Efficient and Stable Polymeric Hole Transporting Material in Perovskite Solar Cells

Gyeongho Kang,Guan-Woo Kim,Taiho Park 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

공공예술을 활용한 도시재생지역의 지속가능한 발전 방안 - 부산 감천동 문화마을의 도시재생 사례 분석을 중심으로 -

( Huimin Wang ),( Taiho Kang ) 한국전통조경학회(구 한국정원학회) 2016 Journal of Korean Institute of Traditional Landsca Vol.14 No.-

이 연구는 공공 예술을 활용하여 도심에 위치한 도시재생마을의 지속가능한 발전과 개선방안을 제시하기 위해 수행하였다. 연구를 위해 환경미학의 이론을 근거로 하여 도시공간 환경미술인 벽화의 평가 기준을 델파이 기법을 이용하여 선정하였고 AHP 기법을 이용하여 분석하였다. 부산 감천동 문화마을을 사례 대상으로 지속가능 발전 방안을 모색하기 위해 관광객 및 거주민들에게 설문조사를 실시하여 개선방안을 수립하였다. 연구 결과 감천동 문화마을의 개선방안으로 첫째, 조각 및 벽화 예술작품의 보완이 필요하며 둘째, 예술 작품 제작에 수준 높은 예술가들의 참여를 통해 질적 향상을 도모하여야 한다. 셋째, 마을 내 경관 개선을 위해 식재 수종의 다양성 및 양적 증가가 필요하며 넷째, 마을의 위생 청결 및 주차시설 확보 등 공공 편의시설이 개선되어야 된다. This study is an improvement plan for sustainable Development of that regeneration village in the center of city revitalize regional through the public art. This study uses the theory of environmental aesthetics and got evaluation result by Dephil expert investigation method and the analytic hierarchy process. And exploration through the case of Gamcheon Cultural Village by the questionnaire survey to tourists and denizens then put forward the improvement program. The results of the improvement plan on Gamcheon Cultural Village as follows. Firs to increase the artistic work of sculptures and the murals. Second, improve the mural art work by the professional artist. Third, change the landscape line of the Cultural Village by ensuring that the plants are plentiful .Fourth, improve the cleanliness of the Cultural Village by implementing vehicle management and as well as improving the environmental facilities.

A Competitive Electron Transport Mechanism in Hierarchical Homogeneous Hybrid Structures Composed of TiO₂ Nanoparticles and Nanotubes

Choi, Jongmin,Kang, Gyeongho,Park, Taiho American Chemical Society 2015 Chemistry of materials Vol.27 No.4

<P>We prepared well-defined hierarchical structures comprising doubly open-ended TiO<SUB>2</SUB> nanotube (NT) arrays covered with various layers of few-nanometer-sized TiO<SUB>2</SUB> nanoparticles (NPs) to investigate the electron collection mechanisms in homogeneous hybrid structures. We found that competitive electron transport pathways (direct transport through the NT and randomized transport through the NPs) are present in the homogeneous hybrid structures. Photoinduced electrons generated at the few-nanometer-sized TiO<SUB>2</SUB> NPs directly connected with TiO<SUB>2</SUB> NTs (e.g., isolated and single-layer NPs on the surface of NTs) dominantly traveled to the NTs. With an increasing number of TiO<SUB>2</SUB> NP layers, photoinduced electrons are randomly transported through the TiO<SUB>2</SUB> NP layers. Enhanced light harvesting and efficient charge collection (∼95%) caused by the increased amounts of dye loading and the direct transport through the NT, respectively, are achieved in a structure with ∼1.4 layers of few-nanometer-sized TiO<SUB>2</SUB> NPs, resulting in a power conversion efficiency of 11.3% with a <I>J</I><SUB>SC</SUB> value (22.9 mA/cm<SUP>2</SUP>) close to the theoretical value (∼26 mA/cm<SUP>2</SUP>) of a N719-based dye-sensitized solar cell.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2015/cmatex.2015.27.issue-4/cm504516n/production/images/medium/cm-2014-04516n_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm504516n'>ACS Electronic Supporting Info</A></P>

당대예술의 개입을 통한 농촌마을의 활성화 - 에치고츠마리 사례를 중심으로 -

Huimin Wang,Taiho Kang 전북대학교 부설 휴양및경관계획연구소 2015 휴양및경관연구 (J East Asian Landscape Studies) Vol.9 No.4

