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( Le Quoc Bao ),( Nguyen Thi Hai ),이치환,이치환,김재홍 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
Many metal-free organic dyes have been used in DSSCs such as coumarin, merocyamine, indoline or polyene which possesses the molecular structure of the electron donor and the acceptor bridged by the conjugated chain (D-π-A). In this article, we have developed novel organic dyes in which the ullazine core was used as the π -bridge and various donor groups were added for the application of DSSCs. An aromatic, 14π-electron annulene resonance structure consisting of a centralized electron density from the inplane nitrogen provides the potential donating strength as well as electron stabilizing properties of this nitrogen-containing heterocycle. The photovoltaic performance of DSSC composed of organic chromophores were measured and evaluated by comparison with that of pristine ruthenium dye.
Bao, Le Quoc,Ho, Phuong,Chitumalla, Ramesh Kumar,Jang, Joonkyung,Thogiti, Suresh,Kim, Jae Hong Elsevier 2018 Dyes and pigments Vol.149 No.-
<P><B>Abstract</B></P> <P>A series of novel single and double branched carbazole-based red-absorbing cationic dyes without (CSI and CDI) and with (CST and CDT) a thiophene spacer have been synthesized for p-type dye-sensitized solar cells (<I>p</I>-DSSCs). The introduction of the red-absorbing cationic acceptor/thiophene spacer led to the broadening and bathochromic shift of the absorption maxima from an onset of 600 nm for CSI to 800 nm for CDT as well as improved molar absorptivity. The introduction of the double branching/thiophene spacer lowered the lowest unoccupied molecular orbital (LUMO) levels of CDI, CST, and CDT, making their potentials more positive than that of CSI. Among these, the double branched CDI exhibited the highest conversion efficiency of 0.112%. Furthermore, all of the dyes examined outperformed the standard C343 dye (0.062%), measured under similar fabrication conditions. Despite the decreased photovoltaic performance as a result of the introduction of the thiophene spacer, overall, the double branched dyes exhibited better interfacial charge transfer that led to higher J<SUB>SC</SUB> and V<SUB>OC</SUB> values compared to those of singly branched dyes. Electrochemical impedance spectroscopy analysis showed that double branched dyes have much lower charge transfer resistance and increased hole lifetime than single branched dyes. Density functional theory (DFT) and time-dependent DFT calculations were performed to theoretically characterize the optical and electrochemical properties of the synthesized dyes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Red absorbing indolium-based single and di-branched (DB) dyes were synthesized. </LI> <LI> The result shows that DB dyes exhibited higher efficiency than single branched dyes. </LI> <LI> EIS calculations indicate that DB dyes exhibit good charge transfer properties. </LI> <LI> Also showed increased hole-lifetime than single branched dyes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Doule branched dyes showed better interfacial charge transfer and hole lifetime over single branched dyes leading to enhanced photovoltaic performance.</P> <P>[DISPLAY OMISSION]</P>
Bao, Le Quoc,Phuong, Ho,Thuy, Chau Thi Thanh,Lee, Ji Won,Kim, Jae Hong,Thogiti, Suresh Informa UK (TaylorFrancis) 2017 Molecular Crystals and Liquid Crystals Vol.653 No.1
<P>Two double branched organic dyes (T1I and T2I) were synthesized, characterized, and employed as photosensitizers in p-type dye-sensitized solar cells (p-DSSC); we have compared with corresponding single branched dye (TC1) and reference dye P1. The absorbance of the dyes in solution was red shifted and the oxidation potential gradually decreased with increasing the donating ability. It was found that modification from single branched (TC1) to double branched (T1I and T2I) system resulted in increased photocurrent density leading to the higher photovoltaic performances. The charge transporting ability is increased with the introduction of double branching, as evidenced from electrochemical impedance analysis.</P>
Viet Quoc PHAM,Bao Khac Quoc NGUYEN,Thanh Quoc LE 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11
Internationalization of multinational companies in the globalized context is a popular topic in the academic world and it is also a strong concern of CEO/managers. However, this topic has not been well discussed in the academic community in Vietnam that can be contextualized in the typical transition economy. This paper is designed to explore critical success factors (CSF) of internationalization of large Vietnamese companies that have contributed major revenue from the international market. Through interviews with CEO/managers of successful companies geared toward world markets, the CSFs of internationalization have been identified and categorized into groups in which each CSF has interaction with each other, and together have combined impacts on the success of internationalization. The research results provide a conceptual framework to analyze factors affecting internationalization of large Vietnamese companies. Thank to this conceptual framework, further exploratory and/or confirmatory research can be developed to locate more success factors of internationalization. In addition, some particularly critical factors of internationalization success of Vietnamese companies are found to be useful to both CEO/ managers and policymakers. CEO/managers can benefit from the research results by concentrate their limited efforts/resources in managing these CSFs, and policymaker may design CSF-based policies to boost the internationalization of domestic companies.