New Hybrid Hole Extraction Layer of Perovskite Solar Cells with a Planar p–i–n Geometry

Park, Ik Jae,Park, Min Ah,Kim, Dong Hoe,Park, Gyeong Do,Kim, Byeong Jo,Son, Hae Jung,Ko, Min Jae,Lee, Doh-Kwon,Park, Taiho,Shin, Hyunjung,Park, Nam-Gyu,Jung, Hyun Suk,Kim, Jin Young American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.49

<P>We report a highly efficient p–i–n type planar perovskite solar cell with a hybrid PEDOT/NiO<SUB><I>x</I></SUB> hole-extraction layer. It has been found that the perovskite solar cell with a NiO<SUB><I>x</I></SUB> thin film as a hole-extraction layer generally exhibits lower fill factor compared to the conventionally used PEDOT:PSS thin film, whereas it shows higher photocurrent and photovoltage. The fill factor of the NiO<SUB><I>x</I></SUB>-based perovskite solar cell can be significantly improved by treating the NiO<SUB><I>x</I></SUB> surface with a dilute PEDOT solution. The photoluminescence quenching study and impedance spectroscopic (IS) analysis have revealed that the hole injection at the perovskite/NiO<SUB><I>x</I></SUB> interface is significantly facilitated with the PEDOT treatment, which should lead to the increased fill factor. As a result, the p–i–n type planar perovskite solar cell with the new hybrid hole-extraction layer exhibits a high conversion efficiency of 15.1% without the hysteresis effect.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-49/acs.jpcc.5b09322/production/images/medium/jp-2015-093225_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b09322'>ACS Electronic Supporting Info</A></P>

간호대학생의 문화적 역량과 문화 간 의사소통 관계

유현정(Yoo, Hyunjung),김관희(Kim, Kwanhee),이하정(Lee, Hajeong),박보미(Park, Bomi),박수빈(Park, Subin),박주희(Park, Juhui),박진희(Park, Jinhui),반민주(Ban, Minjoo),임지현(Lim, Jihyun),박준후(Park, Junhoo),이예은(Lee, Yee Eun) 한국농촌간호학회 2019 한국농촌간호학회지 Vol.14 No.2

Purpose: This study was done to identify the cultural capacity of college nursing students and the relationship of intercultural communication. Methods: The participants were 200 students in colleges of nursing from 6 universities in C city, who understood the purpose of the study and agreed to participate. Collected data were analyzed with t-test, ANOVA, correlation analysis, and stepwise regression analysis using SPSS/WIN 22.0. Results: Cultural sensitivities in this study (r=.372, p<.001), cultural knowledge (r=.399, p=.001), cultural awareness (r=.547, p<.001), and cultural technology (r=.550, p<.001) each showed a statistically significant correlation with intercultural communication skills. Conclusion: The results of this study show that reinforcement of the cultural and intercultural communication ability of college nursing students, in-depth exploration of the cultural area and religious inspection, cultural and professional backgrounds, assessment and consideration of cultural characteristics, nursing diagnosis, and health appropriate to the cultural background. It is suggested that education such as service provision should be conducted systematically.

A Folksonomy Ranking Framework : A Semantic Graph-based Approach

Hyunjung Park,Sangkyu Rho 한국경영정보학회 2011 Asia Pacific Journal of Information Systems Vol.21 No.2

Understanding of the Role of Polysilicon Layer in Passivating Contact Solar Cells

HyunJung Park(박현정),Se Jin Park(박세진),Soohyun Bae(배수현),Ji Yeon Hyun(현지연),Chang Hyun Lee(이창현),Dongjin Choi(최동진),Dongkyun Kang(강동균),Hyebin Han(한혜빈),Yoonmook Kang(강윤묵),Hae-Seok Lee(이해석),Donghwan Kim(김동환) 한국신재생에너지학회 2019 한국신재생에너지학회 학술대회논문집 Vol.2019 No.11

DEMOGRAPHIC AND SOCIOECONOMIC CHARACTERISTICS OF KOREAN AMERICANSIN THE UNITED STATES IN 1980

HYUNJUNG PARK 서울대학교 사회발전연구소 1990 Journal of Asian Sociology Vol.19 No.2

DEMOGRAPHIC AND SOCIOECONOMIC CHARACTERISTICS OF KOREAN AMERICANS IN THE UNITED STATES IN 1980

PARK, HYUNJUNG The Population and Development Studies Center Seou 1990 Korea Journal of Population and Development Vol.19 No.2

Based on the analysis of 1980 Public-Use Microdata Samples, this article demonstrates that the Korean immigrant stream, particularly men, has been very selective even before the 1965 reform due mainly to the restrictive U.S. immigration policies, although the significant presence of Korean Americans came after the influx of the post 1965-immigrants, known as a highly selected group. This selectivity is best represented in their high educational profile. However, despite the educational superiority and somewhat positive occupational position, Korean men in the U.S. are seriously disadvantaged in income regardless of nativity status. Korean Americans are not as successful as whites in translating their education into occupation and income; they are better educated for the same job, but experience a lower income return to the same education and the same occupation.

