High Μe Research Articles

Influence of P and C co-alloying on soft magnetic properties and crystallization behavior of FeSiBPCCu nanocrystalline alloys

In this study, multicomponent synergistic effects were adopted to enhance the glass-forming ability (GFA), processing window (PW), thermal stability, and soft magnetic properties (SMPs) of FeCuSiB nanocrystalline alloys (NAs) with high Fe and Cu contents via P and C co-alloying. The co-addition of P and C is beneficial for enhancing the GFA, expanding the PW, and increasing the crystallization resistance of the compound phases in present FeCuSiBPC alloys. Consequently, the Fe81.5Cu1.7Si3.8B9P3C1 alloy exhibited a large optimum TA window of up to 100 °C and a large tA window of 40 min for nanocrystallization. Crystallization kinetic analysis showed that the co-addition of P and C led to a high-frequency factor (v) in the precipitation of α-Fe crystals, which was related to the high nanocrystal density (Nd) of α-Fe. This result may be attributed to the nucleation of α-Fe by Cu and CuP clusters. Additionally, the co-addition of P and C increased the growth active energy (Ep) of the α-Fe crystals because of their larger atomic diffusion resistance. The high Nd and Ep values led to the formation of fine nanostructures and excellent SMPs in FeCuSiBPC alloys. Therefore, the Fe81.5Cu1.7Si3.8B9P3C1 NA obtained by annealing at 420 °C for 30 min exhibited excellent SMPs with a Bs of up to 1.78 T, a low Hc of 7.5 A/m, and a high μe of 9863 (@1kHz). This study provides technical and theoretical guidance for optimizing the composition and processability of NAs with high Fe and Cu contents, paving the way for mass production of high-performance soft magnetic NAs.

Single crystal growth and transport properties of narrow-bandgap semiconductor RhP2

Abstract We report the growth of high-quality single crystals of RhP2, and systematically study its structure and physical properties by transport, magnetism, and heat capacity measurements. Single-crystal x-ray diffraction reveals that RhP2 adopts a monoclinic structure with the cell parameters a = 5.7347(10) Å, b = 5.7804(11) Å, and c = 5.8222(11) Å, space group P21/c (No. 14). The electrical resistivity ρ(T) measurements indicate that RhP2 exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions, respectively. The temperature-dependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration. We find that RhP2 has a high mobility μ e ∼ 210 cm2⋅V−1⋅s−1 with carrier concentrations n e ∼ 3.3 × 1018 cm−3 at 300 K with a narrow-bandgap feature. The high mobility μ e reaches the maximum of approximately 340 cm2⋅V−1⋅s−1 with carrier concentrations n e ∼ 2 × 1018 cm−3 at 100 K. No magnetic phase transitions are observed from the susceptibility χ(T) and specific heat C p(T) measurements of RhP2. Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.

Tailoring the thermal stability and soft magnetic properties of Fe80-xNixSi7B8P4Cu1 amorphous nanocrystalline alloys based on the magnetic domain structure

Structure, crystallization behavior, dynamic domains, and magnetic properties of as-quenched and annealed Fe80-xNixSi7B8P4Cu1 (x = 0, 1, 2, 3 and 4) alloy ribbons have been investigated. It finds that the partial substitution of Ni for Fe promotes the formation of amorphous structure. We have determined the critical spinning speed for the formation of pre-existing α-Fe cluster structures. In addition, a little increase in Ni content effectively inhibits the excessive growth of the α-Fe grains, which contributes to the reduction of grain size and Hc. Moreover, the role of Ni on the magnetic domain structures and its correlation medel was established. After proper annealing treatment, the Fe79Ni1Si7B8P4Cu1 nanocrystalline alloy exhibited excellent soft-magnetic properties including a high Bs of 1.58 T, a low Hc of 2.48 A/m and a high μe of 16400, which is closely related to the high volume fraction of α-Fe grains and uniform refinement of magnetic domains which is more conducive to the migration and rotation of magnetic domains.