이 연구는 에치고츠마리 마을을 대상으로 농촌마을에 당대예술을 도입함으로서 활성화 되어지는 과정과 그 결과를 다룬 것이다. 대상지의 고찰과 당대예술의 도입 계기, 마을의 경관요소, 예술제의 계획, 자원의 활용, 예술 도입 후 성과에 대한 데이터를 분석하여 예술이 농촌마을의 발전에 미친 영향과 지속적인 발전 가능성을 규명하였다. 연구를 통해 당대예술을 이용한 농촌경관의 변화가 농촌마을 활성화에 도움이 되는 것으로 나타났으며 자연 및 예술의 조화에도 영 향을 주는 것으로 파악되었다. 논문은 연구의 목적과 배경, 연구의 대상과 방법, 일본 마을의 경관요소 및 에치고츠마리의 분석, 예술제의 계획 및 자원 이용의 상황에 대한 고찰 그리고 연구 결과로 구성되었다. 연구결과 당대예술의 도입이 에치고츠마리 마을에 미친 좋은 영향은 첫째, 경제적인 수익을 높였으며 둘째, 인구 구조가 변화되면서 전통적인 단일 농경구조가 바뀌었고 셋째, 농민들의 생활방식이 변화되어 새로운 문화가치를 형성했으며 예술제가 에치고츠마리의 새로운 문화의 상징이 되었다. 넷째, 마을의 거주환경, 교통, 공공시설 등 생활환경 등이 개선되었으며 다섯째, 마을의 경관요소 및 공간속성에 변화를 가져왔다. 또한 예술 도입을 통해 에치고츠마리 마을이 다시 활성화 된 사례는 최근 사회적으로 문제되는 농촌마을의 발전에 도움을 줄 수 있을 것이다. This study investigates how the rural villages of Echigo - Tsumari in Japan were resurrected by the contemporary art intervention. This study analyzes the following: (1) the scope of contemporary art intervention, (2) types of landscape of rural villages, (3) plan of the Echigo - Tsumari Art Triennale, (4) ways to use natural resources in an art festival, and (5) data recording the impact of the contemporary art intervention. This study also reveals the possibility of continuous development of rural villages by analyzing the data. This study suggests how to use contemporary art to change the landscape of rural villages for their resurrection and how to integrate art into the environment. The results of this study were derived from its background, purpose, object, and method, as well as the analysis of the landscape of rural villages in Japan, the art festivals, and the exploitation of natural resources. The contemporary art intervention had a few benefits for the region of Echigo - Tsumari. First, this event improved the economic conditions of the region. Second, it controlled population aging and simultaneously improved the single economic structure of the traditional agriculture. Third, it is introduced the farmers to a new culture and improved their lifestyle; this art festival provided a new identity to the people of Echigo - Tsumari. Fourth, this event improved the residential environment, traffic movement, community facilities, et cetera. Fifth, this event provides insights into the spatial and structural transformation of the landscape. In recent times, the development of rural villages has been challenging and difficult, but the rehabilitation of Echigo - Tsumari provides valuable insights into further research.

A Study on Psychological Carrying Capacity in Daerungwon - From the View of Tourists -

Linsen Cao,Hongxu Peng,Taiho Kang 전북대학교 휴양및경관계획연구소 2016 휴양및경관연구 (J East Asian Landscape Studies) Vol.10 No.4

In recent years, the tourism experience of tourists has been impacted seriously with the increase in the number of tourists. Psychological Carrying Capacity (PCC) as an important part of Tourism Carrying Capacity (TCC), is an important criterion for measuring the quality of tourism experience. It is also an important and necessary means of tourism management. Daerungwon, as a symbol of the Gyeongju city, has not been studied on TCC. In this study, the number and the satisfaction degree of tourists in Daerungwon were investigated hourly. Then the mathematical relationship between the two variables was established with regression analysis method. Based on these, the study researched the change rules of the PCC in Daerungwon. The results showed that: (1) The satisfaction degree curve presented inverted “U” shape rather than monotonically decreasing shape with the increase of the number of tourists in Daerungwon. (2) When the instantaneous number of tourists is 193, the satisfaction degree of tourists is the highest. When the instantaneous number is 382, the descent speed of satisfaction degree is the fastest. The best PCC in Daerungwon is 1,198 persons per day. And when the number of tourists reached 2,372, the satisfaction degree will drop quickly. Finally the study verified the influencing factors of PCC from the view of tourists and put forward suggestions on management based on PCC research results. The achieved results can provide the references to the tourism management of Daerungwon.

Dye-Sensitized Solar Cells Employing Doubly or Singly Open-Ended TiO₂ Nanotube Arrays: Structural Geometry and Charge Transport

Choi, Jongmin,Song, Seulki,Kang, Gyeongho,Park, Taiho American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.17

