Rapid Typing of Clinical Strains of Mycobacterium tuberculosis by IS6110-based Outward PCR

이혜영,--,--,--,--,-- THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 2004 Journal of biomedical laboratory sciences Vol.10 No.2

Worldwide, tuberculosis remains one of the leading infectious diseases, accounting for nearly 3 million deaths and more than 8 million new cases annually. DNA typing of Mycobacterium tuberculosis is important for the control of tuberculosis, since it can be used to track transmission route of tuberculosis, source of internal laboratory contaminations, and to answer questions on the nature of tuberculosis infections such as reactivation or exogenous reinfection of disease. At present, IS6110-based RFLP is the choice of method for typing large numbers of clinical isolates of M. tuberculosis, since it has the highest resolution power. However, RFLP requires long time, high cost and qualified experts, so only reference level laboratories can use the RFLP technique. In order to have an optional molecular typing method suitable for the clinical settings, this study evaluated the use of one of PCR-based typing methods, IS6110-based outward PCR for typing clinical isolates of M. tuberculosis. In brief, the results from this study showed that IS6110-based RFLP is useful to discriminate diverse clinical isolates of M. tuberculosis as well as to identify clinical isolates that belong to the same family or cluster groups that have been previously classified by RFLP analysis. In addition, the banding profiles resulted from IS6110-based outward PCR seemed to represent genomic characteristics of M. tuberculosis, since strains belong to the K-family generated unique band that is not present in any other strains but present only in the genome of K-family strains. The IS6110-based outward PCR was also shown to be useful with DNAs isolated directly from liquid cultures indicating this method can be suitable for typing M. tuberculosis in clinical settings.

Low-Temperature Modification of ZnO Nanoparticles Film for Electron-Transport Layers in Perovskite Solar Cells

Han, Gill Sang,Shim, Hyun-Woo,Lee, Seongha,Duff, Matthew L.,Lee, Jung-Kun Wiley (John WileySons) 2017 ChemSusChem Vol.10 No.11

Multi-functional transparent electrode for reliable flexible perovskite solar cells

Han, Gill Sang,Lee, Seongha,Duff, Matthew Lawrence,Qin, Fen,Jiang, Minlin,Li, Guangyong,Lee, Jung-Kun Elsevier 2019 Journal of Power Sources Vol.435 No.-

<P><B>Abstract</B></P> <P>Multilayer MoO<SUB>x</SUB>/Ag/MoO<SUB>x</SUB> (DMD) films are found to be transparent conducting electrodes for use in extremely stable and highly bendable flexible perovskite solar cells (PSCs). The optical transparency and electric properties of DMD and its role as a top electrode of PSCs were studied by changing the thickness of the MoO<SUB>x</SUB> layer. Although the MoO<SUB>x</SUB> thickness was shown to have a negligible effect on the sheet resistance of DMD, the transmittance of visible light, selective carrier transport capability, and long-term stability of a device considerably depend on this factor. The sandwich structure of a 20-nm-thick MoO<SUB>x</SUB>, 7-nm-thick Ag, and 20-nm-thick MoO<SUB>x</SUB> exhibits a high transmittance and large photon–electron conversion rate of PSCs. In addition, PSCs using the DMD top electrode maintain 92% of their initial current density after 24 h of continuous operation owing to a UV light cut-off of the top illumination. Moreover, the overall structure of DMD blocks the diffusion of water and oxygen molecules from real environmental conditions. At the same time, the underlying/upper MoO<SUB>x</SUB> layer retards the degradation through a chemical reaction between Ag and the halide ions inside the cells, as well as foreign ions from outside the polluted atmosphere. When DMD is applied to flexible PSCs on Ti foil, the PCE reaches 14.5%, and mechanical integrity of the PSCs is maintained at a bending radius of 4 mm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MoO<SUB>x</SUB>/Ag/MoO<SUB>x</SUB> multilayer is used as a top electrode of perovskite solar cells. </LI> <LI> The multilayer electrode has multiple functions in real operation environment. </LI> <LI> 92% of the initial current density is maintained after 24 h continuous operation. </LI> <LI> The efficiency of flexible solar cells using MoO<SUB>x</SUB>/Ag/MoO<SUB>x</SUB> reaches 14.5%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Epitaxial Anatase TiO₂ Nanorods Array with Reduced Interfacial Charge Recombination for Solar Water Splitting

Han, Gill Sang,Lee, Sangwook,Yu, Eun Sang,Park, Sung Pyo,Cho, In Sun,Jung, Hyun Suk Electrochemical Society 2016 Journal of the Electrochemical Society Vol.163 No.6