Microstructure evolution and soft magnetic properties of Fe-based nanocrystalline soft magnetic composites coated with lubricant

Here, the influence of zinc stearate on the microstructure and soft magnetic properties of the Finemet nanocrystalline soft magnetic composites (NSMCs) was systematically investigated. The results demonstrate that the core loss (Pcv) decreases and the effective permeability (μe) increases of the NSMCs with increasing zinc stearate from 0 wt% to 2.0 wt%, which can be attributed to the reduction of residual stress during compaction. Further increasing zinc stearate up to 3.0 wt%, the Pcv increases sharply, while the μe shows a decreasing trend. It can be considered that the addition of excess lubricant decomposes to CO2 during annealing, which deteriorates the magnetic properties. After annealing at 560 °C, a thin hybrid layer of only about 53.6 nm containing iron phosphate, ZnO, and SiO2 is formed in the NSMCs with 2.0 wt% zinc stearate, which exhibits excellent soft magnetic properties such as low Pcv of 174 kW/m3 and high μe of 66.7 at Bm = 0.1 T for 50 kHz. In addition, loss separation has been carried out and suggests that the addition of lubricant mainly affects hysteresis loss in the total energy loss of NSMCs.

Study of the Soft Magnetic Properties of FeSiAl Magnetic Powder Cores by Compounding with Different Content of Epoxy Resin.

FeSiAl is a commonly used soft magnetic material because of its high resistivity, low core loss, and low cost. In order to systematically study the effect of epoxy resin (EP) on the insulated coating and pressing effect of FeSiAl magnetic powders, six groups of composite powders and their corresponding soft magnetic powder cores (SMPCs) were prepared by changing the content of EP, and the soft magnetic properties of the powders and SMPCs were characterized. The results showed that FeSiAl powders exhibited good sphericity and morphology. The Ms of FeSiAl/EP composite powders was between 117.4-124.8 emu·g-1 after adding (0.3, 0.5, 0.7, 1, 1.5, and 2 wt. %) EP. The permeability μe of SMPCs increased first and then decreased with the increase in EP content. Among them, when the EP content was 1 wt. %, the corresponding SMPCs had the highest μe and excellent DC bias performance (63%, 100 Oe). In the whole test frequency range (50~1000 kHz), SMPCs with 1 wt. % EP content had the lowest core loss (1733.9 mW·cm-3 at 20 mT and 1000 kHz). After that, the loss separation study in the low-frequency range (50~250 kHz) was conducted, and the hysteresis loss and eddy current loss of SMPCs with 1 wt. % EP content were also the lowest. In addition, SMPCs also exhibited the best overall performance when the EP content was 1 wt. %. The results of this study can guide the design of composite insulation coating schemes and promote the development of soft magnetic materials for medium and high frequency applications.

A Hybrid Acceptor-Modulation Strategy: Fluorinated Triple-Acceptor Architecture for Significant Enhancement of Electron Transport in High-Performance Unipolar n-Type Organic Transistors.

The development of unipolar n-type semiconducting polymers with electron mobility (µe ) over 5cm2 V-1 s-1 remains a massive challenge in organic semiconductors. Diketopyrrolopyrrole (DPP) has proven to be a successful unit for high-performance p-type and ambipolar polymers. However, DPP's moderate electron-accepting capability leads to the shallow frontier molecular orbital (FMO) levels of the resultant polymers and hence limit the µe in unipolar n-type organic transistors. Herein, this issue has been addressed by using a hybrid acceptor-modulation strategy based on DPP-containing "fluorinated triple-acceptor architecture", namely DPP-difluorobenzothiadiazole-DPP (DFB). Compared with DFB's non-fluorinated counterpart, DFB features deeper FMO levels and a shape-persistent framework. Therefore, a series of DFB-based polymers demonstrate planar backbones and lowered FMO levels by ≈0.10 to 0.25eV versus that of the control polymer. Intriguingly, all DFB-polymers exhibit excellent unipolar n-type transistor performances. Notably, a full-locked backbone conformation and high crystallinity with crystalline coherence length of 524Å are observed for pDFB-TF, accounting for its high µe of 5.04cm2 V-1 s-1 , which is the highest µe value for DPP-based unipolar n-type polymers reported to date. This work demonstrates that the strategy of "fluorinated triple-acceptor architecture" opens a new path towards high-performance unipolar n-type semiconducting polymers.

