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Highly efficient removal of phosphonates from water by a combined Fe(III)/UV/co-precipitation process
摘要： Considerable amount of phosphorous is present as organic phosphonates (usually in the form of metal complexes, e.g., Ca(II)-phosphonate) in domestic and industrial effluents, which cannot be effectively removed by traditional processes for phosphate. Herein, we employed a proprietary process, i.e., Fe(III) displacement/UV irradiation/co-precipitation (denoted Fe(III)/UV/NaOH), to enable an efficient removal of Ca(II)-phosphonate complexes from water. The combined process includes three basic steps, i.e., Fe(III) replacement with the complexed Ca(II) to form Fe(III)-phosphonate of high photo-reactivity, UV-mediated degradation of Fe(III)-phosphonate to form phosphate and other intermediates, and the final phosphorous removal via co-precipitation at pH=6. The operational conditions for the combined process to remove a typical phosphonate Ca(II)-NTMP (nitrilotrismethylenephosphonate) are optimized, where ~60% NTMP is transformed to phosphate with the total phosphorous reduction from 1.81 mg/L to 0.17 mg/L. Under UV irradiation, the cleavage of NTMP is identified at the C-N and C-P bonds to form the intermediate products and phosphate in sequence. Also, the combined process is employed for treatment of two authentic effluents before and after activated sludge treatment, resulting in the phosphorous drop from 4.3 mg/L to 0.23 mg/L and from 0.90 mg/L to 0.14 mg/L respectively, which is much superior to other processes including Fenton/co-precipitation. In general, the combined process exhibits great potential for efficient removal of phosphonates from contaminated waters.
关键词： Photolysis,Fe(III) replacement,Advanced treatment,Phosphonates
更新于2025-09-23 15:22:29
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Heteroleptic Ir(III)N6 Complexes with Long-Lived Triplet Excited States and In Vitro Photobiological Activities
摘要： A series of cationic heteroleptic iridium(III) complexes bearing tris-diimine ligands [Ir(phen)2(R-phen)]3+ (R-phen = phenanthroline (1), 3,8-diphenylphenanthroline (2), 3,8-dipyrenylphenanthroline (3), 3-phenylphenanthroline (4), 3-pyrenylphenanthroline (5), and 3,8-diphenylethynylphenanthroline (6)) were synthesized and characterized. These complexes possessed phen ligand-localized 1π,π* transitions below 300 nm, and charge transfer (1CT) and/or 1π,π* transitions between 300 and 520 nm. In 1, 2, 4, and 6, the low-energy bands were mixed 1CT/1π,π*. However, the increased π-donating ability of the pyrenyl substituent(s) in 3 and 5 split the low-energy bands into a pyrene-based 1π,π* transition at 300-380 nm and an intraligand charge transfer (1ILCT) transition at 380-520 nm. All complexes were emissive at room temperature in CH3CN, but the parentage of the emitting state varied depending on the R substituent(s). Complex 1 exhibited predominantly phen ligand-localized 3π,π* emission mixed with metal-to-ligand charge transfer (3MLCT) character, while the emission of 2, 4, and 6 was predominantly from the excited-state with 3π,π*/3ILCT/3MLCT character. The emission from 3 and 5 was dominated by pyrene-based 3π,π* states mixed with 3ILCT character. The different natures of the lowest triplet excited states were also reflected by the different spectral features and lifetimes of the triplet transient absorption of these complexes. Complexes 3 and 5 had singlet oxygen quantum yields as high as 81 and 72%, respectively. Both gave submicromolar phototoxicities toward cancer cells (SK-MEL-28 human melanoma) and bacteria (S. aureus and S. mutans) with visible light activation (and marginal to no photobiological activity with red light). Their visible-light phototherapeutic indices (PIs) toward SK-MEL-28 cells were 248 for 3 and >435 for 5; PIs were lower in bacteria (≤62) due to their inherent antimicrobial activities. Both complexes were shown to produce substantial amounts of intracellular reactive oxygen species (ROS), which may account for their photobiological activities.
关键词： photophysics,photodynamic therapy,long-lived triplet excited state,antimicrobial,photobiological activities,reactive oxygen species,heteroleptic Ir(III) trisdiimine complexes
更新于2025-09-23 15:22:29
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Recent advances in III-Sb nanowires: from synthesis to applications
摘要： The excellent properties of III-V semiconductors have make them intriguing candidates for next-generation electronics and optoelectronics. Their nanowire counterparts further provide interesting geometry and quantum confinement effect which benefit various applications. Among many members of all III-V semiconductors, III-antimonide nanowires have attracted significant research interest due to their narrow direct bandgap and high carrier mobility. However, due to the difficulty of nanowire fabrication, the development of III-antimonide nanowires and their corresponding applications are always a step behind the other III-V semiconductors. Until recent years, because of the advance in the understanding and the fabrication technique, electronic and optoelectronic device based on III-antimonide nanowires with novel performance have been fabricated. In this review, we will focus on the development of the synthesis of III-antimonide nanowire using different techniques and strategies for fine-tuning the crystal structure, composition as well as fabricating their corresponding heterostructures. With such development, the recent progress in the applications of III-antimonide nanowires in electronics and optoelectronics is also surveyed. All these discussion would give valuable guidelines to the design of III-antimonide nanowires for next-generation device utilizations.
