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Metastable Behavior on Cesium Fluoridea??Treated Cu(In <sub/> 1a?? <i>x</i> </sub> ,Ga <sub/><i>x</i> </sub> )Se <sub/>2</sub> Solar Cells
摘要： Metastable behavior of cesium fluoride (CsF)-treated Cu(In1–x,Gax)Se2 (CIGS) solar cells is investigated under heat-light soaking (HLS) and heat-soaking (HS) treatments. HLS increases open-circuit voltage, fill factor, efficiency, and net carrier concentration and decreases short-circuit current density, whereas heat-soaking treatment acts oppositely. The performance of a CsF postdeposition treatment to CIGS thin film in selenium vapor, and closer to stoichiometry copper content, did not mitigate the open-circuit voltage improvement after HLS. These results argue the traditional concept of the VSe–VCu divacancy complex for the total beneficial effect of HLS in alkali-treated CIGS solar cells. The metastable behavior observed in the CsF-treated devices due to the HLS and HS treatments is explained by the specific behavior of alkali-containing new compounds at the surface and/or the migration of alkali metals at the surface and bulk regions.
关键词： heat soaking,heat-light soaking,metastable behavior,high efficiency,CsF-postdeposition treatment
更新于2025-09-23 15:19:57
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Aerial Laser Scanning Data as a Source of Terrain Modeling in a Fluvial Environment: Biasing Factors of Terrain Height Accuracy
摘要： Airborne light detection and ranging (LiDAR) scanning is a commonly used technology for representing the topographic terrain. As LiDAR point clouds include all surface features present in the terrain, one of the key elements for generating a digital terrain model (DTM) is the separation of the ground points. In this study, we intended to reveal the efficiency of different denoising approaches and an easy-to-use ground point classification technique in a floodplain with fluvial forms. We analyzed a point cloud from the perspective of the efficiency of noise reduction, parametrizing a ground point classifier (cloth simulation filter, CSF), interpolation methods and resolutions. Noise filtering resulted a wide range of point numbers in the models, and the number of points had moderate correlation with the mean accuracies (r = ?0.65, p < 0.05), indicating that greater numbers of points had larger errors. The smallest differences belonged to the neighborhood-based noise filtering and the larger cloth size (5) and the smaller threshold value (0.2). The most accurate model was generated with the natural neighbor interpolation with the cloth size of 5 and the threshold of 0.2. These results can serve as a guide for researchers using point clouds when considering the steps of data preparation, classification, or interpolation in a flat terrain.
关键词： cloth simulation filter (CSF),noise filtering,interpolation,floodplain
更新于2025-09-19 17:13:59
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Incorporating CsF into the PbI <sub/>2</sub> Film for Stable Mixed Cation‐Halide Perovskite Solar Cells
摘要： Adding a small amount of CsI into mixed cation-halide perovskite film via a one-step method has been demonstrated as an excellent strategy for high-performance perovskite solar cells (PSCs). However, the one-step method generally relies on an antisolvent washing process, which is hard to control and not suitable for fabricating large-area devices. Here, CsF is employed and Cs is incorporated into perovskite film via a two-step method. It is revealed that CsF can effectively diffuse into the PbI2 seed film, and drastically enhances perovskite crystallization, leading to high-quality Cs-doped perovskite film with a very long photoluminescence carrier lifetime (1413 ns), remarkable light stability, thermal stability, and humidity stability. The fabricated PSCs show power conversion efficiency (PCE) of over 21%, and they are highly thermally stable: in the aging test at 60 °C for 300 h, 96% of the original PCE remains. The CsF incorporation process provides a new avenue for stable high-performance PSCs.
关键词： CsF,mixed cation-halide perovskite solar cells,stability,Cs incorporation
更新于2025-09-11 14:15:04
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Alkali-induced Grain Boundary Reconstruction on Cu(In,Ga)Se2 Thin Film Solar Cells using Cesium Fluoride Post Deposition Treatment
摘要： Heavy alkali metal treatment is a key factor to approach high efficiency in Cu(In, Ga)Se2 (CIGS) solar cells. Here, we show that the Cs-induced surface modification on CIGS thin-film solar cells, especially on grain boundary reconstruction generated from cesium fluoride post-deposition treatment (CsF-PDT). The CsInSe2 phase can be synthesized by CsF-PDT process without extra assistant species, and specifically favors grain boundaries (GBs), which was further characterized by FE-EPMA, TEM, and SIMS analysis. The Cs-contained GBs may both create the valence-band downshift and conduction-band upward. By controlling the Cs-contained layer thickness and modifying absorber, the spike at conduction-band can be overcome by tunneling while remaining high valence-band downshift to suppress the GBs recombination. The efficiency was improved from 15.1 to 18.3% after CsF-PDT; the voltage loss of Eg/q-Voc was down below 0.4 V. Those improvements are mainly contributed from the grain boundary reconstruction at the junction area using CsF-PDT to reduce the recombination.
关键词： PDT,heavy alkali,Voc loss,CIGS,CsF,grain boundary
更新于2025-09-11 14:15:04
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Full-Reference Image Quality Assessment by Combining Features in Spatial and Frequency Domains
摘要： Objective employs mathematical and computational theory to objectively assess the quality of output images based on the human visual system (HVS). In this paper, a novel approach based on multifeature extraction in the spatial and frequency domains is proposed. We combine the gradient magnitude and phase congruency maps to generate a local structure (LS) map, which can perceive local structural distortions. The LS matches well with HVS and highlights differences with details. For complex visual information, such as texture and contrast sensitivity, we deploy the log-Gabor filter, and spatial frequency, respectively, to effectively capture their variations. Moreover, we employ the random forest (RF) to overcome the limitations of existing pooling methods. Compared with support vector regression, RF can obtain better prediction results. Extensive experimental results on the five benchmark databases indicate that the proposed method precedes all the state-of-the-art image quality assessment metrics in terms of prediction accuracy. In addition, the proposed method is in compliance with the subjective evaluations.
关键词： log-Gabor filter,random forest (RF),contrast sensitivity function (CSF),full-reference,Image quality assessment (IQA)
更新于2025-09-09 09:28:46