Effects of heat treatment and compaction pressure on the microstructure and magnetic properties of core-shell structured FeSiBNbCu/SiO2 soft magnetic composites

Here, the FeSiBNbCu/SiO2 soft magnetic composites (SMCs) with core-shell structure were successfully designed and fabricated using nanocrystalline powders as seeds and SiO2 were grown by sol-gel technique onto the surface of the seed particles. We systematically investigated the influences of annealing temperature and compaction pressure on the micromorphology, chemical structure and soft magnetic properties of the SMCs. The results demonstrate that a large number of submicron-sized SiO2 particles are uniformly deposited on the surface of the powders, which significantly improves the insulating characteristics between the magnetic powders. Also, the effective permeability μe increases and the core loss Pcv decreases with increasing annealing temperature from 480 °C to 550 °C, which is attributed to the relaxation of internal stress and the increase of volume fraction of α-Fe(Si) grains. Furthermore, an increase in compaction pressure effectively increases the densification and reduces the porosity, which facilitates a denser microstructure. Under the combined effect of optimal annealing temperature and compaction pressure, the SMCs exhibit high μe of 84 and low Pcv of 174 kW/m3 at 50 kHz for Bm = 0.1 T. This work provides a new strategy for the construction of core-shell structure and a comprehensive understanding of the relationship between process parameters and microstructure, which is of great guiding significance for industrial production.

Ultrafine-grained microstructure and controllable magnetic domains in Fe-based nanocrystalline alloys with excellent magnetic properties induced by hot isostatic pressing

The coarsening and inhomogeneous distribution of nano-grains caused by traditional heat treatment processes are the biggest obstacles for obtaining ultrahigh permeability and excellent comprehensive soft magnetic properties in Fe-based nanocrystalline alloys. Here, we propose a new strategy to control grain growth and magnetic anisotropy, by introducing isotropic compressive stress field in the annealing process to optimize the magnetic properties. Compared with conventional isothermal annealing, the coupling of stress-temperature field generated by hot isostatic pressing (HIP) induced the microstructure, magnetic domain evolution and magnetic properties in Si-rich Fe73.5Si15.5B7Nb3Cu1 amorphous ribbons have been systematically investigated. We demonstrate that HIP treatment promotes more Si atoms to dissolve in Fe unit cell to form Fe(Si) solid solution causing an increase in interplanar spacing. Also, the high-density Cu clusters precipitate in the amorphous matrix upon HIP serving as nucleation sites for α-Fe(Si) grains, which facilitate a high volume fraction, uniform and ultrafine-grained microstructure. Moreover, the existence of stress field introduces induced anisotropy effectively controls the magnetization mechanism and magnetic structure evolution. Furthermore, the Fe73.5Si15.5B7Nb3Cu1 nanocrystalline alloy treated by HIP exhibit excellent comprehensive magnetic properties, such as high Ms, high μe, low Pcv, low AC Hc and high Br/Bm.

