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• Gram-scale GQDs of good quality were synthesized via an improved AOP reaction. • The method provides advantages of low-cost, convenience, and sustainability. • The red-emitting GQDs are able to penetrate a healthy mouse skin efficiently. • White light-emitting composite films with a high QY of 24% have been prepared. Graphene quantum dots (GQDs) have been demonstrated of great potential and benefits in the fields of bioimaging and white light-emitting-diodes (WLEDs). However, it is still highly demanding at the current level to solve the dilemma of achieving high-yield GQDs of good quality and superior fluorescent property using low-cost sustainable and industrializable production procedure. In this work, we for the first time report the gram-scale synthesis of well-crystalline GQDs with ultra-small size based on thermal-driven Advanced Oxidation Process (AOP) under facile green hydrothermal conditions. The average yield calculated from 20 trials reached up to 60%, and the average size of the dots was measured to be ~3.7 nm. Furtherly, GQDs with the photoluminescence (PL) emission of blue, green, yellow, orange, and red have been prepared by expanding the π-conjugation and introducing graphite nitrogen in the carbon skeleton based on chemical structure engineering. The PL-tunable GQDs have an average size distribution of 2–5 nm and a lamellar structure of 2–6 layers. Structure analysis results have indicated that the red shift of PL emission is attributed to bandgap narrowing. This approach successfully converts the easily available and cheap precursor into high-valued products with great application potentials. The PL-tunable GQDs have been successfully used as fluorescent probes of good biocompatibility for in vitro/ in vivo bio-imaging and to produce highly-photostable white-light-emitting composite film with a quantum yield (QY) of 24%. [ABSTRACT FROM AUTHOR]

Mesh denoising is a crucial research topic in geometric processing, as it is widely used in reverse engineering and 3D modeling. The main objective of denoising is to eliminate noise while preserving sharp features. In this paper, we propose a novel denoising method called Attention Enhanced Dual Mesh Denoise (ADMD), which is based on a graph neural network and attention mechanism. ADMD simulates the two-stage denoising method by using a new training strategy and total variation (TV) regular term to enhance feature retention. Our experiments have demonstrated that ADMD can achieve competitive or superior results to state-of-the-art methods for noise CAD models, non-CAD models, and real-scanned data. Moreover, our method can effectively handle large mesh models with different-scale noisy situations and prevent model shrinking after mesh denoising. • We introduce a novel mesh denoising algorithm based on graph convolution. • We design a self-attention module to extract global features and a dual cross-attention module for feature fusion. • Some new techniques are proposed to improve the ability of the network. [ABSTRACT FROM AUTHOR]

Abstract Novel vertical light-emitting diodes (VLEDs) decorated with N-doped graphene quantum dots (N-GQDs) have been fabricated, based on the metal organic chemical vapor deposition method (MOCVD), wafer bonding technique, laser lift-off (LLO) technique, inductively coupled plasma (ICP) etching and impregnation processing. There is an obvious luminescence enhancement and resistance reduction for VLEDs after coating N-GQDs. The results show an improvement of light output power (LOP), dependent on the improvement of optical extraction efficiency and current spreading. The improvement of external quantum efficiency (EQE) is mainly owing to the roughened surfaces. Meanwhile, an enhancement of electroluminescence (EL) intensity and photoluminescence (PL) intensity has been achieved when the VLEDs were immersed in 0.9 mg/mL of N-GQDs solution, 4 times that of bare VLEDs. After coating N-GQDs, the performance of VLEDs is greatly improved, which could be attributed to the photons recovered by extracting light from waveguide modes. Highlights • Novel vertical light-emitting diodes (VLEDs) were fabricated by coating N-doped graphene quantum dots (N-GQDs) on the surface. • The existence of N-GQDs on the surface of VLEDs can significantly improve the current spreading. • The VLEDs after being coated with N-GQDs exhibited a 25% improvement in EQE. [ABSTRACT FROM AUTHOR]

In‐situ UV‐irradiation activation leads to an intense visible‐light absorption of up to 700 nm in ethylene glycolate‐stabilized TiO2(B) nanosheets. It is ascribed that the creation of abundant subsurface/lattice oxygen vacancies and Ti3+ centers, along with UV‐induced breakdown of Ti−O bonds between ethylene glycolate and TiO2(B). Consequently, the enhanced and stable visible‐light‐driven photocatalytic H2 evolution is obtained on defect‐rich TiO2(B) nanosheets. [ABSTRACT FROM AUTHOR]

Cover Feature: In-situ Photosynthetic Route to Tailor Point Defects in TiO2(B) Nanosheets for Visible Light-Driven Photocatalytic Hydrogen Production (ChemCatChem 17/2019) Shows I in-situ i UV-irradiation activation for creating abundant subsurface/lattice oxygen vacancies and Ti SP 3+ sp centers in ethylene glycolate-stabilized TiO SB 2 sb (B) nanosheets. In their Communication, Ping Wang, Xianying Wang and co-workers explain that along with UV-induced breakdown of Ti-O bonds between ethylene glycolate and TiO SB 2 sb (B) nanosheets, the obtained defect-rich nanosheets exhibit an extended absorption band of up to 700 nm and greatly enhanced visible-light photoactivity for H SB 2 sb evolution. [Extracted from the article]

Nitrogen doped graphene quantum dots (NGQDs) were successfully prepared via a hydrothermal method using citric acid and urea as the carbon and nitrogen precursors, respectively. Due to different post-treatment processes, the obtained NGQDs with different surface modifications exhibited blue light emission, while their visible-light absorption was obviously different. To further understand the roles of nitrogen dopants and N-containing surface groups of NGQDs in the photocatalytic performance, their corresponding composites with TiO2 were utilized to degrade RhB solutions under visible-light irradiation. A series of characterization and photocatalytic performance tests were carried out, which demonstrated that NGQDs play a significant role in enhancing visible-light driven photocatalytic activity and the carrier separation process. The enhanced photocatalytic activity of the NGQDs/TiO2 composites can possibly be attributed to an enhanced visible light absorption ability, and an improved separation and transfer rate of photogenerated carriers. [ABSTRACT FROM AUTHOR]