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Effect of rare earth Pr doping on core characteristics of electrodeposited nanocrystalline Cu2O films: a film for optoelectronic technology
摘要： Undoped and Pr doped Cu2O nanocrystalline ?lms were fabricated by the electrodeposition method. These ?lms were studied to investigate the formation, morphology, optical, and photoresponse properties on Pr doping concentrations (i.e., 0, 1, 3, and 5 wt%). Structural studies of the deposited Cu2O:Pr ?lms exposed the cubic crystal structure with polycrystalline nature. The crystallite size is decreased from 54 to 29 nm by increasing the Pr doping concentrations. The Raman peaks at 110, 147, 215, 413, and 633 con?rm the Cu2O phase and well matched with the XRD results. The morphological study shows that the pyramid-shaped particles are homogeneously arranged on the ?lm surfaces. The absorption is high for the ?lm deposited with the 5% Pr doping is due to the maximum thickness than the other ?lms. The calculated band gap values of Cu2O:Pr ?lms were reduced from 2.06 to 1.90 eV with raising the Pr doping level. PL spectra showed high intense emission peak at 617 nm which con?rms the NBE emission of Cu2O lattice. Index of refraction (n) and coef?cient of extinction (k) values were increased on increasing the doping concentration from 0 to 5%. From photosensitivity analysis, there is an increase of photoresponse behavior with respect to illuminated current.
关键词： Electrodeposition,Structural,Optical and electrical properties,Morphological
更新于2025-11-21 11:18:25
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Maze-Like Halide Perovskite Films for Efficient Electron Transport Layer-Free Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) without an electron transport layer (ETL) exhibit fascinating advantages such as simplified configuration, low cost, and facile fabrication process. However, the performance of ETL-free PSCs has been hampered by severe charge carrier recombination induced either by current leakage (insufficient perovskite film coverage) or inferior charge extraction. Herein, an additive-assisted morphological engineering strategy is used to construct an intriguing bilayer perovskite film featuring a dense bottom layer and a maze-like top layer. Such maze-like perovskite films enable the construction of ETL-free PSCs with a PCE of 18.5% and negligible hysteresis, which can be attributed to the higher crystallinity and superior light-harvesting capability of the resultant perovskite film, as well as facilitated hole extraction at the hole transport layer (HTL)/perovskite interface. This work provides a simple approach to modify the perovskite film morphology and demonstrates the correlation between facilitated charge-carrier extraction and high-performance ETL-free perovskite photovoltaics.
关键词： light harvesting,morphological engineering,additives,perovskite solar cells,charge extraction
更新于2025-10-22 19:40:53
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Synthesis of Bi <sub/>2</sub> O <sub/>3</sub> films, studying their optical, structural, and surface roughness properties
摘要： Reactive pulse laser deposition system was used to prepare Bi2O3 thin films at different laser fluence. It effect on the physical properties of thin films was investigated. A Polymorphous structure was obtaining from XRD results. While the obtained microscopic results from AFM show that grain size is varied between 33.48nm and 131.6 nm. The estimated band gap value from the optical transmission found to range from 1.7-2.9 eV.
关键词： Pulsed laser deposition,morphological properties,Optical properties,Bismuth trioxide,structural properties
更新于2025-09-23 15:23:52
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Effects of the Electrode Modification Conditions on the Performance of Three-state Electrochromic Devices via Spin- coating
摘要： Electrodeposition-based electrochromic devices capture numerous attentions due to their simple sandwich-type structure, facile and low-cost fabrication, and promising application. Herein, titanium dioxide (TiO2) nanoparticles were modified onto fluorine doped tin oxide (FTO) electrode via spin-coating technique with different rotation speed and precursor solution concentration, followed by sandwiching a suitable amount of gel electrolyte between the modified FTO electrode and a flat FTO electrode to fabricate the electrodeposition-based electrochromic device with reversible three-state optical transformation (transparent, mirror and black). A systematic study of correlation between electrode modification condition and morphological features of TiO2 thin films, as well as the performance of electrochromic devices, i.e. optical contrast, switching time, and cycling stability, were investigated. Optimized performances of three-stated electrochromic device could be obtained by properly manipulating the electrode modification conditions. The results in this study will provide valuable guidance for rational design of electrochromic device with satisfactory performance.