Resource-saving production of Fe-based amorphous alloys from carbothermal reduction of high-phosphorus oolitic iron ore

Energy-saving and resource-friendly production of Fe-based soft-magnetic materials is of paramount importance for the development of green economy. In this study, an innovative process for fabricating Fe-based amorphous alloys from high-phosphorus oolitic iron ore was developed with the combination of ironmaking and melt-spinning techniques. By using the developed process, iron and phosphorus in high-phosphorus oolitic iron ore can be simultaneously utilized. During the direct carbothermal reduction process of high-phosphorus oolitic iron ore, oolitic hematite and apatite were first reduced to form liquid iron phase and absorb P2 gas, resulting in the enrichment of P element in iron phase. Fe-P alloys with different P and C content can be easily obtained by tailoring the C/O ratio. The reduced Fe-P alloys with high εFe of 96.4% and εP of 70.7% are ideal raw materials for preparing Fe-based soft-magnetic alloys. Fe80P10C9Si1 amorphous alloy was successfully obtained after composition adjustment. The high AFA of rod sample with diameter up to 1 mm and good magnetic softness of the ribbon samples including high Bs of 1.54 T, low Hc of 3.6 A/m, high μe of 30 × 103 with excellent frequency stability prove the effectiveness of the designed process. These findings are of great significance to lay the foundation for the recycling of resources and preparation of high performance soft-magnetic alloys from iron ores.

Thiazoloisoindigo-based ambipolar polymers for excellent balanced hole and electron mobility

The copolymerization of thiophene-flanked thiazoisoindigo (TzII) and thiophene-flanked dipyrrolopyrrolidone (DPP) leads to an ambipolar polymer with high and balanced charge carrier mobility (highest μe: 7.63 and highest μh: 6.11 cm2 V−1 s−1, respectively).

Fe-based amorphous alloys with superior soft-magnetic properties prepared via smelting reduction of high-phosphorus oolitic iron ore

Fe-based amorphous alloys generally suffer from the impurities in industrial raw materials and the high cost of pure raw materials. In this work, a revolutionary way for preparing Fe-based amorphous alloys from the refractory high-phosphorus oolitic iron ore with the combination of smelting reduction and melt-spinning was proposed for the simultaneously utilization of Fe and P elements. By using the smelting reduction, Fe–P alloys with high Fe and P recovery rate of 99% and 92% can be obtained, and the C content in the resultant Fe–P alloys can be accurately tailored by adjusting the C/O ratio. For the implementation of the developed process, the reduced Fe–P alloys with significantly different C content and the corresponding Fe83P3C1Si2B11, Fe76P5C3.8Si5.7B9.5 and Fe80P10C9Si1 (at. %) amorphous alloys with close C content were chosen. These resultant alloys all exhibit high AFA, low Hc and high μe as well as wide annealing window comparable to that of the alloys prepared with pure raw materials, demonstrating the feasibility of the developed process for energy-saving and resource-friendly production of soft-magnetic materials via smelting reduction of iron ores.

Replacement effect with Ni on high-frequency permeability and core loss characteristics for FeNiPBSiC glassy alloys

The paper aims to develop an excellent soft magnetic glassy alloy with a series of (Fe1−xNix)79P5B12Si3C1 (x = 0, 0.2, 0.4, 0.5, 0.6). The annealing at (Tg-20) K for the 0.4Ni-0.5Ni alloys causes an extremely low coercivity below 1 A/m with very high effective permeability above 5·104 at 1 kHz in the maintenance of high saturation magnetic flux density of ⋍ 1.2 T. Good effective permeability characteristics were recognized as is evidenced from high μe values above 6000 at 1 MHz. The core losses at induction of 100 mT are as low as 43 W/kg for 100 kHz and 1150 W/kg at 1 MHz for the annealed 0.6Ni alloy. Excellent soft magnetic properties are presumably due to the achievement of the fully relaxed glassy state which can be obtained only for the glass-type alloys with SCL region. This complex of magnetic properties is promising for future use as high-frequency type soft magnetic materials.

