• Title/Summary/Keyword: semiconductors

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NiOx-based hole injection layer for organic light-emitting diodes (유기발광소자에 적용 가능한 NiOx 기반의 정공주입층 연구)

  • Kim, Junmo;Gim, Yejin;Lee, Wonho;Lee, Donggu
    • Journal of Sensor Science and Technology
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    • v.30 no.5
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    • pp.309-313
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    • 2021

  • Organic semiconductors have received tremendous attention for their research because of their tunable electrical and optical properties that can be achieved by changing their molecular structure. However, organic materials are inherently unstable in the presence of oxygen and moisture. Therefore, it is necessary to develop moisture and air stable semiconducting materials that can replace conventional organic semiconductors. In this study, we developed a NiOx thin film through a solution process. The electrical characteristics of the NiOx thin film, depending on the thermal annealing temperature and UV-ozone treatment, were determined by applying them to the hole injection layer of an organic light-emitting diode. A high annealing temperature of 500 ℃ and UV-ozone treatment enhanced the conductivity of the NiOx thin films. The optimized NiOx exhibited beneficial hole injection properties comparable those of 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN), a conventional organic hole injection layer. As a result, both devices exhibited similar power efficiencies and the comparable electroluminescent spectra. We believe that NiOx could be a potential solution which can provide robustness to conventional organic semiconductors.

  • https://doi.org/10.46670/JSST.2021.30.5.309 인용 PDF KSCI

Effects of strain on the optical and magnetic properties of Ce-doped ZnO

  • Xu, Zhenchao;Hou, Qingyu;Guo, Feng;Jia, Xiaofang;Li, Cong;Li, Wenling
    • Current Applied Physics
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    • v.18 no.12
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    • pp.1465-1472
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    • 2018

  • The magnetic and optical properties of Ce-doped ZnO systems have been widely demonstrated, but the effects of different strains of Ce-doped ZnO systems remain unclear. To solve these problems, this study identified the effects of biaxial strain on the electronic structure, absorption spectrum, and magnetic properties of Ce-doped ZnO systems by using a generalized gradient approximation + U (GGA + U) method with plane wave pseudopotential. Under unstrained conditions, the formation energy decreased, the system became stable, and the doping process became easy with the increase in the distances between two Ce atoms. The band gap of the systems with different strains became narrower than that of undoped ZnO without strain, and the absorption spectra showed a red shift. The band gap narrowed, and the red shift became weak with the increase of compressive strain. By contrast, the band gap widened, and the red shift became significant with the increase of tensile strain. The red shift was significant when the tensile strain was 3%. The systems with -1%, 0%, and 1% strains were ferromagnetic. For the first time, the magnetic moment of the system with -1% strain was found to be the largest, and the system showed the greatest beneficial value for diluted magnetic semiconductors. The systems with -3%, -2%, 2%, and 3% strains were non-magnetic, and they had no value for diluted magnetic semiconductors. The ferromagnetism of the system with -1% strain was mainly caused by the hybrid coupling of Ce-4f, Ce-5d, and O-2p orbits. This finding was consistent with Zener's Ruderman-Kittel-Kasuya-Yosida theory. The results can serve as a reference for the design and preparation of new diluted magnetic semiconductors and optical functional materials.

  • https://doi.org/10.1016/j.cap.2018.08.014 인용 KSCI

Ternary Blend Organic Solar Cells Trends based on PM6:Y6 (PM6:Y6를 기반으로 한 삼중 혼합 유기 태양전지 동향)

  • Dong Hwan Yun;Gwang Yong Shin;Yun Hye Jung;YeongWoo Ha;Gi-Hwan Kim
    • Current Photovoltaic Research
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    • v.11 no.3
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    • pp.79-86
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    • 2023

  • As we strive to mitigate the environmental impact caused by the use of fossil fuels, the exploration of alternative energy sources has gained significant attention. Solar energy, in particular, has emerged as a promising solution due to its eco-friendly nature and virtually limitless availability. Among the various types of solar cells that harness this abundant energy source, organic solar cells have garnered considerable interest. Organic solar cells feature a photo-active layer composed of organic semiconductors, offering a range of appealing advantages such as cost-effectiveness, flexibility, translucency, and the ability to produce customizable colors. However, the commercialization of organic solar cells has been impeded by certain challenges, notably their relatively low efficiency and stability. To overcome these obstacles and pave the way for wider adoption, researchers have been exploring innovative approaches, including the implementation of ternary blend organic solar cells. This strategy involves introducing a third component into the photo-active layer alongside the organic semiconductors, with the aim of enhancing the overall performance of the solar cell. In this paper, we delve into the issues associated with organic solar cells and focus on one potential solution: ternary blend organic solar cells. Specifically, we examine the application of this approach to PM6:Y6, which stands as one of the most popular combinations of organic semiconductors. By investigating the potential of ternary blends, particularly utilizing PM6:Y6, we aim to accelerate the commercialization of organic solar cells.

  • https://doi.org/10.21218/CPR.2023.11.3.079 인용 PDF