Synthesis of poly(3,4-propylenedioxythiophene)/MnO2 composites and their applications in the adsorptive removal of methylene blue

AbstractThe poly(3,4-propylenedioxythiophene)/MnO2 composites (PProDOT/MnO2) were prepared successfully by soaking the PProDOT powders into potassium permanganate (KMnO4) solution, with the mass ratio of PProDOT and KMnO4 from 2:1 to 1:2. The structure and morphology of composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet–visible absorption spectra (UV), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscope (FE-SEM). Furthermore, PProDOT/MnO2 composites were tested as the adsorbents for removal of methylene blue (MB) from aqueous solution. The results revealed that the composites were successfully synthesized, and the thiophene sulfur was oxidized into sulfoxide by KMnO4. The highest percentage removal of MB after 30min was 91% for PProDOT/MnO2 (1:2) composite, and the percentage removal of MB was ~12mgg−1 after 60min at initial concentrations of MB dye of 5.6mgL−1 in the case of PProDOT/MnO2 (1:2) composite. Besides, the adsorption process of PProDOT/MnO2 (1:2) composite was described by pseudo-second-order and Langmuir models

Clinical Value of Spectral Imaging Combined with MAR for CTA after Embolization of Intracranial Aneurysms

Objective: To evaluate the application value of combining spectral imaging and metal artifact reduction (MAR) in head and neck CTA after the embolization of intracranial aneurysms. Methods: We collected 37 patients who experienced embolization of intracranial aneurysms then received spectral imaging of head and neck CTA. Monochromatic images with energy ranging from 70～140 keV, 120 kVp-like mixed energic images, 70～140 keV MAR images, and 120 kVp-like MAR images were generated. The region of interest was placed on the area near the coil and with the most serious metal artifact. CT attenuation and standard deviation were measured, and artifact index (AI) and signal-noise ratio (SNR) were calculated. Two radiologists independently subjectively evaluated the metal artifact and the display of surrounding vessels using Likert 5 scales. The subjective scores and objective parameters between MAR and non-MAR images were compared. The Wilcoxon ranking test, paired sample t test, and independent sample t test were utilized to compare parameters between the groups. Results: MAR images had significantly lower AI than did non-MAR images for all eight monochromatic energies. When energies ranged from 80~110 keV, SNR was higher for MAR images than for non-MAR images, and the difference was statistically significant. With same energies, MAR images had higher artifact and vessel display scores than did non-MAR images. For non-MAR images, the different coil diameters did not make a statistical difference in AI and vessel display scores. For MAR images, a larger coil diameter (>8.79 mm) led to higher AI and lower vessel display scores than did normal diameters (≤8.79 mm). Conclusion: The combination of spectral imaging and MAR could effectively reduce the metal artifact of implants for the embolization of intracranial aneurysms and improve the surrounding vessel display. Moreover, the metal artifact reduction effect was more significant for the coils with smaller diameters

Unveiling the additive-assisted oriented growth of perovskite crystallite for high performance light-emitting diodes.

Solution-processed metal halide perovskites have been recognized as one of the most promising semiconductors, with applications in light-emitting diodes (LEDs), solar cells and lasers. Various additives have been widely used in perovskite precursor solutions, aiming to improve the formed perovskite film quality through passivating defects and controlling the crystallinity. The additive's role of defect passivation has been intensively investigated, while a deep understanding of how additives influence the crystallization process of perovskites is lacking. Here, we reveal a general additive-assisted crystal formation pathway for FAPbI3 perovskite with vertical orientation, by tracking the chemical interaction in the precursor solution and crystallographic evolution during the film formation process. The resulting understanding motivates us to use a new additive with multi-functional groups, 2-(2-(2-Aminoethoxy)ethoxy)acetic acid, which can facilitate the orientated growth of perovskite and passivate defects, leading to perovskite layer with high crystallinity and low defect density and thereby record-high performance NIR perovskite LEDs (~800 nm emission peak, a peak external quantum efficiency of 22.2% with enhanced stability)

Efficient and bright warm-white electroluminescence from lead-free metal halides.

Solution-processed metal-halide perovskites are emerging as one of the most promising materials for displays, lighting and energy generation. Currently, the best-performing perovskite optoelectronic devices are based on lead halides and the lead toxicity severely restricts their practical applications. Moreover, efficient white electroluminescence from broadband-emission metal halides remains a challenge. Here we demonstrate efficient and bright lead-free LEDs based on cesium copper halides enabled by introducing an organic additive (Tween, polyethylene glycol sorbitan monooleate) into the precursor solutions. We find the additive can reduce the trap states, enhancing the photoluminescence quantum efficiency of the metal halide films, and increase the surface potential, facilitating the hole injection and transport in the LEDs. Consequently, we achieve warm-white LEDs reaching an external quantum efficiency of 3.1% and a luminance of 1570 cd m-2 at a low voltage of 5.4 V, showing great promise of lead-free metal halides for solution-processed white LED applications

Revealing the crystalline packing structure of Y6 in the active layer of organic solar cells: the critical role of solvent additives

The bulk heterojunction (BHJ) morphology of photovoltaic materials is crucial to the fundamental optoelectronic properties of organic solar cells (OSCs). However, in the photoactive layer, the intrinsic crystalline packing structure of Y6, currently the hallmark molecule among Y-series non-fullerene acceptors (NFAs), has not been unambiguously determined. Here, employing grazing-incidence wide-angle X-ray scattering (GIWAXS), we managed to uncover the intrinsic crystalline packing structure of Y6 in the BHJ active layer of OSCs, which is found to be different from its single-crystal structure reported previously. Moreover, we find that solvent additive 1-chloronaphthalene (CN) can induce highly ordered packing of Y6 in BHJ thin films. With the help of atomistic molecular dynamics simulations, it is revealed that π-π interactions generally exist between naphthalene derivatives and IC terminals of Y6 analogues, which would essentially improve their long-range ordering. Our work reveals the intrinsic crystalline packing structure of Y6 in the BHJ active layer as well as its crystallization mechanism in thin films, thus providing direct correlations between this crystalline packing and the device characteristics and photophysical properties.Knut och Alice Wallenbergs StiftelseImmediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Critical Influence of Organic A′-Site Ligand Structure on 2D Perovskite Crystallization

Organic A′-site ligand structure plays a crucial role in the crystal growth of 2D perovskites, but the underlying mechanism has not been adequately understood. This problem is tackled by studying the influence of two isomeric A′-site ligands, linear-shaped n-butylammonium (n-BA+) and branched iso-butylammonium (iso-BA+), on 2D perovskites from precursor to device, with a combination of in situ grazing-incidence wide-angle X-ray scattering and density functional theory. It is found that branched iso-BA+, due to the lower aggregation enthalpies, tends to form large-size clusters in the precursor solution, which can act as pre-nucleation sites to expedite the crystallization of vertically oriented 2D perovskites. Furthermore, iso-BA+ is less likely to be incorporated into the MAPbI3 lattice than n-BA+, suppressing the formation of unwanted multi-oriented perovskites. These findings well explain the better device performance of 2D perovskite solar cells based on iso-BA+ and elucidate the fundamental mechanism of ligand structural impact on 2D perovskite crystallization

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