Disintegrable n‐Type Electroactive Terpolymers for High‐Performance, Transient Organic Electronics

AbstractDegradable organic semiconductors have significant potential for transient and biomedical organic electronics, but there have been only a few studies on fully degradable conjugated polymers (CPs) that achieve high electrical performance. In addition, these examples are limited to p‐type CPs. In this study, a series of fully degradable n‐type CPs, naphthalene diimide (NDI)‐based terpolymer (PNDIT2/IM‐f) are developed. The incorporation of an imine linker (IM) into the CP backbone affords the capability of facile hydrolysis degradation while maintaining efficient π‐conjugations and excellent electrical properties. An additional benefit of this molecular design is the systematic tunability of the degradation characteristics and electrical performance depending on the IM content (fIM). At the optimal point (fIM = 0.45) that enables complete degradation of the polymer under acidic conditions, the resulting PNDIT2/IM‐0.45 film exhibits high electron mobility (μe) of 0.04 cm2 V−1 s−1 in organic field‐effect transistors (OFETs), demonstrating excellent potential as transient OFETs. The high μe value is mainly attributed to the enlarged edge‐on orientations and tighter stacking of PNDIT2/IM‐f crystallites as increasing fIM. Thus, this study provides useful guidelines for the design of fully degradable n‐type CPs and establishes an important correlation between the molecular structure−electronic performance−transient properties.

Titanium Nanopillar Arrays Functioning as Electron Transporting Layers for Efficient, Anti-Aging Perovskite Solar Cells.

Electron transporting layers (ETLs), required to be optically transparent in perovskite solar cells (PSCs) having regular structures, possess a determinant effect on electron extraction and collection. Metal oxides (e.g., TiO2 ) have overwhelmingly served as ETLs, but usually have low electron mobility (μe < 10-2 cm2 V-1 s-1 ) not favorable for photovoltaic conversion. Here, metal oxides are replaced with metals (e.g., Ti with μe ≈ 294 cm2 V-1 s-1 ) that are sculptured via glancing angle deposition to be a close-packed nanopillar array (NaPA), which vertically protrudes on a transparent electrode to obtain sufficient optical transmission for light harvesting in perovskite. Ti NaPAs, whose rough surfaces are passivated with 5 nm thick TiO2 (i.e., Ti NaPAs@TiO2 ) to suppress exciton recombination, lead to the champion power conversion efficiency (PCE) of 18.89% that is superior to that of MAPbI3 PSCs without Ti NaPAs@TiO2 or containing TiO2 NaPAs@TiO2 , owing to high surface wettability, high μe , and relatively low work function of Ti. Furthermore, Ti NaPAs@TiO2 effectively prevents the decomposition of MAPbI3 to achieve long-term shelf stability whereby 50-day aging only causes 15% PCE degradation. This work paves the way toward widening the material spectrum, from semiconductors to metals, to generate a diverse range of ETLs for producing efficient optoelectronic devices with long-term shelf stability.

Crystallography, Morphology, Electronic Structure, and Transport in Non-Fullerene/Non-Indacenodithienothiophene Polymer:Y6 Solar Cells.

Emerging nonfullerene acceptors (NFAs) with crystalline domains enable high-performance bulk heterojunction (BHJ) solar cells. Thermal annealing is known to enhance the BHJ photoactive layer morphology and performance. However, the microscopic mechanism of annealing-induced performance enhancement is poorly understood in emerging NFAs, especially regarding competing factors. Here, optimized thermal annealing of model system PBDB-TF:Y6 (Y6 = 2,2'-((2Z,2'Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]-thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) decreases the open circuit voltage (VOC) but increases the short circuit current (JSC) and fill factor (FF) such that the resulting power conversion efficiency (PCE) increases from 14 to 15% in the ambient environment. Here we systematically investigate these thermal annealing effects through in-depth characterizations of carrier mobility, film morphology, charge photogeneration, and recombination using SCLC, GIXRD, AFM, XPS, NEXAFS, R-SoXS, TEM, STEM, fs/ns TA spectroscopy, 2DES, and impedance spectroscopy. Surprisingly, thermal annealing does not alter the film crystallinity, R-SoXS characteristic size scale, relative average phase purity, or TEM-imaged phase separation but rather facilitates Y6 migration to the BHJ film top surface, changes the PBDB-TF/Y6 vertical phase separation and intermixing, and reduces the bottom surface roughness. While these morphology changes increase bimolecular recombination (BR) and lower the free charge (FC) yield, they also increase the average electron and hole mobility by at least 2-fold. Importantly, the increased μh dominates and underlies the increased FF and PCE. Single-crystal X-ray diffraction reveals that Y6 molecules cofacially pack via their end groups/cores, with the shortest π-π distance as close as 3.34 Å, clarifying out-of-plane π-face-on molecular orientation in the nanocrystalline BHJ domains. DFT analysis of Y6 crystals reveals hole/electron reorganization energies of as low as 160/150 meV, large intermolecular electronic coupling integrals of 12.1-37.9 meV rationalizing the 3D electron transport, and relatively high μe of 10-4 cm2 V-1 s-1. Taken together, this work clarifies the richness of thermal annealing effects in high-efficiency NFA solar cells and tasks for future materials design.

