Organic Solar Cells: Solution‐Processable Reduced Graphene Oxide as a Novel Alternative to PEDOT:PSS Hole Transport Layers for Highly Efficient and Stable Polymer Solar Cells (Adv. Mater. 42/2011)

Yun, Jin‐,Mun,Yeo, Jun‐,Seok,Kim, Juhwan,Jeong, Hyung‐,Gu,Kim, Dong‐,Yu,Noh, Yong‐,Jin,Kim, Seok‐,Soon,Ku, Bon‐,Cheol,Na, Seok‐,In WILEY‐VCH Verlag 2011 Advanced Materials Vol.23 No.42

<P>Solution‐processable reduced graphene oxide as a hole‐transporting layer for highly efficient and stable organic solar cells is reported on page 4923 by Dong‐Yu Kim, Seok‐In Na, and co‐workers. Introduction of a newly reduced graphene oxide by simple solution processing into solar cells dramatically raises the cell efficiency and cell life‐time. The results will allow full use of chemically reduced graphene and will advance the realization of carbon‐based printable optoelectronic devices. </P>

불안 증상을 동반한 신체화 환자의 인지적 특성

나영석,정한용,권영준,이소영,박준호 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.6

Objectives : Assuming that somatization closely interacts with anxiety symptoms, one might speculate that anxiety symptoms will produce the significant differences in development, course and treatment of somatization and the cause of these differences will be elucidated in the cognitive aspect. This study was performed to examine the cognitive characteristics in terms of the somatosensory amplification and the symptom interaction in patients with somatization accompanied by anxiety symptoms. Methods : The following measures were administered to subjects who had a T-score of >60 on somatization subscale of Symptom Checklist-90-Revision (SCL-90-R) : 1) Minnessota Multiphasic Personality Inventory-Korean Version (MMPI-K), 2) Somato-sensory Amplification Scale (SSAS), 3) Symptom Interpretation Questionnaire (SIQ). There was a comparison of differences in the somatosensory amplification and the symptom interpretation between the anxiety group and the non-anxiety group divided by T-score of >60 on the psychasthenia subscale of MMSE-K. Multiple regression analysis was performed to determine the effect of the differences in the somatosensory amplification and the symptom interpretation on age, sex, marital status and level of education between those two groups. Results : There was a greater amplification of sensation in the anxiety group than the non-anxiety group. The former showed a higher level of physical, psychological and catastrophic interpretation than non-anxiety group except with regard to environ-mental interpretation. Somatization was affected by somatosensory amplification and physical interpretation in both groups, as well as psychological interpretation in the anxiety group. Conelusion : Regarding the cognitive aspect, the somatosensory amplification and symptom interpretation were more severely distorted in patients accompanied by anxiety symptoms. These results suggest that a therapeutic approach based on the cognitive charactehstics is essential for the effective management of somatizer.

忠南 錦山郡 西臺山 一帶의 나비目 昆蟲相

남상호,조영호,장석원,박영준,이선영,나선희 대전대학교 기초과학연구소 2002 自然科學 Vol.13 No.2

충청남도 금산군 서대산 일대의 나비목 곤충상을 조사한 결과 22과 344종 1,936개체가 조사되었다. 이중 밤나방과가 102종 589개체, 자나방과가 67종 440개체로 이 2과가 전체의 50%이상을 차지하였다. 자나방과의 두줄가지나방은 1,936 개체중 85개체가 채집되어 4.4%의 가장 높은 우점도를 나타냈다. 월별 우점종은 4월 노랑무늬물결자나방, 5월 별박이세줄나비, 6월 목도리불나방, 7월 청백무늬밤나방, 8월 두줄가지나방, 9월은 털뿔가지나방이 조사되었다. 월별 종다양도는 4월 2.95, 5월 3.37, 6월 4.63, 7월 4.62, 8월 4.23, 9월은 2.97이었으며, 평균 종다양도는 3.80으로 서대산 일대의 나비목 곤충상은 비교적 양호한 편으로 조사되었다. This study was carried out to investigate Lepidopterous insect fauna from Mt. Seodae in Geumsan-gun, Chungnam. The samples were collected from April to September in 2001. Total 1,936 individuals belonging to 344 species, 22 families of Lepidoptera were collected. The sum of individuals belonging to Noctuidae and Geometridae exceed 50% of the collected samples in that Noctuidae was consisted of 102 species 589 individuals and Geometridae was 67 species 440 individuals. The dominant species in surveyed area was Rikiosatoa grisea of Geometridae, the dominant species by month were Idiotephria amelia in April, Neptis pryeri in May, Paraona staudinger in June, Ercheia niveostrigata in July, Rikiosatoa grisea in August and Alcis angulifera in September respectively. Species diversity indices by month were 2.93 in April, 3.37 in May, 4.63 in June, 4.62 in July, 4.23 in August and 2.97 in September respectively. Mean species diversity index was 3.80.

