• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.975-978
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• 2005

Electron injection in OLED organic layers is improved by using alkali metals as cathode layer or as dopants inside organic layers. An innovative alkali metal dispensing technology has been developed to overcome handling problems and to ensure controlled and reliable alkali metal layers for OLED.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.654-658
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• 1994

Rate constants have been measured spectrophotometrically for the nucleophilic substitution reactions of p-and m-nitrophenyl 2-furoates (4 and 5, respectively) with alkali metal ethoxides ($EtO^-M^+$) in absolute ethanol at 25$^{\circ}$C. The reactivity of $EtO^-M^+$ toward 4 is in the order $EtO^-K^+$ > $EtO^-Na^+$> $EtO^-Li^+$ > $EtO^-K^+$+ 18-crown-6 ether. This is further confirmed by an ion pairing treatment method. The present result indicates that (1) ion paired $EtO^-M^+$ is more reactive than dissociated $EtO^-$ ; (2) the alkali metal ions ($K^+,\;Na^+,\;Li^+$) behave as a catalyst; (3) the catalytic effect increases with increasing the size of the metal ion. A similar result has been obtained for the reaction of 5, however, the catalytic effects shown by the metal ions are more significant in the reaction of 5 than in that of 4.

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.393-398
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• 2005

The stability constants for the diaza-18-crown-6 ethers 2-6 and alkali metal cations ($Na^+,\;K^+,\;Rb^+\;and\;Cs^+$) were determined using potentiometry in 95% methanol. For each metal ion the stability constants of the partiallyfluorinated ligands 3-6 were larger than that of the non-fluorinated ligand 2, which might reflect an interaction between fluorine atoms and alkali metal cations. The stability constant of the ligand 4 was larger than that of the ligand 5 for each metal cation tested. This finding was also supported by the results of cation-induced chemical shifts in $^1H-,\;^{19}F$-NMR and extraction experiment. The potentiometry and NMR results as well as the X-ray crystal structures revealed that the position and number of fluorine atoms in the benzyl side arms was crucial for the enhanced interaction between a ligand and an alkali metal.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.48.1-48.1
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• 2010

Mono-crystalline silicon solar cell is fabricated by using alkali metals. These alkali metal, used in wet etching process, must be removed for the high efficiency solar cell. As wet etching process has been adapted due to its low cost. But lots of alkali metals like potassium remains on the silicon surface and acts as impurities. To remove these alkali metals many of cleaning process have to be applied when solar cell manufacturing process. In terms of alkali metal removal, modified etchant solution is required for concise cleaning process. In this paper ethylenediamine was used and proposed for the substituion of postassium hydroxide.

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.93-97
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• 1991

Rate constants have been measured spectrophotometrically for the reactions of alkali metal ethoxides with 4-nitrophenyl benzoate, S-4-nitrophenyl thiobenzoate and 4-nitrophenyl thionbenzoate in ethanol at 25$^{\circ}$C. Substitution of S for O in the leaving group has not affected reactivity significantly, while the effect of the similar replacement in the acyl group has led to rate decrease by a factor of 10, although pronounced rate enhancements have been expected for both systems. The replacement of O by a polarizable S has also influenced the reactivity of the esters toward alkali metal ethoxides, i.e. the reactivity decreases as the size of the metal ion decreases. The alkali metal ions have showed inhibition effect instead of catalytic effect which would have been expected for the present system. The effect of replaced sulfur atom on the reactivity for the present system is attributed to the nature of hard and soft acids and bases.

• Journal of Photoscience
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• v.11 no.32
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• pp.83-87
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• 2004

A porphyrin compound containing a crown ether moiety (Por-Crown) and its zinc complex (ZnPor-Crown) have been prepared and the effect of the addition of alkali metal on their fluorescence has been investigated. As alkali metal cations were added, the absorption and fluorescence maxima did not change. However, the absorbance and intensity of fluorescence increased dramatically. Among the alkali metal cations tested, addition of K$^{+}$ and Cs$^{+}$ showed strongest enhancement of absorbance and fluorescence intensity of Por-Crown and ZnPor-Crown.own.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.883-888
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• 2001

We describe an ion-surface scattering apparatus newly developed to investigate the reactive scattering process of low-energy alkali-metal ions at surfaces. The apparatus consists of an alkali-metal ion gun that is rotatable by 360°, a quadrupole mass spectrometer (QMS) with an ion energy analyzer, a sample manipulator with a heating-and-cooling stage, and an ultrahigh vacuum (UHV) chamber that houses these components. Preliminary experimental results obtained from the apparatus are presented on angular and energy distributions of the ions scattered from clean Pt(111) and water-adsorbed Pt surfaces.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.1996-2000
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• 2009

Alkali metal salts were introduced to enhance the ionization efficiency of glucose and maltooligoses in electrospray ionization-mass spectrometry (ESI-MS). A mixture of the same moles of glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose was used. Salts of lithium, sodium, potassium, and cesium were employed as the cationizing agent. The ionization efficiency varied with the alkali metal cation types as well as the analyte sizes. Ion abundance distribution of the [M+$cation]^+$ ions of the carbohydrates varied with the fragmentor voltage. The maximum ion abundance at low fragmentor voltage was observed at maltose, while the maximum ion abundance at high fragmentor voltage shifted to maltotriose or maltotetraose for Na, K, and Cs. Variation of the ionization efficiency was explained with the hydrated cation size and the binding energy of the analyte and alkali metal cation.

• Textile Coloration and Finishing
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• v.6 no.4
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• pp.72-76
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• 1994

The permselectivity of alkali metal chlorides through silk fibroin membrane was investigated at $25^{\circ}C$: The Permeability coefficients were found to increase in a sequence of LiCl < NaCl < KCl < CsCl. This sequence was explained by considering the partition and the hydrophilic membrane. The dependence of the permeability on the salts concentration was interpreted by means of TMS theory. The ionic mobility ratio of alkali metal chlorides through this membrane decreased with the increase of the Stokes radius. The Effectiveness of the charged density was found to depend on the ionic species. The greater the Stokes radius the larger the effective charge density of membrane.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.541-545
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• 2008

Stable molecular isomers were calculated for the azobenzene crown ether p-tert-butylcalix[4]arene (1) in the host and their alkali-metal-ion complexes. The structures of two distinct isomers (cis and trans) have been optimized using DFT B3LYP/6-31G(d,p) method. Trans isomer of 1 is found to be 11.69 kcal/mol more stable than cis analogue. For two different kinds of complexation mode, the alkali-metal-cation in the crown-ether moiety (exo) has much better complexation efficiency than in the benzene-rings (endo) pocket for both isomers of 1. Sodium ion has much better complexation efficiency than potassium ion in all kinds of complexation mode with host 1. The Na+ complexation efficiency of the trans-complex (1) in the exo-binding mode is 8.24 kcal/mol better than cis-exo analogue.