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Performance Enhancement of Dye-Sensitized Solar Cells by Utilizing Carbon Nanotubes as an Electrolyte Treating Agent
摘要： A new carbon nanotube (CNT) function is proposed herein for dye-sensitized solar cell (DSSC) applications. In this study, single-wall CNT is used as a treating agent to the conventional liquid electrolytes, which differs from the role of a gelator or an additive as reported in the literature. The experimental results show that the electrochemical properties of the electrolytes do not alter significantly after the CNT treatment; however, the conversion efficiencies of the DSSCs are evidently improved (from 8.15% to 8.70%), which is attributed mainly to the enhanced open-circuit voltages. Device characterizations indicate that the higher voltages are due to the suppression of charge recombination at the TiO2/electrolyte interface. Furthermore, based on the Raman and UV-Vis spectra of the electrolytes, the concentrations of triiodide and higher polyiodide species are reduced after the CNT treatment. The Raman and XPS spectral results further verify the adsorption of polyiodides on the CNTs. More importantly, because fewer polyiodides are present in the electrolyte, fewer electrons in the TiO2 can be recombined; therefore, higher voltages are achieved for the corresponding cells. Quasi-solid-state DSSCs fabricated using CNT-treated electrolytes also demonstrate better cell performance. This CNT effect is anticipated to facilitate the progress of DSSCs.
关键词： centrifugation,iodine,printable,impedance spectroscopy,redox couple
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Iodine-Stabilized 633 nm Diode Lasers for Metrology and Interferometry
摘要： Helium-neon lasers at 633 nm are still widely used in interferometers and, stabilized to iodine, serve as secondary frequency standards for the practical realisation of the meter [1]. However, the technical know-how for building and maintaining helium-neon laser tubes is slowly disappearing. Diode lasers are an attractive alternative with respect to availability, cost, output power, size and power consumption. The emission wavelength of 633 nm allows new systems to be easily integrated into existing setups. For replacing the helium-neon laser and enhancing the stability and accuracy, we have investigated an extended-cavity diode laser (ECDL) stabilized on an external cavity containing an iodine cell using Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS) at 633 nm. The cavity provides a well-defined, long-term stable geometry, resulting in a robust system. In addition, the increased intra-cavity power and the increased effective absorption length result in absorption signals with high signal-to-noise ratio [2]. NICE-OHMS has been widely used for ultra-sensitive detection of molecular absorption lines [3]. However, for laser stabilization it has only been applied in the infrared regime so far [4,5]. Fig. 1 shows the Allan deviations of a diode laser stabilized to iodine using NICE-OHMS (red) compared to a PTB iodine-stabilized helium-neon laser (black). The diode laser reaches a frequency instability of 3.2(cid:117)10-12 at 1 s, which is lower than for the helium-neon laser (4.1(cid:117)10-12 at 1 s), while the instability of the diode laser starts to rise at averaging times longer than 100 s. Using a NICE-OHMS stabilized diode laser at 633 nm, we have – to the best of our knowledge – reached for the first time a short time frequency instability below that of a state-of-the-art iodine stabilized helium-neon laser. This system has good prospects to serve as a frequency standard at 633 nm. To reach this goal, further investigations of the long-term instability, of the reproducibility and of the sensitivities of the absolute frequency on various parameters are underway.