A survey on education needs of the death preparation in hemodialysis nurses

Hyunjung Park,Sisook Kim 한국간호과학회 2023 한국간호과학회 학술대회 Vol.2023 No.11

High capacity monoclinic Nb₂O₅ and semiconducting NbO₂ composite as high-power anode material for Li-Ion batteries

Park, Hyunjung,Lee, Dongsoo,Song, Taeseup Elsevier 2019 Journal of Power Sources Vol.414 No.-

<P><B>Abstract</B></P> <P>Niobium pentoxide, Nb<SUB>2</SUB>O<SUB>5</SUB>, is an intercalation-type material with a high theoretical capacity of ∼404 mAh g<SUP>−1</SUP> for Li-ion batteries. However, electrochemical properties of Nb<SUB>2</SUB>O<SUB>5</SUB> largely depend on its various polymorphs with different crystal structures, and their low electrical conductivity acts as the main obstacle. Here, we report high-temperature calcined monoclinic Nb<SUB>2</SUB>O<SUB>5</SUB> and semiconducting NbO<SUB>2</SUB> composite as a high-power anode material. Monoclinic Nb<SUB>2</SUB>O<SUB>5</SUB> itself as a main active material shows a high capacity of ∼280 mAh g<SUP>−1</SUP>, and NbO<SUB>2</SUB> with a small band gap of ∼0.5 eV not only improves electrical conductivity but also gives a capacity of ∼110 mAh g<SUP>−1</SUP>. To have a synergic effect of these two materials, the Nb<SUB>2</SUB>O<SUB>5</SUB>/NbO<SUB>2</SUB> composite is prepared <I>via</I> simple post-calcination of as-prepared Nb<SUB>2</SUB>O<SUB>5</SUB> under a reduction atmosphere. It shows a discharge capacity of ∼214 mAh g<SUP>−1</SUP> at 0.05 C, a high initial Coulombic efficiency of 94.7%, a superior rate capability of ∼40 mAh g<SUP>−1</SUP> at 100 C, and a robust cycle performance of 81% retention over 900 cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Monoclinic Nb<SUB>2</SUB>O<SUB>5</SUB> was prepared by high calcination at 1100 °C. </LI> <LI> Semi-conducting NbO<SUB>2</SUB> was introduced to Nb<SUB>2</SUB>O<SUB>5</SUB> by thermal reduction process. </LI> <LI> Nb<SUB>2</SUB>O<SUB>5</SUB>/NbO<SUB>2</SUB> composite shows a cycle performance of 81% retention over 900 cycles. </LI> <LI> Nb<SUB>2</SUB>O<SUB>5</SUB>/NbO<SUB>2</SUB> composite shows a superior rate capability at 100C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis of Carboxymethyl Cellulose Lithium by Weak Acid Treatment and Its Application in High Energy-Density Graphite Anode for Li-Ion Batteries

Park, Hyunjung,Lee, Dongsoo,Song, Taeseup American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.27

<P>Carboxymethyl cellulose lithium (CMC-Li) has recently been explored as a promising binder for Li-ion batteries because of enhanced Li<SUP>+</SUP> ion flux. CMC-Li has been generally prepared by CMC acid form (CMC-H) as an intermediate product treated with a strong acid, which considerably causes a polymer degradation. Here, we report a synthesis method of CMC-Li through the use of a weak acid (acetic acid) and its application in a high energy-density graphite anode. CMC-Li synthesized by acetic acid (CMC-Li (A)) exhibits enhanced physicochemical properties including an appropriate viscosity of ∼3000 mPa·s at a shear rate of 10 s<SUP>-1</SUP>, good slurry stability, and strong adhesion force of 1.4 gf/mm compared to those of CMC-Li synthesized by hydrochloric acid. The high energy-density graphite anode prepared with CMC-Li (A) shows higher charge/discharge capacities and capacity retentions in various rates of 0.05-2 C than those of the electrode prepared with CMC-Na that might be due to the enhanced Li<SUP>+</SUP> ion flux upon cycling.</P> [FIG OMISSION]</BR>

Lifetime Analysis for Comparing POCl₃ Diffused Emitter Doping Characteristics in p-Type Silicon Solar Cells Using QSSPC

Park, HyunJung,Kim, Soo Min,Jeong, Sujeong,Shin, Seung Hyun,Park, Hyomin,Kang, Yoonmook,Lee, Hae-Seok,Kim, Donghwan American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.7

<P>Analysis of the emitter property of solar cells is important because the emitter doping characteristics can affect the surface recombination velocity, contact resistance, emitter saturation current density, and cell efficiency. To analyze the emitter quality, we used the following methods: the four-point probe method, quasi-steady-state photoconductance (QSSPC), and secondary ion mass spectroscopy (SIMS). The four-point probe method is used to measure the doping dose in the emitter. Using QSSPC, we can characterize the emitter quality, including the lifetime of the emitter, and using SIMS, we can measure the concentration of dopants as a function of depth in the emitter. However, SIMS measurement is destructive and limited to the measurement of planar surface wafers. To solve this problem, we investigated the relationship between the minority carrier lifetime and the emitter doping profile using the QSSPC. The relationship between the lifetime and emitter doping profile showed that the lifetime of the emitter decreases as the emitter doping concentration increases. From this result, we performed a lifetime analysis for differently doped POCl3-diffused emitters. The results obtained using the theoretical model for the lifetime agreed with experimental SIMS measurement results, indicating that the model can be used as a quantitative model for comparing emitter doping characteristics.</P>