메트헤모글로빈혈증을 보인 indoxacarb 중독 1례

신재훈,이재광,박성수,나상준,박준석,Shin, Jae-Hoon,Lee, Jae-Kwang,Park, Seong-Soo,Na, Sang-Jun,Park, Joon-Seok 대한임상독성학회 2006 대한임상독성학회지 Vol.4 No.2

Acute methemoglobinemia is induced by various causes, especially ingestion of oxidizing agents such as phenazopyridine, dapsone, and nitrite. Indoxacarb is an oxadiazine insecticide with high insecticidal activity and low mammalian toxicity. It is known to block voltage-gated Na+ channels in insects and mammals, but the mechanism is not yet well understood. We describe a case of a 41-year-old woman with methemoglobinemia that developed following Indoxacarb ingestion, which improved after intravenous injection of methylene blue. This is the first known such case. If signs and symptoms of methemoglobinemia occur after Indoxacarb ingestion, antidotal therapy with methylene blue should be considered as a necessary treatment.

A CMOS-based Temperature Sensor with Subthreshold Operation for Low-voltage and Low-power On-chip Thermal Monitoring

Jun-Seok Na,Woosul Shin,Bong-Choon Kwak,Seong-Kwan Hong,Oh-Kyong Kwon 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.1

A CMOS-based temperature sensor is proposed for low-voltage and low-power on-chip thermal monitoring applications. The proposed temperature sensor converts a proportional to absolute temperature (PTAT) current to a PTAT frequency using an integrator and hysteresis comparator. In addition, it operates in the subthreshold region, allowing reduced power consumption. The proposed temperature sensor was fabricated in a standard 90 nm CMOS technology. Measurement results of the proposed temperature sensor show a temperature error of between −0.81 and +0.94°C in the temperature range of 0 to 70°C after one-point calibration at 30°C, with a temperature coefficient of 218 Hz/°C. Moreover, the measured energy of the proposed temperature sensor is 36 pJ per conversion, the lowest compared to prior works.

A CMOS-based Temperature Sensor with Subthreshold Operation for Low-voltage and Low-power On-chip Thermal Monitoring

Na, Jun-Seok,Shin, Woosul,Kwak, Bong-Choon,Hong, Seong-Kwan,Kwon, Oh-Kyong The Institute of Electronics and Information Engin 2017 Journal of semiconductor technology and science Vol.17 No.1

A CMOS-based temperature sensor is proposed for low-voltage and low-power on-chip thermal monitoring applications. The proposed temperature sensor converts a proportional to absolute temperature (PTAT) current to a PTAT frequency using an integrator and hysteresis comparator. In addition, it operates in the subthreshold region, allowing reduced power consumption. The proposed temperature sensor was fabricated in a standard 90 nm CMOS technology. Measurement results of the proposed temperature sensor show a temperature error of between -0.81 and $+0.94^{\circ}C$ in the temperature range of 0 to $70^{\circ}C$ after one-point calibration at $30^{\circ}C$, with a temperature coefficient of $218Hz/^{\circ}C$. Moreover, the measured energy of the proposed temperature sensor is 36 pJ per conversion, the lowest compared to prior works.

Pixel structures to compensate nonuniform threshold voltage and mobility of polycrystalline silicon thin-film transistors using subthreshold current for large-size active matrix organic light-emitting diode displays

Na, Jun-Seok,Kwon, Oh-Kyong IOP Publishing 2014 Japanese journal of applied physics Vol.53 No.3

<P>We propose pixel structures for large-size and high-resolution active matrix organic light-emitting diode (AMOLED) displays using a polycrystalline silicon (poly-Si) thin-film transistor (TFT) backplane. The proposed pixel structures compensate the variations of the threshold voltage and mobility of the driving TFT using the subthreshold current. The simulated results show that the emission current error of the proposed pixel structure B ranges from -2.25 to 2.02 least significant bit (LSB) when the variations of the threshold voltage and mobility of the driving TFT are +/- 0.5V and +/- 10%, respectively. (C) 2014 The Japan Society of Applied Physics</P>

Highly efficient and stable planar perovskite solar cells with reduced graphene oxide nanosheets as electrode interlayer

Yeo, Jun-Seok,Kang, Rira,Lee, Sehyun,Jeon, Ye-Jin,Myoung, NoSoung,Lee, Chang-Lyoul,Kim, Dong-Yu,Yun, Jin-Mun,Seo, You-Hyun,Kim, Seok-Soon,Na, Seok-In Elsevier 2015 Nano energy Vol.12 No.-