Comparative study of V and Mo on the glass formation and magnetic properties of Fe-Si-B-Cu-Nb-M (M=V, Mo) nanocrystalline for high frequency applications

This paper aimed at improving high-frequency magnetic properties and decreasing material cost of “Finemet”alloy without sacrificing saturation magnetization (Ms) and coercivity (Hc) by minor V and Mo substitution of Nb. Both V and Mo enhanced glass forming ability (GFA) and promoted the precipitation of primary α-Fe particles. Meanwhile, V addition hindered the precipitation of the secondary phase and consequently extended annealing temperature range. After annealing, the Fe73.5Si15.5B9Cu1Nb2V1 and Fe73.5Si15.5B9Cu1Nb2.5Mo0.5 have high Ms of 129.0 and 127.6 emu/g, low Hc of 2.7 and 5.3 A/m, and high μe of 3.6 × 104 and 3.4 × 104 at 200 kHz/0.3V respectively. The order of the effect of Nb, Mo and V on decreasing grain size and coercivity (Hc) is Nb>V>Mo. Besides, the increasing electrical resistivity via adding 1.0 at.% V and 0.5 at.% Mo contributed to a higher and more stable effective permeability (μe) in a wide high frequency range. These advantages for soft magnetic materials are promising for high-frequency applications.

Improvement of SMPs in Fe-Si-B-P-C-Cu-Nb alloys via harmonizing P and B

The effect of P content on crystallization behavior, microstructure, magnetic domain structure, and magnetic properties of Fe81.5Si3B13-xP0.5+xC0.2Cu0.8Nb1 (x = 0, 1, 2, and 3 at. %) alloys have been investigated. The results of XRD and DSC suggest that the moderate increase in P content improves the amorphous forming ability (AFA) of the alloys and enlarges the temperature interval to 153 K between two crystallization peaks. The activation energy indicates that the relative increase in P content prompts the precipitation of α-Fe phase and improves the thermal stability. Through optimal annealing treatments, the nanocrystalline alloy with x = 3 exhibits excellent soft magnetic properties (SMPs), including high Bs above 1.65 T, high µe about 19000, low Hc below 3 A/m and P10/50 around 0.12 W/kg. The microstructures of the alloys annealed at optimal conditions were detected via XRD and TEM, the results of which show that harmonizing P and B not only refines grains but enhances the nanostructure homogeneity. The investigation with magneto-optical Kerr microscopy reveals the magnetic domain evolution of x = 3 alloy including stress domain removing, domain differentiating and broadening process.

A step towards high-performance photovoltaics via three-component P3HT/PANI-graft-rGO nanocomposites

