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Iodine Induced PbI <sub/>2</sub> Porous Morphology Manipulation for High-Performance Planar Perovskite Solar Cells
摘要： The quality of the perovskite film has a vital influence on the performance of perovskite solar cells and it is quite desirable to simultaneously manipulate the crystallization and morphology of the perovskite film. In this study, conventional PbI2 is replaced with a PbI2/I2 mixed precursor during the first step of sequential deposition, causing the formation of a PbI2 porous nanostructure. By changing the content of I2 in the precursor, the morphology of the PbI2 film as well as the resulting perovskite film can be successfully modulated. With an optimal content of I2, a high-quality perovskite film with a pure phase and smooth surface can be achieved. As a result, the conversion efficiency of perovskite solar cells using a PbI2/I2 mixed precursor can be as high as 18.63%, compared to 16.89% for the reference device through traditional sequential deposition with a pure PbI2 precursor.
关键词： porous PbI2,iodine,perovskite,sequential deposition,solar cell
更新于2025-11-20 15:33:11
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Potassium triiodide-quenched gold nanocluster as a fluorescent turn-on probe for sensing cysteine/homocysteine in human serum
摘要： A fluorescent sensing platform using KI3-quenched bovine serum albumin stabilized gold nanoclusters has been designed and used as a fluorescent probe for the turn-on detection of homocysteine/cysteine (Cys/Hcy). The fluorescence of gold nanoclusters was quenched by iodine. The fluorescence of quenched gold nanoclusters was effectively switched on by Cys/Hcy devoid of the interference of glutathione. The transmission electron microscopy image, X-ray photoelectron spectroscopy analysis, time-correlated single photon counting analysis, and dynamic light scattering data confirmed the aggregation-induced quenching of fluorescence of gold nanoclusters by iodine. The turn-on response of Cys/Hcy shows two linear ranges from 0.0057 to 5 μM and from 8 to 25 μM, with a limit of detection of 9 nM for cysteine and 12 nM for homocysteine. Real samples were analyzed to monitor Cys/Hcy added to human serum. The fluorescence turn-on response of the probe on a paper strip in the presence of Cys/Hcy was studied.
关键词： Cysteine,Fluorescence turn on,Gold nanocluster,Bovine serum albumin,Iodine,Homocysteine
更新于2025-09-23 15:22:29
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Frequency shift of an optical frequency standard as a function of probe modulation of the radiation frequency, pressure, and gas temperature in an absorbing cell
摘要： Frequency shifts of an optical Nd : YAG/I2-standard are measured in a pressure range of molecular iodine 5 – 22 mTorr and deviation of probe modulation frequency 480 kHz – 4 MHz for the hyperfine structure component a1 of the molecular iodine absorption line R(56) 32 – 0. The frequency shift of the optical standard is estimated under varied temperatures of a cell and cell finger, which determines the pressure of the molecular iodine vapour. The requirements are defined to temperature stability of the cell and its finger for obtaining high long-term frequency stability of the optical frequency standard.
关键词： molecular iodine,optical frequency standards,saturation absorption spectroscopy,acousto-optical modulator,lasers,luminescence
更新于2025-09-23 15:21:21
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From metallic lead films to perovskite solar cells through lead conversion with polyhalides solutions
摘要： Solutions of methylammonium and formamidinium polyhalides (AX1+n, A = MA, FA, X = I, Br) in isopropanol are introduced as a novel versatile precursor for the fabrication of APbX3 hybrid perovskite thin films via oxidation of metallic Pb. The polyhalides solution with adjustable reactivity is distributed over metallic Pb layer followed by an iodine vapor post-processing to tune the morphology and composition of the film using only the elements inherently present in the perovskite. This method is easily reproducible in any materials science laboratory with an equipment commonly used for perovskite solar cells fabrication and resulted in 16.2% and 17.2% PCE of planar solar cells using MAPbI3 and MA0.25FA0.75PbI2.75Br0.25 perovskites as a proof-of-concept. Implementation of metallic lead thin films as a single Pb-containing precursor reduces a number of in-lab handling hazards compared to classical PbI2 powder and solutions, and provides a variety of scalable deposition options.