<P><B>Abstract</B></P> <P>We demonstrate a simple solution and room-temperature processed reduced graphene oxide (RGO) as a novel hole-transporting material (HTM) to guarantee highly efficient and highly stable CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB> perovskite solar cells (PeSCs). The effects of RGO HTM are systemically investigated in terms of PeSC efficiency, PeSC stability, morphology of perovskite film, recombination dynamics, and charge-transport through CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB>/HTM interface. The resultant PeSC with a planar configuration of glass/ITO/RGO/CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB>/PC<SUB>61</SUB>BM/bathocuproine (BCP)/Ag exhibits improved device efficiency (maximum PCE of 10.8%) with high reproducibility than those of the reference devices using conventional PEDOT:PSS and GO HTMs. Also, the RGO-based PeSCs show highly desirable device stability in comparison to the PEDOT:PSS PeSCs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly efficient and stable perovskite solar cells are developed using solution and room-temperature processed RGO. </LI> <LI> The resultant PeSC with planar architecture depicts a superior device efficiency (10.8%) to PEDOT:PSS- and GO-based solar cells. </LI> <LI> The use of RGO HTMs with the inherent passivation ability greatly extended the cell-operation time compared to PeSCs with PEDOT:PSS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Significant Vertical Phase Separation in Solvent-Vapor-Annealed Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) Composite Films Leading to Better Conductivity and Work Function for High-Performance Indium Tin Oxide-Free Optoelectronics

Yeo, Jun-Seok,Yun, Jin-Mun,Kim, Dong-Yu,Park, Sungjun,Kim, Seok-Soon,Yoon, Myung-Han,Kim, Tae-Wook,Na, Seok-In American Chemical Society 2012 ACS APPLIED MATERIALS & INTERFACES Vol.4 No.5

<P>In the present study, a novel polar-solvent vapor annealing (PSVA) was used to induce a significant structural rearrangement in poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films in order to improve their electrical conductivity and work function. The effects of polar-solvent vapor annealing on PEDOT:PSS were systematically compared with those of a conventional solvent additive method (SAM) and investigated in detail by analyzing the changes in conductivity, morphology, top and bottom surface composition, conformational PEDOT chains, and work function. The results confirmed that PSVA induces significant phase separation between excess PSS and PEDOT chains and a spontaneous formation of a highly enriched PSS layer on the top surface of the PEDOT:PSS polymer blend, which in turn leads to better 3-dimensional connections between the conducting PEDOT chains and higher work function. The resultant PSVA-treated PEDOT:PSS anode films exhibited a significantly enhanced conductivity of up to 1057 S cm<SUP>–1</SUP> and a tunable high work function of up to 5.35 eV. The PSVA-treated PEDOT:PSS films were employed as transparent anodes in polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs). The cell performances of organic optoelectronic devices with the PSVA-treated PEDOT:PSS anodes were further improved due to the significant vertical phase separation and the self-organized PSS top surface in PSVA-treated PEDOT:PSS films, which can increase the anode conductivity and work function and allow the direct formation of a functional buffer layer between the active layer and the polymeric electrode. The results of the present study will allow better use and understanding of polymeric-blend materials and will further advance the realization of high-performance indium tin oxide (ITO)-free organic electronics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2012/aamick.2012.4.issue-5/am300231v/production/images/medium/am-2012-00231v_0009.gif'></P>

대전방지 PEDOT/PSS 필름 제조를 위한 바인더에 관한 연구

김석준 ( Seok Jun Kim ),박완수 ( Wan Su Park ),황정석 ( Jung Seok Hwang ),박나영 ( Na Young Pak ),최영주 ( Young Ju Choi ),정대원 ( Dae Won Chung ) 한국공업화학회 2015 공업화학 Vol.26 No.4

It is essential to employ a binder to prepare transparent films from conductive polymer such as poly(3,4-ethylenedioxythiophene)- poly(styrene sulfonate) (PEDOT/PSS). In this paper, poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), and PSS were selected as a binder, and their effects were investigated. The formation of the film was found to be primarily dependent on the surface tension of coating solution including PEDOT/PSS and a binder. When PSS was used as a binder, the film was not formed. In case of using PVP, it was easily peeled off from the substrate. However, when using the PVA or the mixtures of PVA and PSS or PVA and PVP as a binder, films with good transparency and uniform surface resistances were produced. Based on adhesion and long-term stability tests, we concluded that the mixture of PVA and PSS is the best binder for preparing antistatic films of PEDOT/PSS.