关键词： Morphological Features,Rotation Speed,Electrochromic Properties,Precursor Solution Concentration,Spin-coating,Electrochromic
更新于2025-09-23 15:23:52
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Development of a novel noninvasive system for measurement and imaging of the arterial phase oxygen density ratio in the retinal microcirculation
摘要： Purpose This study was conducted in order to develop a novel noninvasive system for measurement and imaging of the arterial oxygen density ratio (ODR) in the retinal microcirculation. Methods We developed a system composed of two digital cameras with two different filters, which were attached to a fundus camera capable of simultaneously obtaining two images. Actual measurements were performed on healthy volunteer eyes (n = 61). A new algorithm for ODR measurement and pixel-level imaging of erythrocytes was constructed from these data. The algorithm was based on the morphological closing operation and the line convergence index filter. For system calibration, we compared and verified the ODR values in arterioles and venules that were specified in advance for 56 eyes with reproducibility. In 10 additional volunteers, ODR measurements and imaging of the arterial phase in the retinal microcirculation corresponding to changes in oxygen saturation of the peripheral arteries at normal breathing and breath holding were performed. Results Estimation of incident light to erythrocytes and pixel-level ODR calculation were achieved using the algorithm. The mean ODR values of arterioles and venules were 0.77 ± 0.060 and 1.02 ± 0.067, respectively. It was possible to separate these regions, calibrate at the pixel level, and estimate the arterial phase. In each of the 10 volunteers, changes in the arterial phase ODR corresponding to changes in oxygen saturation of the peripheral arteries were observed before and after breath holding on ODR images. The mean ODR in 10 volunteers was increased by breath holding (p < 0.05). Conclusions We developed a basic system for arterial phase ODR measurement and imaging of the retinal microcirculation. With further validation and development, this may provide a useful tool for evaluating retinal oxygen metabolism in the retinal microcirculation.
关键词： Retinal microcirculation region,Arterial phase,Line convergence index filter,Oxygen density ratio,Morphological closing operation
更新于2025-09-23 15:23:52
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Breast tumor classification using different features of quantitative ultrasound parametric images
摘要： Rationale and objectives The ultrasound B-mode-based morphological and texture analysis and Nakagami parametric imaging have been proposed to characterize breast tumors. Since these three feature categories of ultrasonic tissue characterization supply information on different physical characteristics of breast tumors, by combining the above methods is expected to provide more clues for classifying breast tumors. Materials and methods To verify the validity of the concept, raw data were obtained from 160 clinical cases. Six different types of morphological-feature parameters, four texture features, and the Nakagami parameter of benignancy and malignancy were extracted for evaluation. The Pearson’s correlation matrix was used to calculate the correlation between different feature parameters. The fuzzy c-means clustering and stepwise regression techniques were utilized to determine the optimal feature set, respectively. The logistic regression, receiver operating characteristic curve, and support vector machine were used to estimate the diagnostic ability. Results The best performance was obtained by combining morphological-feature parameter (e.g., standard deviation of the shortest distance), texture feature (e.g., variance), and the Nakagami parameter, with an accuracy of 89.4%, a specificity of 86.3%, a sensitivity of 92.5%, and an area under receiver operating characteristic curve of 0.96. There was no significant difference between using fuzzy c-means clustering, logistic regression, and support vector machine based on the optimal feature set for breast tumors classification. Conclusion Therefore, we verified that different physical ultrasonic features are functionally complementary and thus improve the performance in diagnosing breast tumors. Moreover, the optimal feature set had the maximum discriminating performance should be irrelative to the power of classifiers.
关键词： Morphological features,Breast ultrasound,Nakagami parameter,Texture features,Classification
更新于2025-09-23 15:23:52
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Enhanced upconversion luminescence intensity of core-shell NaYF4 nanocrystals guided by morphological control
摘要： How to further increase the upconversion luminescence (UCL) efficiency of core-shell upconversion nanoparticles (UCNPs) is highly desirable for their photoelectric and biological applications. Herein, a novel but facile strategy is proposed to substantially enhance the UCL intensity of NaYF4 based core-shell UCNPs by morphological control. The morphologies of core-shell UCNPs can be optimized from rod-like to spherical like by changing the ratio of oleic acid (OA) to 1-octadecene (ODE) during the shell growth process with other reaction conditions constant. The mechanism of shape control is further investigated based on the competitive absorption between OA molecules and lanthanide ions (Y3+, Yb3+, Er3+ or Tm3+) onto the different crystal axes (a, b and c) to guide their shell growth speed. The absolute quantum yields were up to 2.7 % and 1.8 % for spherical and rod like core-shell UCNPs under excitation of 980 nm laser (power density of 1.6 W/cm2), respectively. Moreover, the UCL intensity and effective lifetime (τeff) of Er3+ emission at 541 nm of spherical like core-shell UCNPs increased by 11.7 and 1.82 folds than rod like core-shell UCNPs. Therefore, our designed novel strategy can greatly improve the UCL efficiency of core-shell UCNPs and promote their development in diverse applications.