Polyaniline-grafted reduced graphene oxide (PANI-graft-rGO) was synthesized by in situ oxidative polymerization of aniline using amine-terminated rGO (rGO-NH2) as an initiator. Nanosheets were applied as templates for crystallization of regioregular poly(3-hexylthiophene) (P3HT) chains. The resulting nano-hybrids entitled supra(rGO-NH2/P3HT) and supra(PANI-graft-rGO/P3HT) were utilized in the active layers of P3HT:phenyl-C71-butyric acid methyl ester (PC71BM) solar cells to improve the photovoltaic characteristics up to (6.79 mA/cm2, 43%, and 0.65 V) and (13.21 mA/cm2, 64%, and 0.67 V), leading to the efficiencies of 1.90% and 5.66%, respectively. In similar conditions and only via replacing the rGO-NH2 with PANI-graft-rGO, the photovoltaic features were elevated. It could be assigned to the impact of PANI grafts in facilitating th[e surface crystallization of P3HT host chains and thereby in well-arranging the active layer constituents. The PANI mediators may act as both acceptors (accepting the electrons from rGO) and donors (donating the electrons to P3HT crystals) in configuration of supra(PANI-graft-rGO/P3HT) nano-hybrids, thus made the supra(PANI-graft-rGO/P3HT) nanostructures the appropriate candidates in manipulation of cell factors. This phenomenon was comprehended from the escalation in contents of hole (µh) and electron (µe) mobilities and also short circuit current density (Jsc) values. The highest µe (8.9 × 10–3 cm2/V.s) and µh (4.5 × 10–3 cm2/V.s) were acquired for electron-only (Al/supra(PANI-graft-rGO/P3HT):P3HT:PC71BM/Al) and hole-only (indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/supra(PANI-graft-rGO/P3HT):P3HT:PC71BM/Pd) devices. In similar conditions, the charge mobilities were lower in rGO-NH2 based systems either with PC71BM molecules or without them.

Dimethylacetamide-promoted Direct Arylation Polycondensation of 6,6′-Dibromo-7,7′-diazaisoindigo and (E)-1,2-bis(3,4-difluorothien-2-yl)ethene toward High Molecular Weight n-Type Conjugated Polymers

A highly efficient and eco-friendly protocol for the synthesis of an alternating copolymer poly(7,7′-diazaisoindigo-alt-(E)-1,2-bis(3,4-difluorothien-2-yl)ethene) (PAIID-4FTVT) via direct arylation polycondensation (DArP) is presented. Through detailed study, we found that the inhibitory effect of 7,7′-diazaisoindigo on DArP stemmed from the coordination of N atom with catalyst can be overcome by using dimethylacetamide (DMAc) as the co-solvent. Thus, PAIID-4FTVT with number-average molecular weight (Mn) > 100 kDa was synthesized via DArP by optimizing the content of DMAc. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectroscopy revealed that PAIID-4FTVT was defect-free. Top gate and bottom contact (TG/BC) organic thin-film transistors (OTFTs) were fabricated to characterize the semiconducting properties of the polymers. PAIID-4FTVT displayed unipolar n-type characteristics with the electron mobility (µe) strongly dependent on Mn. The highest µe up to 0.25 cm2·V−1·s−1 was achieved with the high molecular weight sample.

Ultra-low cost and energy-efficient production of FePCSi amorphous alloys with pretreated molten iron from a blast furnace

Due to the high sensitivity of amorphous forming ability on purity, Fe-based amorphous alloys are always made with high-purity raw materials which are energy wasting for purification and expensive, thereby limiting their wider application. Here, we proposed an ultra-low cost and energy-efficient production process for Fe-based amorphous alloys, with pretreated molten iron from the blast furnace. Fex(P10C9Si1)5–0.05x (x = 76–82) amorphous alloys with excellent manufacturability and magnetic properties were successfully prepared with the new process. The impurities containing C, P, and Si in the molten iron from a blast furnace were used as useful components, while other minor impurities like Ti and Mn do not apparently affect the GFA and magnetic properties. Attractive magnetic properties, including low Hc of 3.1–5.1 A/m, high μe of 6.1–8.4 × 103 at 1 kHz, high Bs of 1.25–1.48 T were achieved in ribbon samples after optimal annealing. Rod samples with a diameter up to 1.5 mm were readily prepared and exhibit high strength of 3.37 GPa. The ultra-low cost, energy saving effects and excellent soft magnetic properties will render the production process a new generation for Fe-based amorphous alloys and widen the applications.