• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.3
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• pp.151-155
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• 2014

We have developed quantum dot light emitting diodes (QD-LEDs) using a InP/ZnSe/ZnS multi-shell QD emission layer. The hybrid structure of organic hole transport layer/QD/organic electron transport layer was used for fabricating QD-LEDs. Poly(4-butylphenyl-diphenyl-amine) (poly-TPD) and tris[2,4,6-trimethyl-3-(pyridin-3-yl)phenyl]borane (3TPYMB) molecules were used as hole-transporting and electron-transporting layers, respectively. The emission, current efficiency, and driving characteristics of QD-LEDs with 50, 65 nm thick 3TPYMB layers were investigated. The QD-LED with a 50 nm thick 3TPYMB layer exhibited a maximum current efficiency of 1.3 cd/A.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.384-388
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• 1988

New methods of the reduction of carboxylic acid salts to aldehydes with 2 equiv of thexylbromoborane-dimethyl sulfide (ThxBHBr${\cdot}SMe_2$) or 9-borabicyclo[3.3.1]nonane (9-BBN) are described. Both these reagents provide the corresponding aldehydes from various as sodium and lithium salts of carboxylic acids in high yields both at room temperature. Such facile reductions are explained as the simple substitution for the bromo group of ThxBHBr by a carboxylate to form thexyl(acyloxty)borane followed by reduction with excess reagent and the formation of an ate complex followed by reduction with excess 9-BBN.

• Bulletin of the Korean Chemical Society
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• v.5 no.6
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• pp.240-244
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• 1984

8-Oxyquinoline dihydroboronite is prepared by mixing equimolar amounts of 8-hydroxyquinoline and borane-dimethyl sulfide complex in tetrahydrofuran at room temperature and its structure is determined by spectroscopic methods. The reagent is shown to be an extremely mild reducing agent and reduces aldehydes, cyclohexanones, and acid chlorides to some extent. The reagent in the presence of 0.1 equiv of boron trifluoride etherate in tetrahydrofuran at room temperature reduces selectively aldehydes in the presence of ketones, while the reagent in the presence of 1 equiv of boron trifluoride etherate rapidly reduces simple aldehydes and ketones but does not reduce carboxylic acids, esters, and amides.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.409-409
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• 2014

Recently hexagonal boron nitride (h-BN), III-V compound of boron and nitrogen with strong covalent $sp^2$ bond, is a 2 dimensional insulating material with a large direct band gap up to 6 eV. Its outstanding properties such as strong mechanical strength, high thermal conductivity, and chemical stability have been reported to be similar or superior to graphene. Because of these excellent properties, h-BN can potentially be used for variety of applications such as dielectric layer, deep UV optoelectronic device, and protective transparent substrate. Ultra flat and charge impurity-free surface of h-BN is also an ideal substrate to maintain electrical properties of 2 dimensional materials such as graphene. To synthesize a single or a few layered h-BN, chemical vapor deposition method (CVD) has been widely used by using an ammonia borane as a precursor. Ammonia borane decomposes into hydrogen (gas), monomeric aminoborane (solid), and borazine (gas) that is used for growing h-BN layer. However, very active monomeric aminoborane forms polymeric aminoborane nanoparticles that are white non-crystalline BN nanoparticles of 50~100 nm in diameter. The presence of these BN nanoparticles following the synthesis has been hampering the implementation of h-BN to various applications. Therefore, it is quite important to grow a clean and high quality h-BN layer free of BN particles without having to introduce complicated process steps. We have demonstrated a synthesis of a high quality h-BN monolayer free of BN nanoparticles in wafer-scale size of $7{\times}7cm^2$ by using CVD method incorporating a simple filter system. The measured results have shown that the filter can effectively remove BN nanoparticles by restricting them from reaching to Cu substrate. Layer thickness of about 0.48 nm measured by AFM, a Raman shift of $1,371{\sim}1,372cm^{-1}$ measured by micro Raman spectroscopy along with optical band gap of 6.06 eV estimated from UV-Vis Spectrophotometer confirm the formation of monolayer h-BN. Quantitative XPS analysis for the ratio of boron and nitrogen and CS-corrected HRTEM image of atomic resolution hexagonal lattices indicate a high quality stoichiometric h-BN. The method presented here provides a promising technique for the synthesis of high quality monolayer h-BN free of BN nanoparticles.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.399-399
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• 2012

최근 그래핀 연구와 더불어 2차원 구조의 나노소재에 대한 관심이 급증하면서 육각형의 질화붕소(hexagonal boron nitride; h-BN) 나노시트(nanosheet)[1]나 붕소 탄화질화물(boron caronitride;BCN) 나노시트[2, 3]와 같은 2차원 구조체에 대한 연구가 활발히 진행되고 있다. 그 중 BCN은 반금속(semimetal)인 흑연(graphite)과 절연체인 h-BN이 결합된 나노시트로 원소의 구성 비율에 따라 전기적 특성을 제어할 수 있다는 장점이 있다. 따라서 다양한 나노소자로의 응용을 위한 연구가 활발히 진행되고 있다. 본 연구에서는 열 화학기상증착법(thermal chemical vapor deposition)을 이용하여 폴리스틸렌(polystyrene)과 보레인 암모니아(borane ammonia)를 사용하여 BCN 나노시트를 합성하였다. 합성된 BCN 나노시트의 구조적 특징과 화학적 조성 및 결합 상태를 주사전자현미경(scanning electron microscopy), 투과전자현미경(transmission electron microscopy), X-선 광전자 분광법(X-ray photoelectron spectroscopy), 라만 분광법(Raman spectroscopy)을 통해 조사하였고, 이온성 용액법 (ionic liquid)[4]을 이용하여 전계효과 특성을 측정하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.432.2-432.2
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• 2016

A new A-D-A type (Acceptor-Donor-Acceptor) conjugated based on pyridine-borane complex (Donor), non-boron fluorine (Donor) and 2,5-bis(alkyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) (Acceptor) were designed and synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The synthesized boron based complex exhibited high electron affinity, which indicates deep HOMO energy levels and good visible absorption led to their use as donors in BHJ (bulk heterojunction) solar cells. Inverted devices were fabricated, reaching open-circuit voltage as high as 0.91eV. To probe structure-property relationship and search for design principle, we have synthesized pyridine-boron based electron donating small molecules. In this study, we report a new synthetic approach, molecular structure, charge carrier mobility and morphology of blended film and their correlation with the photovoltaic J-V characteristics in details.