关键词： synthesis,application,nanowire,III-antimonide
更新于2025-09-23 15:22:29
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Pyroelectric Property of Binary Nitrides (AlN, GaN and InN)
摘要： The pyroelectric (PY) property of binary nitrides (AlN, GaN and InN) has been explored theoretically. The spontaneous and piezoelectric (PZ) polarization modifies the thermal conductivity of these nitrides. The thermal conductivities as a function of temperature including and excluding the polarization mechanism (kp and k) predict a transition temperature (T p) between primary and secondary PY effects. Below T p, thermal conductivity kp is lower than k. This is due to negative thermal expansion in binary nitrides. Above T p, kp is greater than k. kp is significantly contributed by PZ polarization due to thermal expansion which is the reason of secondary PY effect. The transition temperature T p for AlN, GaN and InN has been predicted as 100 K, 70 K and 60 K, respectively. This study suggests that thermal conductivity study can reveal PY property in semiconductors.
关键词： Thermal expansion,Thermal property,Pyroelectric coefficient,III–V Binary nitride,Built-in polarization
更新于2025-09-23 15:22:29
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Template Synthesis, Spectral, Thermal and Glucose Sensing of Pr3+ Complexes of Metformin Schiff-Bases
摘要： Schiff-bases of metformin with each of salicylaldehyde (HL1); 2,3-dihydroxybenzaldehyde (H2L2); 2,4-dihydroxybenzaldehyde (H2L3); 2,5-dihydroxybenzaldehyde (H2L4); 3,4-dihydroxybenzaldehyde (H2L5) and 2-hydroxynaphthaldehyde (HL6) and their complexes with Pr(III) were synthesized by template reaction. The complexes were characterized through elemental analysis, conductivity and magnetic moment measurements, IR, UV-Vis., fluorescence, GC-MS and XRD spectroscopy. The complexes exhibit a series of characteristic emission bands for Pr3+ ion in the 481-472 and 590-580 nm range with a 318-332 nm excitation source. The complexes have eight coordinated structure with the formulae [PrL1-4,6(NO3)2(H2O)3].nH2O where n = 1, 1?, 3, 4, 4 and [PrL5(NO3)(H2O)5].2H2O. The suggested stereochemistry was confirmed using TGA, DTG and DTA analysis and a mechanism for thermal decomposition was proposed. Coates-Redfern equation was used to calculate kinetic and thermodynamic parameters of the main decomposition step. The utility of the complexes towards the detection of glucose at physiologically relevant pH in phosphate buffer using UV-Vis and fluorescence spectroscopy as well as viscosity measurements are tried where the association constants were calculated.
关键词： Pr(III) complexes,Spectral and thermal properties,Glucose sensing,Metformin Schiff-bases
更新于2025-09-23 15:22:29
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Inkjet-printed phosphorescent Iridium(III) complex based paper sensor for highly selective detection of Hg2+
摘要： First of its kind inkjet-printed phosphorescent Iridium(III) complex [Ir(TPQ)2(4-EO2-pic)] paper based chemosensor has been developed for Hg2+ ions. The probe is highly selective towards mercury analyte over other metal ions (Cu2+, Ca2+, Co2+, Cd2+, Pb2+, Zn2+, Ni2+, Mg2+, Mn2+, Al3+, Fe3+, La3+, Ag+, K+, Na+ and Li+). [Ir(TPQ)2(4-EO2-pic)] complex solution gave a visible color change from orange to yellow and significant phosphorescence quenching. Upon addition of aqueous Hg2+, the [Ir(TPQ)2(4-EO2-pic)] inkjet-printed paper gave a significant color change in both normal and UV light. The detection limit was found out as 1.78 × 10-8 M. Cyclic voltammetry (CV) studies were conducted to explore the further utility of [Ir(TPQ)2(4-EO2-pic)] as electrochemical sensor for Hg2+ ions in CH3CN / H2O (v/v = 1/1). The oxidation wave intensity of [Ir(TPQ)2(4-EO2-pic)] at 0.98 V decreased and new reversible oxidation wave was appeared at 0.91 V The binding ratio of the [Ir(TPQ)2(4-EO2-pic)]-Hg2+ complex was determined to be 1:1 according to the Job’s Plot. The probable binding modes of these [Ir(TPQ)2(4-EO2-pic)] with Hg2+ have also been suggested on the basis of the 1H-NMR titration, absorption and luminescence studies.