关键词： Interferometry,Iodine-Stabilized,Metrology,633 nm Diode Lasers,NICE-OHMS
更新于2025-09-12 10:27:22
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Chemical inhibition of reversible decomposition for efficient and super-stable perovskite solar cells
摘要： Despite the remarkable photovoltaic characteristics and printability of perovskite solar cells, their intrinsic instability has been the most serious drawback toward future commercialization. In this work, we have investigated the stability of perovskite films in terms of morphology, electronic properties and chemical compositions. Specifically, the chemical decomposition inhibition strategy was introduced in perovskite films through iodine bromide to modify the crystal defects, leading to PSCs with suppressed hysteresis effects, superior durability and attractive PCE of 21.5%. Femto-second transient absorption spectra and GIWAXS measurements provide deep insight into the reduced carrier recombination and indicate the improved crystallinity of the modified perovskite films. Furthermore, an efficient hole-transporting material, PDPP4T, without using any doping process is applied to achieve PSCs with enhanced open-circuit voltage and better repeatability. As a consequence, the modified PSCs could maintain 82% of their initial efficiency after 5000 h of storage in ambient conditions and 90% of their initial efficiency after 1000 h of light soaking process. An excellent water resistance up to 100 h of the PSCs is also obtained by encapsulation technology. Besides, after coating Ce3+-CsPbI3 nanocrystals as luminescent down-shifting layers on the front side of the PSCs, the PCE of the device was further improved to 22.16 %.
关键词： iodine bromide,stability,perovskite solar cells,chemical inhibition,decomposition
更新于2025-09-11 14:15:04
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Incorporation of Nickel Ions to Enhance Integrity and Stability of Perovskite Crystal Lattice for High-Performance Planar Heterojunction Solar Cells
摘要： Enhancement of integrity and stability of crystal lattice are highly challenging for poly-crystalline perovskite films. In this work, a nickel (Ni) ions incorporation strategy is presented to modulate the crystal structure of CH3NH3PbI3 perovskite film. A broad range of experimental characterizations reveal that the incorporation of Ni ions can substantially eliminate the intrinsic halide vacancy defects since Ni ions have a strong preference for octahedral coordination with halide ions, resulting in improved integrity and short-range order of crystal lattice significantly. Moreover, it is also demonstrated that the stronger chemical bonding interaction between Ni ions and halide ions as well as organic group can improve the stability of perovskite material. Simultaneously, the surface morphology of perovskite thin film is also improved by incorporation of nickel ions. As a result, the 1.5% Ni-incorporated planar heterojunction perovskite solar cell exhibits a power conversion efficiency of 18.82%, which is improved by 25% compared with 14.92% for the pristine device. Simultaneously, the 1.5% Ni- incorporated device shows remarkable stability with 90% of the initial efficiency after storage in air environment for 800 h. The studies provide a new insight for metal-incorporated perovskite materials for various optoelectronic applications.
关键词： Ni ions,crystal lattice,Perovskite Solar Cells,MAPbI3,iodine vacancy defects
更新于2025-09-11 14:15:04
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[IEEE 2019 Joint Conference of the IEEE International Frequency Control Symposium anEuropean Frequency and Time Forum (EFTF/IFC) - Orlando, FL, USA (2019.4.14-2019.4.18)] 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC) - Iodine-Stabilized 633 nm Diode Lasers for Metrology and Interferometry
摘要： For interferometric length measurements and other metrology applications 633 nm helium-neon lasers are still widely used. Here we present two 633 nm diode laser systems stabilized to iodine that can replace this old technique: a compact and robust system based on Doppler-broadened spectroscopy with uncertainty <10-8 for interferometric length measurements and a high-end system with instability below 10-11 based on saturated absorption using the NICE-OHMS method for realization of an optical frequency standard.