<P>We systematically investigated the charge transport properties of doubly or singly open-ended TiO<SUB>2</SUB> nanotube arrays (DNT and SNT, respectively) for their utility as electrodes in dye-sensitized solar cells (DSCs). The SNT or DNT arrays were transferred in a bottom-up (B-up) or top-up (T-up) configuration onto a fluorine-doped tin oxide (FTO) substrate onto which had been deposited a 2 μm thick TiO<SUB>2</SUB> nanoparticle (NP) interlayer. This process yielded four types of DSCs prepared with SNTs (B-up or T-up) or DNT (B-up or T-up). The photovoltaic performances of these DSCs were analyzed by measuring the dependence of the charge transport on the DSC geometry. High resolution scanning electron microscopy techniques were used to characterize the electrode cross sections, and electrochemical impedance spectroscopy was used to characterize the electrical connection at the interface between the NT array and the TiO<SUB>2</SUB> NP interlayer. We examined the effects of decorating the DNT or SNT arrays with small NPs (sNP@DNT and sNP@SNT, respectively) in an effort to increase the extent of dye loading. The DNT arrays decorated with small NPs performed better than the decorated SNT arrays, most likely because the Ti(OH)<SUB>4</SUB> precursor solution flowed freely into the array through the open ends of the NTs in the DNT case but not in the SNT case. The sNP@DNT-based DSC exhibited a better PCE (10%) compared to the sNP@SNT-based DSCs (6.8%) because the electrolyte solution flow was not restricted, direct electron transport though the NT arrays was possible, the electrical connection at the interface between the NT array and the TiO<SUB>2</SUB> NP interlayer was good, and the array provided efficient light harvesting.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-17/am503934s/production/images/medium/am-2014-03934s_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am503934s'>ACS Electronic Supporting Info</A></P>

In-depth optical characterization of poly(3-hexylthiophene) after formation of nanosecond laser-induced periodic surface structures

Son, Sung Yun,Kang, Gyeongho,Kim, Minjun,Lee, Junwoo,Kim, Taewan,Park, Taiho,Lim, Jongchul The Royal Society of Chemistry 2019 Nanoscale Vol.11 No.16

<P>Herein, poly(3-hexylthiophene) films with periodic wavy surface structures are generated upon laser irradiation at a wavelength of 530 nm using a pulse duration of 5 ns and a repetition frequency of 10 Hz. The optical properties of the films irradiated with 1200, 3000, and 6000 pulses, respectively, are studied using various techniques.</P>

Solution Processable Inorganic-Organic Double-Layered Hole Transport Layer for Highly Stable Planar Perovskite Solar Cells

Kim, Guan-Woo,Kang, Gyeongho,Choi, Kyoungwon,Choi, Hyuntae,Park, Taiho Wiley (John WileySons) 2018 ADVANCED ENERGY MATERIALS Vol.8 No.26

Dopant-free polymeric hole transport materials for highly efficient and stable perovskite solar cells

Kim, Guan-Woo,Kang, Gyeongho,Kim, Jinseck,Lee, Gang-Young,Kim, Hong Il,Pyeon, Limok,Lee, Jaechol,Park, Taiho The Royal Society of Chemistry 2016 ENERGY AND ENVIRONMENTAL SCIENCE Vol.9 No.7

<P>We report a dopant-free polymeric hole transport material (HTM) that is based on benzo[1,2-b:4,5:b']-dithiophene and 2,1,3-benzothiadiazole, which results in highly efficient and stable perovskite solar cells (similar to 17.3% for over 1400 h at 75% humidity). The HTM comprises a random copolymer (RCP), which is characterized using UV-vis absorption spectroscopy, cyclic voltammetry, space-charge-limited current, and grazing-incidence wide-angle X-ray scattering. The RCP-based perovskite solar cell exhibits the highest efficiency (17.3%) in the absence of dopants [lithium bis (trifluoromethanesulfonyl) imide and tert-butylpyridine]. The observed efficiency is attributed to a deep HOMO energy level and high hole mobility. In addition, the long-term stability of the device is dramatically improved by avoiding deliquescent or hygroscopic dopants and by introducing a hydrophobic polymer layer. RCP devices maintain their initial efficiency for over 1400 h at 75% humidity, whereas devices made of HTMs with additives fail after 900 h.</P>

Gradated Mixed Hole Transport Layer in a Perovskite Solar Cell: Improving Moisture Stability and Efficiency

Kim, Guan-Woo,Kang, Gyeongho,Malekshahi Byranvand, Mahdi,Lee, Gang-Young,Park, Taiho American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.33

<P>We demonstrate a simple and facile way to improve the efficiency and moisture stability of perovskite solar cells using commercially available hole transport materials, 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (spiro-OMeTAD) and poly(3-hexylthiophene) (P3HT). The hole transport layer (HTL) composed of mixed spiro-OMeTAD and P3HT exhibited favorable vertical phase separation. The hydrophobic P3HT was more distributed near the surface (the air atmosphere), whereas the hydrophilic spiro-OMeTAD was more distributed near the perovskite layer. This vertical separation resulted in improved moisture stability by effectively blocking moisture in air. In addition, the optimized composition of spiro-OMeTAD and P3HT improved the efficiency of the solar cells by enabling fast intramolecular charge transport. In addition, a suitable energy level alignment facilitated charge transfer. A device fabricated using the mixed HTL exhibited enhanced performance, demonstrating 18.9% power conversion efficiency and improved moisture stability.</P>