关键词： Phosphorescent,Iridium(III) complex,Inkjet-printed,Paper sensor,Hg2+ detection
更新于2025-09-23 15:21:21
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Carrier concentration and transport in Be-doped InAsSb for infrared sensing applications
摘要： Accurate p-type doping of the active region in III-V infrared detectors is essential for optimizing the detector design and overall performance. While most III-V detector absorbers are n-type (e.g., nBn), the minority carrier devices with p-type absorbers would be expected to have relatively higher quantum efficiencies due to the higher mobility of minority carrier electrons. However, there are added challenges to determining the hole carrier concentration in narrow bandgap InAsSb due to the potential for electron accumulation at the surface of the material and at its interface with the layer grown directly below it. Electron accumulation layers form high conductance electron channels that can dominate both resistivity and Hall-effect transport measurements. Therefore, to correctly determine the bulk hole concentration and mobility, temperature- and magnetic-field-dependent transport measurements in conjunction with Multi-Carrier Fit analysis were utilized on a series of p-doped InAs0.91Sb0.09 samples on GaSb substrates. The resulting hole concentrations and mobilities at 77 K (300 K) are 1.6×1018 cm-3 (2.3×1018 cm-3) and 125 cm2 V-1 s-1 (60 cm2 V-1 s-1), respectively, compared with the intended Be-doping of ~2×1018 cm-3. A surface treatment experiment is conducted to associate one of the electron conducting populations to the surface. Variable temperature (15 – 390 K) measurements confirmed the different carrier species present in the sample and enabled the extraction of the bulk heavy hole, interface carriers and surface electron transport properties. For the bulk carrier, a thermal activation of intrinsic carriers is identified at high temperatures with a bandgap of EG ~ 258 meV and the low temperature data suggests an activation energy of EA ~ 22 meV for the Be dopant atoms. Finally, temperature analysis confirms a surface carrier electron with resulting mobilities and sheet concentrations at 30 K (300 K) of 4500 cm2 V-1 s-1 (4300 ± 100 cm2 V-1 s-1) and 5.6×1010 cm-2 (6×1010 ± 2×1010 cm-2), respectively.
关键词： Hall-effect measurements,magneto-transport,beryllium doping,III-V infrared detectors,InAsSb
更新于2025-09-23 15:21:21
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[IEEE 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Shenzhen, China (2018.6.6-2018.6.8)] 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Characterization of Transient Threshold Voltage Shifts in Enhancement- and Depletion-mode AlGaN/GaN Metal-Insulator-Semiconductor (MIS)-HEMTs
摘要： Both enhancement- and depletion-mode AlGaN/GaN metal-insulator-semiconductor HEMTs were fabricated with Al2O3 as the gate dielectric formed by atomic layer deposition (ALD). With the common problems of threshold voltage hysteresis in AlGaN/GaN MIS-HEMTs, DC I-V and fast transient frequency-dependent C-V measurements were performed to characterize the threshold voltage shifts ?Vth and hence to systematically study the underlying mechanism. The experimental results reveal that ?Vth can be as high as 1.0 V at VG,max = 5 V in transient I-V measurements despite the much lower values of 0.42 V in static and CV measurements. This has significant implications in using AlGaN/GaN MIS-HEMTs for high voltage switching applications. Besides, multi-frequency C-V measurements show that the primary ?Vth is frequency independent but the second onset of voltage shifts (?V2) shows obvious frequency dependence. These results imply the likely mechanism of slow (deep) Al2O3 interface traps accounting for ?V1 hysteresis, and fast (shallow) interface traps accounting for ?V2.
关键词： AlGaN/GaN MIS-HEMT,Al2O3/III-N interface traps (fast and slow) and threshold voltage hysteresis.
更新于2025-09-23 15:21:21
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Numerical analysis of carrier-depletion InGaAsP optical modulator with lateral PN junction formed on III–V-on-insulator wafer
摘要： We numerically investigated the modulation characteristics of a carrier-depletion InGaAsP optical modulator with a lateral PN junction fabricated on a III–V-on-insulator (III–V-OI) wafer. Owing to the large electron-induced refractive index change in InGaAsP, the InGaAsP optical modulator with a doping concentration of 2 ' 1018 cm%3 in the PN junction exhibited a phase modulation e?ciency VπL of 0.17 Vcm, which was 6 times smaller than that of a Si modulator with the same structure. The doping concentration dependence revealed that αVπL, which is a product of the insertion loss α and VπL, can signi?cantly be improved using InGaAsP when the doping concentration was as high as 1 ' 1018 cm%3. Thus, we concluded that the phase modulation e?ciency and insertion loss can be improved simultaneously using InGaAsP instead of Si for a carrier-depletion optical modulator with a lateral PN junction.
关键词： InGaAsP,carrier-depletion,optical modulator,numerical analysis,III–V-on-insulator
更新于2025-09-23 15:21:21
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Collective Die Direct Bonding for Photonic on Silicon
摘要： Optoelectronic devices usually needs heterostructure integration with III/V devices integrated on silicon circuits. As throughput placement are more important than placement precision, collective die to wafer bonding is an interesting process for these applications. Moreover as light should be propagated through the bonding interface, minimizing interfacial material is mandatory. Collective direct bonding of die to wafer is then proposed. The bonding yield as well as the first placement accuracy is evaluated.
关键词： III/V integration,Collective Die Direct Bonding,Silicon Photonics,Photonic on Silicon
更新于2025-09-23 15:21:21