关键词： iodine,frequency standard,diode laser,NICE-OHMS,633 nm
更新于2025-09-11 14:15:04
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Differentiation of Hemorrhage from Iodine Using Spectral Detector CT: A Phantom Study
摘要： BACKGROUND AND PURPOSE: Conventional CT often cannot distinguish hemorrhage from iodine extravasation following reperfusion therapy for acute ischemic stroke. We investigated the potential of spectral detector CT in differentiating these lesions. MATERIALS AND METHODS: Centrifuged blood with increasing hematocrit (5%– 85%) was used to model hemorrhage. Pure blood, blood-iodine mixtures (75/25, 50/50, and 25/75 ratios), and iodine solutions (0 –14 mg I/mL) were scanned in a phantom with attenuation ranging from 12 to 75 HU on conventional imaging. Conventional and virtual noncontrast attenuation was compared and investigated for correlation with calculation of relative virtual noncontrast attenuation. Values for all investigated categories were compared using the Mann-Whitney U test. Sensitivity and speci?city of virtual noncontrast, relative virtual noncontrast, conventional CT attenuation, and iodine quanti?cation for hemorrhage detection were determined with receiver operating characteristic analysis. RESULTS: Conventional image attenuation was not signi?cantly different among all samples containing blood (P (cid:2) .05), while virtual noncontrast attenuation showed a signi?cant decrease with a decreasing blood component (P (cid:3) .01) in all blood-iodine mixtures. Relative virtual noncontrast values were signi?cantly different among all investigated categories (P (cid:3) .01), with correct hemorrhagic component size estimation for all categories within a 95% con?dence interval. Areas under the curve for hemorrhage detection were 0.97, 0.87, 0.29, and 0.16 for virtual noncontrast, relative virtual noncontrast, conventional CT attenuation, and iodine quanti?cation, respectively. A (cid:2)10-HU virtual noncontrast, (cid:2)20-HU virtual noncontrast, (cid:2)40% relative virtual noncontrast, and combined (cid:2)10-HU virtual noncontrast and (cid:2)40% relative virtual noncontrast attenuation threshold had a sensitivity/speci?city for detecting hemorrhage of 100%/23%, 89%/95%, 100%/82%, and 100%/100%, respectively. CONCLUSIONS: Spectral detector CT can accurately differentiate blood from iodinated contrast in a phantom setting.
关键词： hemorrhage,phantom study,spectral detector CT,iodine,differentiation
更新于2025-09-10 09:29:36
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Incarceration of iodine in a pyrene-based metal-organic framework
摘要： A pyrene-based metal–organic framework (MOF) SION-8 captures iodine (I2) vapour with a capacity of 460 mg g–1 MOF and 250 mg g–1 MOF at room temperature and at 75 °C, respectively. Single-crystal X-ray diffraction analysis and van der Waals-corrected density functional theory calculations confirm the presence of I2 molecules within the pores of SION-8 and their interaction with the pyrene-based ligands. The I2-pyrene interactions in the I2-loaded SION-8 lead to a 104-fold increase of its electrical conductivity compared to the bare SION-8. Upon adsorption, ≥95% of I2 molecules are incarcerated and cannot be washed out, signifying the potential of SION-8 towards the permanent capture of radioactive I2 at room temperature.
关键词： charge transfer,conductivity,impedance spectroscopy,iodine capture,metal–organic framework
更新于2025-09-10 09:29:36
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Detection of gastric cancer and its histological type based on iodine concentration in spectral CT
摘要： Background: Computed tomography (CT) imaging is the most common imaging modality for the diagnosis and staging of gastric cancer. The aim of this study is was to prospectively explore the ability of quantitative spectral CT parameters in the detection of gastric cancer and its histologic types. Methods: A total of 87 gastric adenocarcinoma (43 poorly and 44 well-differentiated) patients and 36 patients with benign gastric wall lesions (25 inflammation and 11 normal), who underwent dual-phase enhanced spectral CT examination, were retrospectively enrolled in this study. Iodine concentration (IC) and normalized iodine concentration (nIC) during arterial phase (AP) and portal venous phase (PP) were measured thrice in each patient by two blinded radiologists. Moreover, intraclass correlation coefficient (ICC) was used to assess the interobserver reproducibility. Differences of IC and nIC values between gastric cancer and benign lesion groups were compared using Mann-Whitney U test. Furthermore, the gender, age, location, thickness and histological types of gastric adenocarcinoma were analyzed by Mann-Whitney U test or Kruskal-Wallis H test. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of IC and nIC values, and the optimal cut-off value was calculated with Youden J. Results: An excellent interobserver agreement (ICC > 0.6) was achieved for IC. Notably, the values of ICAP, ICPP, nICAP and nICPP were significantly higher in gastric cancer group (Z = 5.870, 3.894, 2.009 and 10.137, respectively; P < 0.05) than those in benign lesion group. Additionally, the values of ICAP, ICPP, nICAP and nICPP were significantly higher in poorly differentiated gastric adenocarcinoma group (Z = 4.118, 5.637, 6.729 and 2.950, respectively; P < 0.005) than those in well-differentiated gastric adenocarcinoma group. There were no statistically significant differences in the values of ICAP, ICPP, nICAP and nICPP between age, gender, tumor thickness and tumor location. Furthermore, the area under the curve (AUC) values of ICAP, nICAP, ICPP and nICPP were 0.745, 0.584, 0.662, and 0.932, respectively, for gastric cancer detection; while 0.756, 0.919, 0.851 and 0.684, respectively, in discriminating poorly differentiated gastric adenocarcinoma. Conclusion: IC values exhibited great potential in the preoperative and non-invasive diagnosis of gastric cancer and its histological types. In particular, nICPP is more effective for the identification of gastric cancer, whereas nICAP is more effective in discriminating poorly differentiated gastric adenocarcinoma.