<P>We report an epitaxial growth of anatase TiO2 nanorods array (ANRs) on a niobium-doped TiO2 (NTO)/SrTiO3 (STO) single crystal substrate and its impact on charge transport and collection properties for photoelectrochemical (PEC) water splitting. The NTO film (similar to 6 at.% of Nb) with a thickness of similar to 250 nm, was initially deposited as a transparent conducting electrode on a STO single crystal substrate by pulsed laser deposition. Subsequently, the anatase TiO2 nanorods array, with an average length of similar to 200 nm, was grown on the NTO/STO substrate by a two-step hydrothermal method. Epitaxial relationship between the TiO2 nanorods and the substrate was investigated by X-ray diffraction and transmission electron microscopic analysis. From impedance spectroscopy measurements, we found that the resistance of the ANRs is much lower than that of anatase TiO2 nanoparticle-based films, which originates from the single crystalline nature of the ANRs and lower interfacial resistance due to epitaxial growth. For PEC water splitting, the lower bulk and interfacial resistance of the ANRs facilitates better charge transport and collection, thereby improving the photocurrent density and rate of hydrogen evolution. (C) 2016 The Electrochemical Society. All rights reserved.</P>

Highly stable perovskite solar cells in humid and hot environment

Han, Gill Sang,Yoo, Jin Sun,Yu, Fangda,Duff, Matthew Lawrence,Kang, Bong Kyun,Lee, Jung-Kun Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.28

<P>An organic-inorganic perovskite solar cell (PSC) is a very promising candidate for a next-generation photovoltaic system. For the last three years, the power conversion efficiency (PCE) of PSCs has been dramatically improved from 9.7% to 22.1%; however, a poor long-term stability still limits the commercialization of PSCs. In this study, we explore the effect of poly(methyl methacrylate) (PMMA)/reduced graphene oxide (rGO) composite (PRC) passivation layer on the chemical and thermal stability of PSCs. The PRC passivation layer shows superior protection performance due to improved hydrophobicity and increased complexity of the O2or H2O diffusion pathway. Moreover, the excellent thermal conductivity of rGO facilitates heat dissipation through the PRC layer. When the PRC layer is coated, the aging of PSCs is significantly prevented even under extreme conditions of humidity (>75%) and temperature (∼85 °C). Consequently, the PCE of PRC-passivated PSCs exhibits a negligible change in air, temperature of 35 °C, and humidity of 40% for 1000 h. Our study offers a simple and robust way to fabricate long-term stable and highly efficient PSCs, thus providing a path to PSC commercialization.</P>

Correlation between photoactivity of TiO₂ and diffusion of Na⁺ ions from soda lime glass

Han, Gill Sang,Yun, Yeonghun,Kim, Min Hee,Han, Se-Hoon,Jung, Hyun Suk,Lee, Sangwook Elsevier 2018 Materials letters Vol.228 No.-

<P><B>Abstract</B></P> <P>In this study, we report the effects of Na<SUP>+</SUP> diffusion into TiO<SUB>2</SUB> during thermal annealing on TiO<SUB>2</SUB> photocatalysis. After annealing at 500 °C for 1 h, the photoactivity of colloidal sol-based crystalline TiO<SUB>2</SUB> is almost similar regardless of substrates. Interestingly, after the annealing the photoactivity of polymeric sol-based amorphous TiO<SUB>2</SUB> thin film on soda lime glass (SLG) is significantly reduced compared to that on quartz. We observed that Na<SUP>+</SUP> does not easily bond with TiOTi in crystalline TiO<SUB>2</SUB>, while large amount of TiONa bonds are formed in the amorphous TiO<SUB>2</SUB> on SLG during crystallization at 500 °C. Our results suggest that the control of TiO<SUB>2</SUB> photoactivity has applications in improving photo-stability of various optoelectronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Crystalline TiO<SUB>2</SUB> on SLG exhibits similar photoactivity with that on quartz, after annealing. </LI> <LI> Amorphous TiO<SUB>2</SUB> on SLG exhibits lower photoactivity than that on quartz, after annealing. </LI> <LI> Na<SUP>+</SUP> does not easily bond with TiOTi in crystalline TiO<SUB>2</SUB>. </LI> <LI> TiONa bonds are formed in amorphous TiO<SUB>2</SUB> on SLG during crystallization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Retarding charge recombination in perovskite solar cells using ultrathin MgO-coated TiO₂ nanoparticulate films

Han, Gill Sang,Chung, Hyun Suk,Kim, Byeong Jo,Kim, Dong Hoe,Lee, Jin Wook,Swain, Bhabani Sankar,Mahmood, Khalid,Yoo, Jin Sun,Park, Nam-Gyu,Lee, Jung Heon,Jung, Hyun Suk The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.17