关键词： upconversion nanoparticles,upconversion luminescence,core-shell structure,morphological control
更新于2025-09-23 15:23:52
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Morphological regulation of all-inorganic perovskites for multilevel resistive switching
摘要： Enormous attention has been paid to all-inorganic cesium lead halide perovskites in various photoelectronic fields for their remarkable performances. However, comparing to their analogue organic-inorganic hybrid perovskites, the film morphology of such all-inorganic lead halide perovskites is difficult to control due to the low solubility of cesium salt. Here, we propose a new fabrication routine to control the film morphology of CsPbBr3. A series of CsPbBr3 thin films with big grains (≈800 nm) were successfully prepared. The memristors based on such CsPbBr3 thin films take on typical bipolar resistive switching behavior and remarkable characteristics such as high Ron/Roff ratio (≈105), very low working voltage (≈ ± 1 V), and long data retention (≥104 s). Furthermore, through modulating the film morphology, memristors with multilevel resistive switching behavior can be easily prepared. These advantages demonstrate that the all-inorganic cesium lead halide memristors possess great potential for future application.
关键词： Memristor,Morphological regulation,Multilevel resistive switching,All-inorganic perovskite
更新于2025-09-23 15:23:52
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Light-induced effects on crystal size and photo-stability of colloidal CsPbBr<sub>3</sub> perovskite nanocrystals
摘要： CsPbBr3 perovskite nanocrystals (PNCs) have been synthesized using the hot injection method. The CsPbBr3 PNCs exhibit a high photoluminescence quantum yield (PLQY) of 73%. A comprehensive study of UV light interaction with the CsPbBr3 PNCs was performed. SEM images, photoluminescence spectra, X-Ray Diffraction and PLQY measurements were obtained for different time of UV exposure. The exposure to UV light modifies the crystal size (from 10X10 nm to 12X95 nm) and morphology (change from nanocubic to nanorods form). The XRD spectra show a change from tetragonal to cubic crystalline structure. In addition, the interaction of UV light modifies the optical properties of the PNCs by varying the photoluminescence. The material remains stable for a period of 1 hour, however, with exposure to UV light, the PNCs show a decrement in QY from 73.3% to 46.6% after 30 days. These results indicate that light-induce variation in morphological and photo-stability of CsPbBr3 PNCs.
关键词： luminescence,photostability,CsPbBr3 nanocrystals,morphological study
更新于2025-09-23 15:23:52
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Evaluation of ForestPA for VHR RS image classification using spectral and superpixel-guided morphological profiles
摘要： In very high resolution (VHR) remote sensing (RS) classification tasks, conventional pixel-based contextual information extraction methods such as morphological profiles (MPs), extended MPs (EMPs) and MPs with partial reconstruction (MPPR) with limited numbers, sizes and shapes of structural elements (SEs) cannot perfectly match all sizes and shapes of the objects in an image. To overcome such limitation, we introduce novel spatial feature extractors, namely, the superpixel-guided morphological profiles (SPMPs), where the superpixels are used as SEs in opening by reconstruction and closing by reconstruction operations. Moreover, to avoid possible side effects from unusual maximum and minimum values within superpixels, the mean pixel value of superpixels is adopted (SPMPsM). Additionally, new decision forest based on penalizing the attributes in previous trees, the ForestPA is introduced and evaluated through a comparative investigation on three VHR multi-/hyperspectral RS image classification tasks. Support vector machine and benchmark ensemble classifiers, including bagging, AdaBoost, MultiBoost, ExtraTrees, Random Forest and Rotation Forest, are adopted. The experimental results confirm the effectiveness and superior performances of the proposed SPMPs and SPMPsM relative to those of the MPs and MPPR. Moreover, ForestPA outperforms only bagging and is not suitable for learning from large numbers of samples with high dimensionality from the computational efficiency and classification accuracy perspective.
关键词： ForestPA,superpixel,MPs,superpixel-guided morphological profiles,MPPR,image classification,VHR images
更新于2025-09-23 15:23:52