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Devendra KC Deb Kumar Shah M. Shaheer Akhtar Mira Park Chong Yeal Kim O-Bong Yang Bishweshwar Pant 《Molecules (Basel, Switzerland)》2021,26(11)
This paper numerically explores the possibility of ultrathin layering and high efficiency of graphene as a back surface field (BSF) based on a CdTe solar cell by Personal computer one-dimensional (PC1D) simulation. CdTe solar cells have been characterized and studied by varying the carrier lifetime, doping concentration, thickness, and bandgap of the graphene layer. With simulation results, the highest short-circuit current (Isc = 2.09 A), power conversion efficiency (η = 15%), and quantum efficiency (QE~85%) were achieved at a carrier lifetime of 1 × 103 μs and a doping concentration of 1 × 1017 cm−3 of graphene as a BSF layer-based CdTe solar cell. The thickness of the graphene BSF layer (1 μm) was proven the ultrathin, optimal, and obtainable for the fabrication of high-performance CdTe solar cells, confirming the suitability of graphene material as a BSF. This simulation confirmed that a CdTe solar cell with the proposed graphene as the BSF layer might be highly efficient with optimized parameters for fabrication. 相似文献
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Shekhar KC Roshan K. Dhungana Namrata Khanal Ramesh Giri 《Angewandte Chemie (International ed. in English)》2020,59(21):8047-8051
We report a Ni‐catalyzed regioselective α‐carbonylalkylarylation of vinylarenes with α‐halocarbonyl compounds and arylzinc reagents. The reaction works with primary, secondary, and tertiary α‐halocarbonyl molecules, and electronically varied arylzinc reagents. The reaction generates γ,γ‐diarylcarbonyl derivatives with α‐secondary, tertiary, and quaternary carbon centers. The products can be readily converted to aryltetralones, including a precursor to Zoloft, an antidepressant drug. 相似文献
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Phenothiazine–BODIPY–Fullerene Triads as Photosynthetic Reaction Center Models: Substitution and Solvent Polarity Effects on Photoinduced Charge Separation and Recombination 下载免费PDF全文
Chandra B. KC Gary N. Lim Dr. Vladimir N. Nesterov Prof. Dr. Paul A. Karr Prof. Dr. Francis D'Souza 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):17100-17112
Novel photosynthetic reaction center model compounds of the type donor2–donor1–acceptor, composed of phenothiazine, BF2‐chelated dipyrromethene (BODIPY), and fullerene, respectively, have been newly synthesized using multistep synthetic methods. X‐ray structures of three of the phenothiazine‐BODIPY intermediate compounds have been solved to visualize the substitution effect caused by the phenothiazine on the BODIPY macrocycle. Optical absorption and emission, computational, and differential pulse voltammetry studies were systematically performed to establish the molecular integrity of the triads. The N‐substituted phenothiazine was found to be easier to oxidize by 60 mV compared to the C‐substituted analogue. The geometry and electronic structures were obtained by B3LYP/6‐31G(dp) calculations (for H, B, N, and O) and B3LYP/6‐31G(df) calculations (for S) in vacuum, followed by a single‐point calculation in benzonitrile utilizing the polarizable continuum model (PCM). The HOMO?1, HOMO, and LUMO were, respectively, on the BODIPY, phenothiazine and fullerene entities, which agreed well with the site of electron transfer determined from electrochemical studies. The energy‐level diagram deduced from these data helped in elucidating the mechanistic details of the photochemical events. Excitation of BODIPY resulted in ultrafast electron transfer to produce PTZ–BODIPY.+–C60.?; subsequent hole shift resulted in PTZ.+–BODIPY–C60.? charge‐separated species. The return of the charge‐separated species was found to be solvent dependent. In nonpolar solvents the PTZ.+–BODIPY–C60.? species populated the 3C60* prior to returning to the ground state, while in polar solvent no such process was observed due to relative positioning of the energy levels. The 1BODIPY* generated radical ion‐pair in these triads persisted for few nanoseconds due to electron transfer/hole‐shift mechanism. 相似文献
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Study on Reduction of Energy Consumption in Pulsed Corona Discharge Process for NOx Removal 总被引:4,自引:0,他引:4
Chung Jae-Woo Cho Moo-Hyun Son Byung-Hak Mok Young-Sun Namkung Won 《Plasma Chemistry and Plasma Processing》2000,20(4):495-509
