Highly efficient white light with sharp red–green–blue emissions from iridium complexes doped carbazole-grafted poly(para-phenylene)

We demonstrated a high-efficiency white polymer light-emitting diode (WPLED) based on carbazole-grafted poly(para-phenylene) (CzPPP) doped with green- and red-emitting Ir complexes as the emitting layer. The device exhibits pure white light yet with stable sharp blue (430 nm), green (512 nm), and red (613 nm) emissions and has the maximum current and external quantum efficiencies of 16.8 cd/A and 8.65%, respectively. The overall performance is resulted from the excellent shielding effect of CzPPP host to prevent back transfer of triplet energy especially from the green phosphor.     

Photovoltaic devices based on a novel poly(phenylene ethynylene) derivative

A novel poly(phenylene ethynylene) derivative containing benzothiadiazole (BT) co-monomer (PPE-BT) was synthesized, characterized and used for photovoltaic devices. Photovoltaic devices of ITO/PEDOT-PSS/pristine PPE-BT/Ba/Al and ITO/PEDOT-PSS/PPE-BT+PCBM (1/4 w/w)/Ba/Al were fabricated and their photovoltaic performances were measured and discussed. The energy conversion efficiency and incident photo-current conversion efficiency of photovoltaic device based on PPE-BT+PCBM reached 0.022% (78.2 mW/cm², AM1.5) and 1% (391 nm), respectively. Its photosensitivity reached 3.1 mA/W, which is almost one order of magnitude higher compared to that of the pure PPE-BT. The electroluminescence of pristine PPE-BT was almost completely quenched when it was blended with PCBM.     

Photocurrent spectral responses in poly (2,5-dimethoxy-p-phenylenevinylene) devices

We report the spectral response of the photocurrent in the sandwich configuration of poly (2,5-dimethoxy-p-phenylenevinylene) (DMPPV) devices. The photocurrent spectral responses are dependent on the polarity of the illuminated surface and the electrodes. The polarity-dependent photocurrent is modeled on a basis where charge carrier drift plays a dominant mechanism and hole transport is predominant over electron transport. The model can explain the results for the Au/DMPPV/Au symmetric configuration. The model cannot however explain the results for the indium-tin oxide (ITO)/DMPPV/Al device. The response for the light incident on the Al side is also reported. The spectral dependence is also studied as a function of bias electric field. Mechanisms leading to the behavior of the photocurrent spectral dependence are speculated.     

Soldering with a focused light beam (review)

The results of scientific investigations are summarized and the examples of practical application of the focused light beam of arc xenon lamps for soldering various components are described.     

Dispersion of concentrated aqueous neodymia-yttria-alumina mixture with ammonium poly(acrylic acid) as dispersant

A stable aqueous slurry using ammonium polyacrylic acid polyelectrolyte as dispersant and a neodymia-yttria-alumina mixture was prepared as the starting powder. The effect of the polyelectrolyte concentration and the pH of the slurry on the stability of the suspension is studied, and the optimal pH value and the amount of dispersant needed to obtain a stable slurry were determined. Highly consistent slurries with optimal pH and dispersant concentration were prepared by ball milling. The rheological behavior of the slip with different solid loading (48-58 wt.%) has been studied by measuring the viscosity and shear stress as a function of shear rate. Slip with solid loadings of 53 wt.% shows near-Newtonian behavior but becomes non-Newtonian with typical shear-thinning behavior above this solid loading value. The density and microstructure of the cast product bears a direct relationship to the state of the slip induced by variation of the pH and the concentration of the dispersant as well as by solid loading. Transparent Nd:YAG ceramics were obtained by sintering of compacts prepared from optimized slurries at 1750 °C in vacuum.     

Extraction of palladium （Ⅱ） from hydrochloride solutions with 2-n-octyl-4-isothiazolin-3-one as novel extractant

Solvent extraction of palladium （Ⅱ） from hydrochloric acid solution with 2-n-octyl-4-isothiazolin-3-one （OIT）/cyclohexane was studied. Effects of different parameters on extraction efficiency were evaluated. 99.96 % and 98.26 % palladium （Ⅱ） could be effectively extracted with 0.018 mol·L^-1 OIT/cyclohexane of 0.1 and 4.0 mol·L^-1 HCl medium, respectively. Nonpolar solvent and low acidity could improve the extracting efficiency, and successfully strip palladium （Ⅱ） from the loaded organic phase was achieved with 0.5 mol·L^-1 （NH2）2CS solution. It was proposed that the extraction of Pd com-plexes from HCl medium proceeded through the ion-association mechanism by slope method, NMR and FF-IR spectra.