• Korean Journal of Materials Research
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• v.24 no.11
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• pp.632-638
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• 2014

We investigated the effects of DMAB (Borane dimethylamine complex, C2H10BN) in electroless Ni-B film with addition of DMAB as reducing agent for electroless Ni plating. The electroless Ni-B films were formed by electroless plating of near neutral pH (pH 6.5 and pH 7) at $50^{\circ}C$. The electroless plated Ni-B films were coated on screen printed Ag pattern/PET (polyethylene terephthalate). According to the increase of DMAB (from 0 to 1 mole), the deposition rate and the grain size of electroless Ni-B film increased and the boron (B) content also increased. In crystallinity of electroless Ni-B films, an amorphization reaction was enhanced in the formation of Ni-B film with an increasing content of DMAB; the Ni-B film with < 1 B at.% had a weak fcc structure with a nano crystalline size, and the Ni-B films with > 5 B at.% had an amorphous structure. In addition, the Ni-B film was selectively grown on the printed Ag paste layer without damage to the PET surface. From this result, we concluded that formation of electroless Ni-B film is possible by a neutral process (~green process) at a low temperature of $50^{\circ}C$.

• Journal of Electrochemical Science and Technology
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• v.3 no.4
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• pp.159-164
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• 2012

Magnesium (Mg) deposition and dissolution behaviors of 0.2 M $MgBu_2-(AlCl_2Et)_2$, 0.5 M $Mg(ClO_4)_2$, and 0.4M $(PhMgCl)_2-AlCl_3$-based electrolytes with and without tris(pentafluorophenyl) borane (TPFPB) are investigated by ex situ scanning electron microscopy (SEM) and galvanostatic cycling of Mg/copper (Cu) cells. To ascertain the factors responsible for the anodic stability of the electrolytes, linear sweep voltammogrametry (LSV) experiments for various electrolytes and solvents are conducted. The effects of TPFPB as an additive on the anodic stability of 0.4M ($(PhMgCl)_2-AlCl_3$/THF electrolyte are also discussed.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.889-894
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• 2004

Polyaddition reactions of 1,1-diethynyl-3-triethylsilyl-1-silacyclopent-3-ene with several organoborane derivatives have afforded the oligomeric materials containing organosilacyclic group and organoboron moiety along the oligomer main chains. All of these materials are soluble in THF as well as chloroform, and their molecular weights are in the range of 1,990/1,190-21,950/7,050 ($M_w/M_n$) with the polydispersity indexes of 1.67-3.43. The prepared oligomers are characterized by several spectroscopic methods such as $^1H,\;^{13}C, \;^{29}Si,\;^{11}B$ NMR and FTIR spectra along with elemental analysis. FTIR spectra of all the oligomers show that the new strong C=C stretching frequencies appear at 1599-1712 $cm^{-1}$, in particular. The UV-vis absorption spectra of the materials in THF solution exhibit the strong absorption bands at the ${\lambda}_{max}$ of 268-275 nm. The oligomeric materials show that the strong excitation peaks appear at the ${\lambda}_{max}$ of 255-279 nm and the strong fluorescence emission bands at the ${\lambda}_{max}$ of 306-370 nm. All the spectroscopic data suggest that the obtained materials contain both the organoboron ${\pi}$-conjugation moiety of C=C-B-C=C and the organosilacyclic group of 3-triethylsilyl-1-silacyclopent-3-ene along the oligomer main chains. The oligomers are thermally stable up to 162-200 $^{\circ}C$ under nitrogen.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.111.2-111.2
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• 2015

Typical electrodes (metal or indium tin oxide (ITO)), which were used in conventional organic light emitting devices (OLEDs) structure, have transparency and conductivity, but, it is not suitable as the electrode of the flexible OLEDs (f-OLEDs) due to its brittle property. Although Graphene is the most well-known alternative material for conventional electrode because of present electrode properties as well as flexibility, its carrier injection barrier is comparatively high to use as electrode. In this work, we performed plasma treatment on the graphene surface and alkali metal doping in the organic materials to study for its possibility as anode and cathode, respectively. By using Ultraviolet Photoemission Spectroscopy (UPS), we investigated the interfaces of modified graphene. The plasma treatment is generated by various gas types such as O2 and Ar, to increase the work function of the graphene film. Also, for co-deposition of organic film to do alkali metal doping, we used three different organic materials which are BMPYPB (1,3-Bis(3,5-di-pyrid-3-yl-phenyl)benzene), TMPYPB (1,3,5-Tri[(3-pyridyl)-phen-3-yl]benzene), and 3TPYMB (Tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane)). They are well known for ETL materials in OLEDs. From these results, we found that graphene work function can be tuned to overcome the weakness of graphene induced carrier injection barrier, when the interface was treated with plasma (alkali metal) through the value of hole (electron) injection barrier is reduced about 1 eV.