Edge computing has evolved to be a promising avenue to enhance system computing capability by offloading processing tasks from the cloud to edge devices. In this article, we propose a multi-layer edge computing framework called EdgeFlow. In this framework, different nodes ranging from edge devices to cloud data centers are categorized into corresponding layers and cooperate for data processing. EdgeFlow can deal with the trade-off between the computing and communication capabilities so that the tasks can be assigned to each layer optimally. At the same time, resources are carefully allocated throughout the whole network to mitigate performance fluctuation. The proposed open-source data flow processing framework is implemented on a platform that can emulate various computing nodes in multiple layers and corresponding network connections. Evaluated on the face recognition scenario, EdgeFlow can significantly reduce task finish time and perform more tolerance to run-time variations, compared with pure cloud computing, pure edge computing, and Cloudlet. Potential applications of EdgeFlow, including network function virtualization, Internet of Things, and vehicular networks, are also discussed at the end of this article.
The synthesised electrochromic polymers can exhibit a vegetable-green color at lower applied voltages and a soil-brown color in the oxidized-state, excellent solubility, superhydrophobicity, strong absorption, very fast switching times, and high stability.
In article number 1904494, Yueh-Lin Loo and co-workers demonstrate a near-infrared-harvesting perovskite solar cell with enhanced power-conversion efficiency as high as 21.6% and improved stability, with an operational half-life of 1900 h, by directly incorporating a multifunctional organic semiconductor that both extends light absorption and passivates defects in the perovskite active layers. This work provides a promising approach to prepare highly efficient and stable perovskites solar cells and opens a new application field for the rational design of narrow-bandgap organic semiconductors.
Abstract Typical lead‐based perovskites solar cells show an onset of photogeneration around 800 nm, leaving plenty of spectral loss in the near‐infrared (NIR). Extending light absorption beyond 800 nm into the NIR should increase photocurrent generation and further improve photovoltaic efficiency of perovskite solar cells (PSCs). Here, a simple and facile approach is reported to incorporate a NIR‐chromophore that is also a Lewis‐base into perovskite absorbers to broaden their photoresponse and increase their photovoltaic efficiency. Compared with pristine PSCs without such an organic chromophore, these solar cells generate photocurrent in the NIR beyond the band edge of the perovskite active layer alone. Given the Lewis‐basic nature of the organic semiconductor, its addition to the photoactive layer also effectively passivates perovskite defects. These films thus exhibit significantly reduced trap densities, enhanced hole and electron mobilities, and suppressed illumination‐induced ion migration. As a consequence, perovskite solar cells with organic chromophore exhibit an enhanced efficiency of 21.6%, and substantively improved operational stability under continuous one‐sun illumination. The results demonstrate the potential generalizability of directly incorporating a multifunctional organic semiconductor that both extends light absorption and passivates surface traps in perovskite active layers to yield highly efficient and stable NIR‐harvesting PSCs.
Accessing vertical orientation of two-dimensional (2D) perovskite films is key to achieving high-performance solar cells with these materials. Herein, we report on solvent-vapor annealing (SVA) as a general postdeposition strategy to induce strong vertical orientation across broad classes of 2D perovskite films. We do not observe any local compositional drifts that would result in impure phases during SVA. Instead, our experiments point to solvent vapor plasticizing 2D perovskite films and facilitating their surface-induced reorientation and concomitant grain growth, which enhance out-of-plane charge transport. Solar cells with SVA 2D perovskites exhibit superior efficiency and stability compared to their untreated analogs. With a certified efficiency of (18.00 ± 0.30) %, our SVA (BDA)(Cs0.1FA0.9)4Pb5I16 solar cell boasts the highest efficiency among all solar cells with 2D perovskites (n ≤ 5) reported so far.
Polymer donor F0 is fluorinated to F1 through converting methyl group to trifluoromethyl group on side chains. F1 exhibits remarkably improved performance in polymer solar cells with a highest PCE of 13.5%.
Two environmentally and thermally stable [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives, BOP-BTBT and DBOP-BTBT are successfully synthesized and analyzed as active layers in organic thin film transistors.
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