关键词： Polyhalides,iodine vapor,metallic lead,perovskite solar cells,perovskite fabrication
更新于2025-09-23 15:21:01
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Iodine Quantification on Spectral Detector-Based Dual-Energy CT Enterography: Correlation with Crohn's Disease Activity Index and External Validation
摘要： Objective: To correlate CT parameters on detector-based dual-energy CT enterography (DECTE) with Crohn’s disease activity index (CDAI) and externally validate quantitative CT parameters. Materials and Methods: Thirty-nine patients with CD were retrospectively enrolled. Two radiologists reviewed DECTE images by consensus for qualitative and quantitative CT features. CT attenuation and iodine concentration for the diseased bowel were also measured. Univariate statistical tests were used to evaluate whether there was a significant difference in CTE features between remission and active groups, on the basis of the CDAI score. Pearson’s correlation test and multiple linear regression analyses were used to assess the correlation between quantitative CT parameters and CDAI. For external validation, an additional 33 consecutive patients were recruited. The correlation and concordance rate were calculated between real and estimated CDAI. Results: There were significant differences between remission and active groups in the bowel enhancement pattern, subjective degree of enhancement, mesenteric fat infiltration, comb sign, and obstruction (p < 0.05). Significant correlations were found between CDAI and quantitative CT parameters, including number of lesions (correlation coefficient, r = 0.573), bowel wall thickness (r = 0.477), iodine concentration (r = 0.744), and relative degree of enhancement (r = 0.541; p < 0.05). Iodine concentration remained the sole independent variable associated with CDAI in multivariate analysis (p = 0.001). The linear regression equation for CDAI (y) and iodine concentration (x) was y = 53.549x + 55.111. For validation patients, a significant correlation (r = 0.925; p < 0.001) and high concordance rate (87.9%, 29/33) were observed between real and estimated CDAIs. Conclusion: Iodine concentration, measured on detector-based DECTE, represents a convenient and reproducible biomarker to monitor disease activity in CD.
关键词： Crohn’s disease,Iodine quantification,Activity index,Dual-energy computed tomography
更新于2025-09-23 15:21:01
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Restricting ?′-phase transformation of HC(NH2)2PbI3via iodine-vacancy filling for efficient perovskite solar cells; ???è?￥?￠???o??????????′-HC(NH2)2PbI3?????￥????¤?é??????¤aé?3??μ?±?;
摘要： Formamidinium lead halide (α-FAPbI3) with a broad light absorption spectrum, has recently received considerable attention in optoelectronic applications. However, the FAI-PbI2-DMSO (DMSO: dimethyl sulfoxide) intermediate anisotropic fibers readily form a non-perovskite phase (δ-FAPbI3) and uncontrolled excess PbI2, which hinders the further increase in the efficiencies of solar cells. Calculations indicate that iodine defects in polycrystalline films would enlarge the perovskite tolerance factor and result in the formation of iodide Frenkel defects. Herein, we introduce a post-treatment technique to heal the as-prepared FAPbI3 thin layer and restrain the notorious δ-FAPbI3 through vacancy filling. Furthermore, a new intermediate phase of FAI-PbI2-DMSO-FACl led to a high-quality perovskite layer with an enlarged average grain size that exceeded 2 μm. Consequently, the power conversion efficiencies of FAPbI3 solar cells were significantly enhanced due to the high crystallity of the pure α-phase perovskite. Therefore, this method can be used to obtain high pure-black perovskite films and efficient solar cells.
关键词： formamidinium perovskite solar cells,iodine vacancy,post-treatment,nonperovskite phase
更新于2025-09-23 15:21:01
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Facile Exchange of Tightly Bonded L-Type Oleylamine and Diphenylphosphine Ligands on Copper Indium Diselenide Nanocrystals Mediated by Molecular Iodine
摘要： Copper indium diselenide (CuInSe2) nanocrystals are a prototypical I-III-VI semiconductor quantum dot material, typically synthesized in oleylamine (OLAm) as a solvent and capping ligand, often with the addition of diphenylphosphine (DPP) to improve the reaction yield. Using 1H NMR spectroscopy, we study the association of OLAm and DPP on CuInSe2 nanocrystals and find that they both behave as tightly bonded L-type ligands. There is no observable desorption of OLAm or DPP when a toluene-d8 dispersion is heated to 100 oC, and no ligand exchange occurs when the nanocrystals are exposed to other L-type species like trioctylphosphine (TOP), or octadecanethiol (ODT), which can bind as either X-type or L-type. Molecular iodine (I2), however, is found to readily displace both OLAm and DPP from the nanocrystal surface and facilitate efficient and complete ligand exchange with either TOP or ODT, and appears to behave as a Lewis Acidic Z-type ligand. We also find that the X-type ligand, stearic acid (StAc), does not bond to the CuInSe2 nanocrystals under any circumstances.