<▼1><P>MgO ultrathin nanolayers are able to efficiently retard charge recombination in perovskite solar cells.</P></▼1><▼2><P>MgO-coated TiO2 nanoparticle (NP)-based electron collecting layers were fabricated to prevent charge recombination at the methylamine lead iodide/TiO2 interface in perovskite solar cells. The open circuit voltage (<I>V</I>oc) and fill factor (ff) of perovskite solar cells based on MgO-coated TiO2 charge collectors were 0.89 V and 71.2%, respectively. These values were 4.7% and 6.1% higher than the pure TiO2 based perovskite solar cells. Transient photovoltage decay data exhibited recombination times for MgO-coated TiO2 NP-based perovskite solar cells about three times longer than those of TiO2 NP based solar cells. The longer recombination time was responsible for enhancing the <I>V</I>oc and ff of MgO-coated TiO2 NP-based perovskite solar cells. By employing a MgO nanolayer, we observed that the power conversion efficiency (PCE) was increased from 11.4% to 12.7%, demonstrating that MgO ultrathin nanolayers are able to efficiently retard charge recombination in perovskite solar cells.</P></▼2>

Highly Bendable Flexible Perovskite Solar Cells on a Nanoscale Surface Oxide Layer of Titanium Metal Plates

Han, Gill Sang,Lee, Seongha,Duff, Matthew Lawrence,Qin, Fen,Lee, Jung-Kun American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.5

<P>We report highly bendable and efficient perovskite solar cells (PSCs) that use thermally oxidized layer of Ti metal plate as an electron transport layer (ETL). The power conversion efficiency (PCE) of flexible PSCs reaches 14.9% with a short-circuit current density (<I>J</I><SUB>sc</SUB>) of 17.9 mA/cm<SUP>2</SUP>, open-circuit voltage (<I>V</I><SUB>oc</SUB>) of 1.09, and fill factor (ff) of 0.74. Moreover, the Ti metal-based PSCs exhibit a superior fatigue resistance over indium tin oxide/poly(ethylene terephthalate) substrate. Flexible PSCs maintain 100% of their initial PCE even after PSCs are bent 1000 times at a bending radius of 4 mm. This excellent performance of flexible PSCs is due to high crystalline quality and low oxygen vacancy concentration of TiO<SUB>2</SUB> layer. The concentration of oxygen vacancies in the oxidized Ti metal surface controls the electric function of TiO<SUB>2</SUB> as ETL of PSCs. A decrease in the oxygen vacancy concentration of the TiO<SUB>2</SUB> layer is critical to improving the electron collection efficiency of the ETL. Our results suggest that Ti metal-based PSCs possess excellent mechanical properties, which can be applied to the renewable energy source for flexible electronics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2018/aamick.2018.10.issue-5/acsami.7b16499/production/images/medium/am-2017-16499z_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am7b16499'>ACS Electronic Supporting Info</A></P>

Reduced Graphene Oxide/Mesoporous TiO₂ Nanocomposite Based Perovskite Solar Cells

Han, Gill Sang,Song, Young Hyun,Jin, Young Un,Lee, Jin-Wook,Park, Nam-Gyu,Kang, Bong Kyun,Lee, Jung-Kun,Cho, In Sun,Yoon, Dae Ho,Jung, Hyun Suk American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.42

<P>We report on reduced graphene oxide (rGO)/mesoporous (mp)-TiO<SUB>2</SUB> nanocomposite based mesostructured perovskite solar cells that show an improved electron transport property owing to the reduced interfacial resistance. The amount of rGO added to the TiO<SUB>2</SUB> nanoparticles electron transport layer was optimized, and their impacts on film resistivity, electron diffusion, recombination time, and photovoltaic performance were investigated. The rGO/mp-TiO<SUB>2</SUB> nanocomposite film reduces interfacial resistance when compared to the mp-TiO<SUB>2</SUB> film, and hence, it improves charge collection efficiency. This effect significantly increases the short circuit current density and open circuit voltage. The rGO/mp-TiO<SUB>2</SUB> nanocomposite film with an optimal rGO content of 0.4 vol % shows 18% higher photon conversion efficiency compared with the TiO<SUB>2</SUB> nanoparticles based perovskite solar cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-42/acsami.5b06171/production/images/medium/am-2015-06171k_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b06171'>ACS Electronic Supporting Info</A></P>

Enhanced Light Harvesting by Fast Charge Collection Using the ITO Nanowire Arrays in Solid State Dye-sensitized Solar Cells

Gill Sang Han,Jin Sun Yu,Hyun Suk Jung 한국진공학회 2014 한국진공학회 학술발표회초록집 Vol.2014 No.2