Development of Coral Investigation System Based on Semantic Segmentation of Single-Channel Images.

Among aquatic biota, corals provide shelter with sufficient nutrition to a wide variety of underwater life. However, a severe decline in the coral resources can be noted in the last decades due to global environmental changes causing marine pollution. Hence, it is of paramount importance to develop and deploy swift coral monitoring system to alleviate the destruction of corals. Performing semantic segmentation on underwater images is one of the most efficient methods for automatic investigation of corals. Firstly, to design a coral investigation system, RGB and spectral images of various types of corals in natural and artificial aquatic sites are collected. Based on single-channel images, a convolutional neural network (CNN) model, named DeeperLabC, is employed for the semantic segmentation of corals, which is a concise and modified deeperlab model with encoder-decoder architecture. Using ResNet34 as a skeleton network, the proposed model extracts coral features in the images and performs semantic segmentation. DeeperLabC achieved state-of-the-art coral segmentation with an overall mean intersection over union (IoU) value of 93.90%, and maximum F1-score of 97.10% which surpassed other existing benchmark neural networks for semantic segmentation. The class activation map (CAM) module also proved the excellent performance of the DeeperLabC model in binary classification among coral and non-coral bodies.

Functionalized Ionic Liquid-Crystal Additive for Perovskite Solar Cells with High Efficiency and Excellent Moisture Stability.

Organic-inorganic hybrid perovskite solar cells (PSCs) have emerged as a promising candidate for next-generation solar cells. However, the limited stability of PSCs hampers their practical applications. In this work, for the first time, a functionalized π-conjugated ionic liquid crystal (ILC), 4'-(N,N,N-trimethyl ammonium bromide hexyloxy)-4-cyanobiphenyl (6CNBP-N), is developed as a novel chemical additive to obtain CH3NH3PbI3 (MAPbI3) PSCs with high efficiency and excellent moisture stability. This 6CNBP-N ILC possesses the characteristics of ionic liquids and liquid crystals. The inclusion of the 6CNBP-N ILC can effectively improve the quality and stability of perovskite films, reduce the trap-state densities, and promote the carrier transport induced by the cyano group (C≡N), a rod-like π-conjugated biphenyl mesogenic unit and quaternary alkylammonium cations (R4N+) in 6CNBP-N. Through this functionalized ILC engineering strategy, the power conversion efficiency (PCE) of PSCs is greatly increased from 18.07% for the control PSC to 20.45% for the PSC with 6CNBP-N along with the depressed hysteresis effect and enhanced moisture stability of PSCs. Our work provides a new strategy for designing functionalized additives for high-performance PSCs.

Ripening-resistance of Pd on TiO2(110) from first-principles kinetics.

Suppressing sintering of supported particles is of importance for the study and application of metal-TiO2 system. Theoretical study of Ostwald ripening of TiO2(110)-supported Pd particles would be helpful to extend the understanding of the sintering. In this paper, based on density functional theory (DFT), the surface energy of Pd and the total activation energy (the sum of formation energy and diffusion barrier) of TiO2-supported Pd were calculated. Since the total activation energy is mainly contributed from the formation energy, it is indicated that the ripening of Pd particles would be in the interface control limit. Subsequently, the calculated surface energy and total activation energy were used to simulate Ostwald ripening of TiO2(110)-supported Pd particles. As a result, in comparison with larger particles, smaller particles would worsen the performance of ripening-resistance according to its lower onset temperature and shorter half-life time. The differences on ripening-resistance among different size particles could be mitigated along with the increase of temperature. Moreover, it is verified that the monodispersity can improve ripening resistance especially for the smaller particles. However, the different performances of the ripening originating from difference of the relative standard deviation are more obvious at higher temperature than lower temperature. This temperature effect for the relative standard deviation is the inverse of that for the initial main particle size. It is indicated that the influence of dispersity of TiO2(110)-supported Pd particles on ripening may be more sensitive at higher temperature. In this contribution, we extend the first principle kinetics to elaborate the ripening of Pd on TiO2(110). It is expected that the information from first principle kinetics would be helpful to the study in experiments.

Lithium and Silver Co-Doped Nickel Oxide Hole-Transporting Layer Boosting the Efficiency and Stability of Inverted Planar Perovskite Solar Cells.

In this work, a lithium and silver co-doping strategy has been successfully implied to prepare NiO x films for high performance inverted planar perovskite solar cells (PSCs). Compared to the pristine and single-doped NiO x, the Li and Ag co-doping approach exhibits the synergistic effect and can endow NiO x films with higher electrical conductivity, higher hole mobility and better interface energy band alignment with perovskite active layers. Moreover, the perovskite film with enhanced crystallinity can be obtained induced by the Li,Ag:NiO x film. The PSC with Li,Ag:NiO x HTL shows a high power conversion efficiency (PCE) up to 19.24% and less hysteresis effect, which outperforms the devices with the pristine NiO x or single-doped NiO x HTLs. Meanwhile, the Li,Ag:NiO x device can retain 95% of its initial PCE after storage at the relative humidity of 30 ± 2% in 30 days without encapsulation. Our work demonstrates that lithium and silver co-doping is a promising route for realizing efficient p-type NiO x HTL, which provides a simple way to boost the efficient and stable of inverted planar PSCs.