Electron beam sintering at ambient pressure is demonstrated for the first time, in formation of highly conductive silver patterns composed of silver nanoparticles. Silver nanoparticles were inkjet printed on a plastic substrate, followed by rapid ebeam irradn., without causing any damage to the substrate. It was found that exposing the printed silver patterns to a dose of 600 kGy yielded a resistivity as low as 4.5 μΩ cm, which is only 2.8 times higher than that of the bulk silver. The effect of various parameters related to electron energy and penetration depth on the sintering efficiency was evaluated. This finding reveals the applicability of ebeam technol. in printed electronics for large-scale, roll-to-roll, high throughput printing processes. [on SciFinder(R)]

As a reversible thermochromic material, V dioxide (VO2) is a promising candidate for smart window applications. The trade-off between the integrated visible transmission (Tlum) and the solar modulating ability (ΔTsol), as well as the high phase transition temp. (τc∼68°) are regarded as the main obstacle for practical applications of pure VO2 nanomaterials. The combination of both high τc reducing efficiency of W and improving Tlum/ΔTsol properties of RE (rare earth: Eu, Tb), herein lies the purpose of RE/W-codoping to enhance the thermochromic performance. The RE/W-codoped VO2 nanoparticles were synthesized under hydrothermal conditions, and exhibited grain size of <100 nm. The smart window which was fabricated by coating RE/W-codoped VO2 nanoparticles onto glass, exhibits a thermochromic performance with a combination Tlum = 40%, ΔTsol = 6.3%, τc = 40.8° or Tlum = 63%, ΔTsol = 3.6%, τc = 31.9°, indicating the largely reduced absorption compared with the single W doping. Under the RE/W-codoping conditions, the ionic radius of the RE3+ cations controlled the crystallinity of the VO2 particles and the electron/hole carrier counteraction as well as the competition between the strain and the hole carrier played a vital role in modulating the τc of the VO2 products. The findings should be meaningful for studying the codoping mechanisms for VO2 nanomaterials. [on SciFinder(R)]

Potassium (K) post-treatment on CIGSSe has been shown to yield the highest efficiency reported to date. However, very little is known on the effect of K doping in CZTSSe and the mechanism behind the efficiency improvement. Here we reveal the mechanism by which K enhances the charge sepn. in CZTSSe. We show that K accumulates at the CdS/CZTSSe, passivating the recombination at the front interface and improving carrier collection. K is also found to accumulate at the CZTSSe/Mo interface and facilitates the diffusion of Cd into the absorber which affects the morphol. and grain growth of CZTSSe. As revealed by the C-V, external quantum efficiency, and color J-V test, K doping significantly increases the carrier d., improves carrier collection, and passivates the front interface and grain boundaries, leading to the enhancement of Voc and Jsc. The av. power conversion efficiency has been promoted from 5% to above 7%, and the best 7.78% efficiency has been achieved for the 1.5 mol % K-doped CZTSSe device. This work offers some new insights into the K doping effects on CZTSSe via soln.-based approach and demonstrates the potential of facile control of K doping for further improvement of CZTSSe thin film solar cells. [on SciFinder(R)]

Printing conducting copper interconnections on plastic substrates is of growing interest in the field of printed electronics. Photonic curing of copper inks with intense pulsed light (IPL) is a promising process as it is very fast, and so can be incorporated in roll-to-roll prodn. We report on using IPL for obtaining conductive patterns from inks composed of submicron particles of copper formate, a copper precursor that has a self-redn. property. Decompn. of copper formate can be performed by IPL, and is affected both by the mode of energy application and the properties of the printed precursor layer. The energy application mode was controlled by altering three pulse parameters: duration, intensity, and repetitions at 1 Hz. Since the decompn. results from energy transfer via light absorption, carbon nanotubes (CNTs) were added to the ink to increase the absorbance. We show that there is a strict set of IPL parameters necessary to obtain conductive copper patterns. Finally we show that by adding as little as 0.5 wt.% SWCNTs to the ink, the absorptance was enhanced by about 50%, and the threshold energy required to obtain a conductive pattern decreased by ∼25%. These results have major implications for tailoring inks intended for IPL processing. [on SciFinder(R)]

The occurrence of pesticidal pollution in the environment and the resistance in the mosquito species makes an urge for the safer and an effective pesticide. Permethrin, a poorly water-soluble pyrethroid pesticide, was formulated into a hydrodispersible nanopowder through rapid solvent evaporation of pesticide-loaded oil in water microemulsion. Stability studies confirmed that the nanopermethrin dispersion was stable in paddy field water for 5 days with the mean particle sizes of 175.3 ± 0.75 nm and zeta potential of -30.6 ± 0.62 mV. The instability rate of the nanopermethrin particles was greater in alkaline (pH 10) medium when compared with the neutral (pH 7) and acidic (pH 4) dispersion medium. The colloidal dispersion at 45°C was found to be less stable compared with the dispersions at 25 and 5°C. The 12- and 24-h lethal indices (LC50) for nanopermethrin were found to be 0.057 and 0.014 mg l-1, respectively. These results were corroborative with the severity of damages observed in the mosquito larvae manifested in epithelial cells and the evacuation of the midgut contents. Further, the results were substantiated by the decrease in cellular biomolecules and biomarker enzyme activity in nanopermethrin treated larvae when compared to bulk and control treatment.[on SciFinder (R)]

An appealing alternative approach to the conventional electrochem. deposition is presented, which can be universally utilized to form nanomaterial coatings from their aq. dispersions without involving their oxidn.-redn. It is based on altering the ionic strength by elec. potential in the vicinity of the electrode surface, which causes the nanomaterials to deposit. The concept has been demonstrated for four different systems. [on SciFinder(R)]