http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Highly stable QD-LED by organic and inorganic dual-encapsulation
박상율,서영수 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
The unique optical properties of quantum dot (QD) have stimulated active researches for the next generation display and illumination. Especially, it attracts great attention in high definition display because it has narrow emission band and high efficiency for replacing OLED. Even so, it is very hard to apply it for industrial products because the optical properties of QD were degraded by oxygen, heat, and moisture. Moreover, photo-stability should be guaranteed too. To enhance QD stability, previously we developed a polymeric microcapsule. Here we present a novel method for strengthening barrier and thermal properties of the microcapsule using inorganic materials. Morphology was studied by SEM and TEM. Stability of QD was checked by life test of QD-LED in terms of applying voltages.
InP/ZnSe/ZnS 양자점을 이용한 QD-LED의 전기 및 광학적 특성
최재건,문대규,Choi, Jae-Geon,Moon, Dae-Gyu 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.3
We have developed quantum dot light emitting diodes (QD-LEDs) using a InP/ZnSe/ZnS multi-shell QD emission layer. The hybrid structure of organic hole transport layer/QD/organic electron transport layer was used for fabricating QD-LEDs. Poly(4-butylphenyl-diphenyl-amine) (poly-TPD) and tris[2,4,6-trimethyl-3-(pyridin-3-yl)phenyl]borane (3TPYMB) molecules were used as hole-transporting and electron-transporting layers, respectively. The emission, current efficiency, and driving characteristics of QD-LEDs with 50, 65 nm thick 3TPYMB layers were investigated. The QD-LED with a 50 nm thick 3TPYMB layer exhibited a maximum current efficiency of 1.3 cd/A.
정공수송층의 재료에 대한 QD-LEDs의 전기 및 광학적 특성 연구
하미영,김강희,문대규 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1
나노결정 양자점 및 이를 활용한 디스플레이는 높은 발광효율, 우수한 색재현성 및 색순도, 소자의 안정성 및 용액공정에 대한 용이성 등을 강점으로 가진다. 본 연구에서는 이와 같이 우수한 특성의 QD(Quantum-Dot)를 발광층으로 사용하고, 용액공정 및 열증착 공정을 이용하여 하이브리드 형태의 고효율 양자점 발광 소자(QD-LEDs)를 제작하였다. 특히, 최적의 QD-LEDs의 소자 제작을 위하여 정공수송층의 재료로 정공 이동도가 우수하고, 용액 공정 시, 적층에 용이한 재료인 Poly-TPD [Poly(N,N’-bis(4- butylphenyl)-N,N’-bis(phenyl)-benzidine] 및 PVK (Poly(N-vinyl carbazole)를 이용하였으며, 각 재료별 두께의 변화에 따라서 QD-LEDs의 전기적, 광학적 특성을 분석하였다. 우리는 Poly-TPD를 정공수송층으로 활용한 녹색 QD-LEDs에서 두께가 250 nm일 때, 14.8cd/A (@ 0.102 mA/cm<sup>2</sup>)의 최대 전류효율을 얻었다. 또한, PVK의 경우는 두께가 100 nm일 때, 11.8cd/A (@ 0.001 mA/cm<sup>2</sup>)의 전류효율을 가졌다. 이와 같은 결과로 두 재료의 전자 및 정공의 밸런스가 서로 다른 특징을 가지는 것을 알 수 있고, 이것은 두 물질의 정공이동도에 기인한 것으로 사료된다.
Choi Yoon-Jeong,Lee Chil Won,Kim Jang Sub 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.12
This paper report on the significantly improved performance of InP/ZnSeS/ZnS quantum dot (QD) devices with multi-functional ligands. These quantum dots in which the monodentate ligand oleylamine is coordinated to the shell surface are reacted with the delocalized bipyridine bidentate ligand, where some oleylamine is replaced by bipyridine. The coordination of the delocalized bidentate bipyridine ligand results in many electronic property changes in the QD-LED (light emitting diode) device. 1H-NMR (nuclear magnetic resonance) and TGA (thermogravimetric analysis) data indicated that up to 60.6% of the native ligands were partially exchanged with the bipyridine ligands. Photoluminescence (PL) spectra before and after ligand substitution show a bathochromic shift of about 2.6 nm due to the electrical resonant properties of the bipyridine ligands. QD-LED devices were fabricated using QDs with substituted bipyridine ligand, and significant improvements in the device properties were observed. Here, we first report the ligand dependence of the photo- and the electroluminescence of green InP/ZnSeS/ZnS quantum dots in QD-LED devices.
장일완,김지완,박창준,Christian Ippen,Tonino Greco,오민석,이정노,김원근,Armin Wedel,한철종,박성규 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.6
The present work shows the effect of ethanolamine surface treatment on inverted InP quantum dot light-emitting diodes (QD-LEDs) with inorganic metal oxide layers. In the inverted structure of ITO/ZnO/InP QDs/CBP/MoO3/Al, a sol-gel derived ZnO film was used as an electron transport layer (ETL) and MoO3 was used as a hole injection layer (HIL). First, ethanolamine was treated as a surface modifier on top of the ZnO electron transport layer. The optical performance of the QDLED device was improved by the ethanolamine surface treatment. Second, low temperature annealing (<200°C) was performed on the ZnO sol-gel electron transport layer, followed by an investigation of the effect of the ZnO annealing temperature. The efficiency of the inverted QD-LEDs was significantly enhanced (more than 3-fold) by optimization of the ZnO annealing temperature.
Electrical Aging Effect of ZnS based Quantum Dots for White Light-Emitting Diodes
Yohan Kim,Christian Ippen,Tonino Greco,Ilwan Jang,박성규,Min Suk Oh,한철종,이정노,Armin Wedel,김지완 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.2
The present work reports cadmium-free colloidal ZnS:Al quantum dot (QD) based white quantum dot lightemitting diodes (QD-LEDs). The device was fabricated with a structure of ITO/PEDOT:PSS/ PVK/QDs/TPBi/ LiF/Al using synthesized ZnS:Al QDs which has 393 nm of peak wavelength and sub peaks in visible wavelength. White emission with high color rending index (CRI) was achieved by the combination of blue emission from PVK and ZnS:Al QDs, electroplex emission at the interface between PVK and ZnS:Al QDs, and Al traps/ defects emission, which are controlled by electrical aging effect. The characteristic of our device shows the potential for spectrum tunable and Cd-free white QD-LEDs in the near future.
Hong S.C.,Gwak S.T.,Park S.,Lee G.J.,Lee J.-G.,Ko J.-H.,Joe S.Y.,Kim Y.,Park T.,Ko Y.W. 한국물리학회 2021 Current Applied Physics Vol.31 No.-
Red quantum dot (QD) films were applied to a conventional white light-emitting-diodes (LEDs) module consisting of 72 LEDs for improving color-rendering properties. Total three QD films with different QD concentrations, two diffuser plates, and six optical configurations were combined and investigated to find an optimized optical structure. QD films formed a red peak near 630 nm in the spectrum which significantly increased the overall color rendering index (CRI). The lateral optical cavity formed by a vertical QD wall and the vertical cavity formed by the diffuser plate and the reflection film in the lighting module played an important role in the improvement of the color-rendering properties. Especially, the adoption of the lateral optical cavity formed by the QD wall was an effective way to improve both efficiency and color rendering properties of the LED lighting. The present result suggests a new possibility of designing high-CRI LED light sources whose color properties can be tuned easily by simply applying and relocating QD components in conventional LED lightings.