Chemically doped poly2,5-bis(3-alkylthiophen-2-yl)thieno3,2-bthiophene (PBTTT) shows promise for many organic electronic applications, but rationalizing its charge transport properties is ...challenging because conjugated polymers are inhomogeneous, with convoluted optical and solid-state transport properties. Herein, we use the semilocalized transport (SLoT) model to quantify how the charge transport properties of PBTTT change as a function of iron(III) chloride (FeCl3) doping level. We use the SLoT model to calculate fundamental transport parameters, including the carrier density needed for metal-like electrical conductivities and the position of the Fermi energy level with respect to the transport edge. We then contextualize these parameters with other polymer-dopant systems and previous PBTTT reports. Additionally, we use grazing incidence wide-angle X-ray scattering and spectroscopic ellipsometry techniques to better characterize inhomogeneity in PBTTT. Our analyses indicate that PBTTT obtains high electrical conductivities due to its quickly rising reduced Fermi energy level, and this rise is afforded by its locally high carrier densities in highly ordered microdomains. Ultimately, this report sets a benchmark for comparing transport properties across polymer-dopant-processing systems.
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This study investigates the solid-state charge transport properties of the oxidized forms of dioxythiophene-based alternating copolymers consisting of an oligoether-functionalized ...3,4-propylenedioxythiophene (ProDOT) copolymerized with different aryl groups, dimethyl ProDOT (DMP), 3,4-ethylenedioxythiophene (EDOT), and 3,4-phenylenedioxythiophene (PheDOT), respectively, to yield copolymers P(OE3)-D, P(OE3)-E, and P(OE3)-Ph. At a dopant concentration of 5 mM FeTos3, the electrical conductivities of these copolymers vary significantly (ranging between 9 and 195 S cm–1) with the EDOT copolymer, P(OE3)-E, achieving the highest electrical conductivity. UV–vis–NIR and X-ray spectroscopies show differences in both susceptibility to oxidative doping and extent of oxidation for the P(OE3) series, with P(OE3)-E being the most doped. Wide-angle X-ray scattering measurements indicate that P(OE3)-E generally demonstrates the lowest paracrystallinity values in the series, as well as relatively small π–π stacking distances. The significant (i.e., order of magnitude) increase in electrical conductivity of doped P(OE3)-E films versus doped P(OE3)-D or P(OE3)-Ph films can therefore be attributed to P(OE3)-E exhibiting both the highest carrier ratios in the P(OE3) series, along with good π–π overlap and local ordering (low paracrystallinity values). Furthermore, these trends in the extent of doping and paracrystallinity are consistent with the reduced Fermi energy level and transport function prefactor parameters calculated using the semilocalized transport (SLoT) model. Observed differences in carrier ratios at the transport edge (c t) and reduced Fermi energies η(c) suggest a broader electronic band (better overlap and more delocalization) for the EDOT-incorporating P(OE3)-E polymer relative to P(OE3)-D and P(OE3)-Ph. Ultimately, we rationalize improvements in electrical conductivity due to microstructural and doping enhancements caused by EDOT incorporation, a structure–property relationship worth considering in the future design of highly electrically conductive systems.
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An
pulsed heating atomic layer deposition (PH-ALD) technique is used to grow heteroepitaxial ZnO thin films on
-plane sapphire with temperature-sensitive metalorganic precursors. During metalorganic ...precursor delivery, the substrate is maintained at a base temperature of 110 °C to prevent thermal decomposition of the precursors. After the substrate is sequentially exposed to the metalorganic precursor and water co-reactant at this low temperature, a high-power resistive heater is used to rapidly heat the substrate to between 400 and 900 °C to drive film crystallization. These
heat pulses enable epitaxial growth of (0001) ZnO films on
-plane sapphire. Rocking curves with FWHM of values as low as 0.53° are achieved. In contrast, films deposited entirely at 110 °C appear random polycrystalline and post-deposition annealing to 900 °C achieves only partial "epitaxial character" with a notably different in-plane orientation. Variations in heat pulse temperature and the number of deposition cycles between heat pulses are explored. Epitaxial growth persists up to 5 deposition cycles per heat pulse, with the 2
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FWHM increasing to 1-2°. To further reduce process times, a templating approach is also explored in which a limited number of "template" layers are initially deposited with PH-ALD followed by low-temperature ALD at 110 °C. Epitaxial growth is encouraged with as few as 5 cycles of PH-ALD followed by 495 cycles of low-temperature ALD. Crystal quality further improves by using up to 50 template cycles, with a 2
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FWHM of 1.3°. Epilayers also show enhanced photoluminescence (PL) at room temperature. These results demonstrate how
pulse-heating can be used to promote epitaxial film growth in ALD processes using temperature-sensitive metalorganic precursors.