关键词： L-type ligands,molecular iodine,ligand exchange,CuInSe2 nanocrystals,Z-type ligands
更新于2025-09-23 15:21:01
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Tuning electrolyte configuration and composition for fiber-shaped dye-sensitized solar cell with poly(vinylidene fluoride-co-hexafluoropropylene) gel electrolyte
摘要： Efficient energy generation device is desired to couple with soft electronics for driving devices. Due to frequent uses of soft electronics in indoor conditions, flexible fiber-shaped dye-sensitized solar cell (FDSC) is regarded as the most promising energy generation device due to high light-to-electricity conversion maintenance under weak dim light. Using gel electrolyte to assemble FDSC cannot only restrict electrolyte leakage but also improve device flexibility and stability especially under bending conditions. In this study, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) gel electrolyte is used to fabricate FDSC composed of curled TiO2 nanotube/Ti wire photoanode and Pt counter electrode. It is the first time to control gel electrolyte configuration by adding different PVdF-HFP concentrations, and to optimize iodine concentration in electrolyte regarding to redox ability and electrolyte transmittance. Configuration of gel electrolyte is carefully analyzed to define porous layer and concrete layer of polymer for accumulating liquid electrolyte and inhibiting leakage and evaporation. The highest solar-to-electricity conversion efficiency of 6.32% is obtained for FDSC with 9% PVdF-HFP and 0.04 M I2 in electrolyte, due to well-defined cross-linking structure, abundant redox reactions, and high incident-light illumination through electrolyte. Electrochemical impedance spectroscopy and intensity-modulated photocurrent/photovoltage spectroscopy are used to analyze charge-transfer resistance and charge-collection efficiency.
关键词： Iodine,Cross-linking,Poly(vinylidene fluoride-co-hexafluoropropylene),Fiber-shaped dye-sensitized solar cell,Gel electrolyte
更新于2025-09-23 15:19:57
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Investigating Various Permutations of Copper Iodide/FeCu Tandem Materials as Electrodes for Dye-Sensitized Solar Cells with a Natural Dye
摘要： This work presents the synthesis and deposition of CuI and FeCu materials on copper substrates for dye-sensitized solar cell applications. FeCu is a metastable alloy of iron and copper powders and possesses good optical and intrinsic magnetic properties. Coupled with copper iodide as tandem layers, the deposition of these two materials was permutated over a pure copper substrate, characterized and then tested within a solar cell. The cell was sensitized with a natural dye extracted from a local desert plant (Calotropis Gigantea) and operated with an iodine/triiodide electrolyte. The results show that the best layer arrangement was Cu/FeCu/CuI, which gave an efficiency of around 0.763% (compared to 0.196% from reported cells in the literature using a natural sensitizer).
关键词： natural sensitizers,copper iodine,FeCu alloys,dye-sensitized solar cells,Calotropis Gigantea,ball milling
更新于2025-09-23 15:19:57
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Dual-energy CT iodine quantification for characterizing focal thyroid lesions
摘要： Background: To determine the usefulness of dual-energy CT (DECT) iodine quantification to classify the focal thyroid lesions. Methods: We retrospectively enrolled a total of 76 cytopathologically confirmed focal thyroid lesions (mean size: 1.9 cm). After drawing a region of interest on the DECT-derived iodine maps, the obtained iodine concentration values of thyroid nodules (IC_N) and normalized IC_N were compared between 3 groups: papillary thyroid carcinoma (PTC), benign nodule, and cyst. Results: From all lesions, 46, 17, and 13 were assigned to the PTC, benign nodule, and cyst groups. IC_N was the highest in the benign nodule, lower in the PTC, and the lowest (median [interquartile range]: 4.3 [3.13-5.48], 3.15 [2.29-4.01], 0.60 [0.33-0.88], all P < .001). Similarly, the normalized IC_N values were all statistically different from each other (P < .05).The multi-class area under the curves using the optimal cutoff values were 0.931 for IC_N and 0.918, 0.920 for normalized IC, respectively. Conclusion: DECT iodine quantification could be helpful to classify the focal thyroid lesions.
关键词： CT,differential,iodine/analysis,diagnosis,dual-energy,thyroid nodule
更新于2025-09-23 15:19:57