关键词： Adenocarcinoma,Gastric,Iodine concentration,Histological degree,Spectral CT imaging
更新于2025-09-10 09:29:36
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Influence of Iodine Doping on the Structure, Morphology and Physical Properties of Manganese Phthalocyanine Thin Films
摘要： Doping with halide ions is a popular method to alter the properties of metal phthalocyanines (MPcs), particularly magnetic and electrical nature of organic semiconductors for applications in spintronic or electronic devices. Doping can cause a structural rearrangement in MPc packing and the physical properties may be correlated with molecular packing. Films of a planar and magnetic MPc, manganese(II)phthalocyanine (MnPc) is chosen for iodine doping study. The optical, magnetic and the electrical properties of pristine and iodine doped MnPc thin films are investigated and can be directly associated with their molecular structure. 2D grazing incidence Synchrotron X-ray diffraction reveals structural disorder in MnPc films upon iodine infusion induced by the reorientation of ordered, edge-on molecular configuration to tilted and face-on configurations in a random fashion. The film morphology changes accordingly, where in the uniform crystallites reorganize in a disordered manner. The ferromagnetic nature of the pristine film gets weakened due to iodine species and favors antiferromagnetic coupling. The study of electrical properties at room temperature by conducting atomic force microscopy reveals that the conductance is enhanced independently of the film thickness due to disorder induced by iodine inclusion.
关键词： Thin Films,Electrical properties,Structural rearrangement,Manganese Phthalocyanine,Iodine doping,Magnetic properties
更新于2025-09-09 09:28:46
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Dual Energy Spectral CT Imaging in the assessment of Gastric Cancer and cell proliferation: A Preliminary Study
摘要： Gastric cancer is one of the main diseases leading to cancer-related death. The recently introduced dual-energy spectral CT (DEsCT), allows to obtain many quantitative measurements from iodine-based material decomposition (MD) images, which contribute to improve the accuracy of staging of GC comparing to multidetector spiral CT. And Ki-67 is a well-recognized nuclear antigen-specific biomarker reflecting cellular proliferation for estimating growth fractions of various tumor types. In the present study we analyzed the features of quantitative measurements (the curve slope (λHU), IC, normalized iodine concentrations (NIC)) obtained from DEsCT and levels of Ki-67 protein expression. We demonstrated that the values between advanced gastric cancer (AGC) and early gastric cancer (EGC) were significantly different both in venous phase (VP) and delayed phase (DP). The values of different level of Ki-67 expression grade were significantly different both in VP and DP. The rank correlation analysis between Ki-67 grade and IC, NIC and λHU values showed significantly positive correlation in VP and DP. These results suggested that quantitative parameters (IC, NIC and λHU) in dual-energy CT imaging can be used to differentiate EGC from AGC, and have significantly positive correlation with Ki-67 antigen expression levels in gastric cancer for indicating tumor cellular proliferation.
关键词： Gastric cancer,dual-energy spectral CT,Ki-67,iodine concentration,cellular proliferation
更新于2025-09-09 09:28:46