Abstract Background Elderly patients with heart failure (HF) have a worse prognosis than younger patients. We wished to study whether elders benefit from natriuretic peptide-guided HF care in this ...single-center study. Methods and Results A total of 151 patients with HF resulting from left ventricular systolic dysfunction (LVSD) were treated with HF treatment by standard-of-care (SOC) management or guided by N-terminal pro-B type natriuretic peptide (NT-proBNP) values (with a goal to lower NT-proBNP ≤1000 pg/mL) over 10 months. The primary end point for this post-hoc analysis was total cardiovascular events in 2 age categories (<75 and ≥75 years). In those ≥75 years of age (n = 38), NT-proBNP values increased in the SOC arm (2570 to 3523 pg/mL, P = .01), but decreased in the NT-proBNP–guided arm (2664 to 1418 pg/mL, P = .001). Elderly patients treated with SOC management had the highest rate of cardiovascular events, whereas the elderly with NT-proBNP management had the lowest rate of cardiovascular events (1.76 events per patient versus 0.71 events per patient, P = .03); the adjusted logistic odds for cardiovascular events related to NT-proBNP–guided care for elders was 0.24 ( P = .008), whereas in those <75 years (n = 113), the adjusted logistic odds for events following NT-proBNP–guided care was 0.61 ( P = .10). Conclusions Natriuretic peptide–guided HF care was well tolerated and resulted in substantial improvement in cardiovascular event rates in elders (Clinical Trials.Gov #00351390).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Real-time PCR assays using TaqMan or Molecular Beacon probes were developed and optimized for the quantification of total bacteria, the nitrite-oxidizing bacteria Nitrospira, and Nitrosomonas ...oligotropha-like ammonia oxidizing bacteria (AOB) in mixed liquor suspended solids (MLSS) from a municipal wastewater treatment plant (WWTP) using a single-sludge nitrification process. The targets for the real-time PCR assays were the 16S rRNA genes (16S rDNA) for bacteria and Nitrospira spp. and the amoA gene for N. oligotropha. A previously reported assay for AOB 16S rDNA was also tested for its application to activated sludge. The Nitrospira 16S rDNA, AOB 16S rDNA, and N. oligotropha-like amoA assays were log- linear over 6 orders of magnitude and the bacterial 16S rDNA real-time PCR assay was log-linear over 4 orders of magnitude with DNA standards. When these real-time PCR assays were applied to DNA extracted from MLSS, dilution of the DNA extracts was necessary to prevent PCR inhibition. The optimal DNA dilution range was broad for the bacterial 16S rDNA (1000-fold) and Nitrospira 16S rDNA assays (2500-fold) but narrow for the AOB 16S rDNA assay (10-fold) and N. oligotropha- like amoA real-time PCR assay (5-fold). In twelve MLSS samples collected over one year, mean cell per L values were 4.3 ± 2.0 × 1011 for bacteria, 3.7 ± 3.2 × 1010 for Nitrospira, 1.2 ± 0.9 × 1010 for all AOB, and 7.5 ± 6.0 × 109 for N. oligotropha-like AOB. The percent of the nitrifying population was 1.7% N. oligotropha-like AOB based on the N. oligotropha amoA assay, 2.9% total AOB based on the AOB 16S rDNA assay, and 8.6% nitrite-oxidizing bacteria based on the Nitrospira 16S rDNA assay. Ammonia-oxidizing bacteria in the wastewater treatment plant were estimated to oxidize 7.7 ± 6.8 fmol/hr/cell based on the AOB 16S rDNA assay and 12.4 ± 7.3 fmol/hr/cell based on the N. oligotropha amoA assay.
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Poly(3,4-ethylene dioxythiophene) (PEDOT) has a high theoretical charge storage capacity, making it of interest for electrochemical applications including energy storage and water desalination. ...Nanoscale thin films of PEDOT are particularly attractive for these applications to enable faster charging. Recent work has demonstrated that nanoscale thin films of PEDOT can be formed using sequential gas-phase exposures
via
oxidative molecular layer deposition, or oMLD, which provides advantages in conformality and uniformity on high aspect ratio substrates over other deposition techniques. But to date, the electrochemical properties of these oMLD PEDOT thin films have not been well-characterized. In this work, we examine the electrochemical properties of 5-100 nm thick PEDOT films formed using 20-175 oMLD deposition cycles. We find that film thickness of oMLD PEDOT films affects the orientation of ordered domains leading to a substantial change in charge storage capacity. Interestingly, we observe a minimum in charge storage capacity for an oMLD PEDOT film thickness of ∼30 nm (60 oMLD cycles at 150 °C), coinciding with the highest degree of face-on oriented PEDOT domains as measured using grazing incidence wide angle X-ray scattering (GIWAXS). Thinner and thicker oMLD PEDOT films exhibit higher fractions of oblique (off-angle) orientations and corresponding increases in charge capacity of up to 120 mA h g
−1
. Electrochemical measurements suggest that higher charge capacity in films with mixed domain orientation arise from the facile transport of ions from the liquid electrolyte into the PEDOT layer. Greater exposure of the electrolyte to PEDOT domain edges is posited to facilitate faster ion transport in these mixed domain films. These insights will inform future design of PEDOT coated high-aspect ratio structures for electrochemical energy storage and water treatment.
Orientation of ordered domains in oMLD PEDOT thin films changes with thickness, affecting ion uptake rate and electrochemical device applications.
Wood is a universal building material. While highly versatile, many of its critical properties vary with water content (e.g., dimensionality, mechanical strength, and thermal insulation). Treatments ...to control the water content in wood have many technological applications. This study investigates the use of single-cycle atomic layer deposition (1cy-ALD) to apply <1 nm Al2O3, ZnO, or TiO2 coatings to various bulk lumber species (pine, cedar, and poplar) to alter their wettability, fungicidal, and thermal transport properties. Because the 1cy-ALD process only requires a single exposure to the precursors, it is potentially scalable for commodity product manufacturing. While all ALD chemistries are found to make the wood’s surface hydrophobic, wood treated with TiO2 (TiCl4 + H2O) shows the greatest bulk water repellency upon full immersion in water. In situ monitoring of the chamber reaction pressure suggests that the TiCl4 + H2O chemistry follows reaction-rate-limited processing kinetics that enables deeper diffusion of the precursors into the wood’s fibrous structure. Consequently, in humid or moist environments, 1cy-ALD (TiCl4 + H2O) treated lumber shows a 4 times smaller increase in thermal conductivity and improved resistance to mold growth compared to untreated lumber.
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