity (Λ⊥ ≈ 0.3 W m −1 K −1 ) of drop-cast and spin-cast films to support our assumption that the phonon contribution to the thermal conductivity does not change significantly with DMSO composition.
253 citations
TL;DR: In this paper, metal halide perovskites have shown great promise to enable highly efficient and low-cost tandem solar cells when being combined with silicon, achieving a certified power conversion efficiency (PCE) of 25.0%.
Abstract: Metal halide perovskites show great promise to enable highly efficient and low cost tandem solar cells when being combined with silicon. Here, we combine rear junction silicon heterojunction bottom cells with p–i–n perovskite top cells into highly efficient monolithic tandem solar cells with a certified power conversion efficiency (PCE) of 25.0%. Further improvements are reached by reducing the current mismatch of the certified device. The top contact and perovskite thickness optimization allowed increasing the JSC above 19.5 mA cm−2, enabling a remarkable tandem PCE of 26.0%, however with a slightly limited fill factor (FF). To test the dependency of the FF on the current mismatch between the sub-cells, the tandems' J–V curves are measured under various illumination spectra. Interestingly, the reduced JSC in unmatched conditions is partially compensated by an enhancement of the FF. This finding is confirmed by electrical simulations based on input parameters from reference single junction devices. The simulations reveal that especially the FF in the experiment is below the expected value and show that with improved design we could reach 29% PCE for our monolithic perovskite/silicon tandem device and 31% PCE if record perovskite and silicon cell single junctions could be combined in tandem solar cells.
199 citations
145 citations
Cites background from "Springer Handbook of Electronic and..."
...Consequently, the important roles in technologies such as data storage,[2] energy generation,[3,4] water purification,[5] and biomedicine[6] are all filled using traditional 3D magnets based on bulk crystals, amorphous alloys or nanostructures consisting of dozens of atomic layers....
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