We investigated the reduction of electrical energy consumption in thepulsed corona discharge process for the removal of nitrogenoxides. Hydrocarbon chemical additives used in the laboratory-scaleexperiment are responsible for the enhancement of the NO conversionthrough the chain reactions of free radicals, such as, R, RCO, RO,and others. Electrical energy consumption per converted NO moleculehas a minimum value of 17 eV when pentanol is injected. When ethyleneand propylene are injected, 30 and 22 eV of electrical energy consumptionare required for the conversion of a NO molecule, respectively. The ratioof the pulse-forming capacitance (Ce) to the reactor capacitance (CR)plays an important role in the energy transfer efficiency to thereactor. The maximum energy transfer efficiency of approximately 72%could be obtained by the pulse-forming capacitance, which is 3.4 timeslarger than the reactor capacitance; the maximum NO conversionefficiency was also observed with the same condition. 相似文献
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The components (H3PO4, HNO3, CH3COOH and water) in an etchant solution have been accurately measured in an on-line manner using near-infrared (NIR) spectroscopy by directly illuminating NIR radiation through a Teflon line. In particular, the spectral features according to the change of H3PO4 or HNO3 concentrations were not mainly from NIR absorption themselves, but from the perturbation (or displacement) of water bands; therefore, the resulting spectral variations were quite similar to each other. Consequently partial least squares (PLS) prediction selectivity among the components should be the most critical issue for continuous on-line compositional monitoring by NIR spectroscopy. To improve selectivity of the calibration model, we have optimized the calibration models by finding selective spectral ranges with the use of moving window PLS. Using the optimized PLS models for each component, the resulting prediction accuracies were substantially improved. Furthermore, on-line prediction selectivity was evaluated by spiking individual pure components step by step and examining the resulting prediction trends. When optimized PLS models were used, each concentration was selectively and sensitively varied at each spike; meanwhile, when whole or non-optimized ranges were used for PLS, the prediction selectivity was greatly degraded. This study verifies that the selection of an optimal spectral range for PLS is the most important factor to make Teflon-based NIR measurements successful for on-line and real-time monitoring of etching solutions. 相似文献
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Namkung W. Choe J.Y. Uhm H.S. Ayres V. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(2):149-154
Microwave radiation at the fundamental and harmonic electron cyclotron frequencies generated by a cusptron oscillator is reported. A low-energy, axis-rotating beam of 28-30 kV, 0.8-3.5 A, 4 μs, and 60 pps interacts with a single RF mode, both in a circular cavity and in a six-vane circuit by the negative mass instability. In fundamental and second-harmonic frequency generation with a circular circuit, the independently excited modes are TE11s and TE21s, with radiation power of more than 1.8 kW and an electronic efficiency of approximately 7.5%. Employing a six-vane circuit, microwave radiation of 6.0 GHz (sixth harmonic) and 3.9 GHz (fourth harmonic) is also independently generated with more than 10.4 and 4.0 kW radiation power, respectively. Corresponding electronic efficiencies are approximately 10.0 and 9.5% 相似文献
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Lee Y. H. Chung J. W. Choi Y. R. Chung J. S. Cho M. H. Namkung W. 《Plasma Chemistry and Plasma Processing》2004,24(2):137-154
NOx removal characteristics and NO conversion trends were investigated for plasma process, catalytic process, and plasma catalytic hybrid process. In the experiments, we studied effects of the flow rate and the carrier gas on the NO conversion in the plasma process, and effects of ammonia concentration and temperature on the NOx removal in the catalytic process. We also investigated the synergetic effect of a plasma-catalytic hybrid process. Dielectric barrier discharge was combined with V2O5–WO3/TiO2 catalyst for removing nitrogen oxides. The maximum conversions of nitrogen oxides were approximately 52, 80, and 98% at the temperature of 100, 200, and 300°C, respectively. The optimal energy density, ammonia concentration, and ratio of nitrogen oxides exist for the highest removal of nitrogen oxides in the plasma catalytic hybrid process. 相似文献