期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
New Opportunities for Lanthanide Luminescence 被引量:32
1
作者 Jean-Claude G. Bünzli Steve Comby Anne-Sophie Chauvin Caroline D. B. Vandevyver 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第3期257-274,共18页
Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has b... Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has been kept alive until today when many high-technology applications of lanthanide-containing materials such as energy-saving lighting devices, displays, optical fibers and amplifiers, lasers, responsive luminescent stains for biomedical analyses and in cellulo sensing and imaging, heavily rely on the brilliant and pure-color emission of lanthanide ions. In this review we first outlined the basics of lanthanide luminescence with emphasis on f-f transitions, the sensitization mechanisms, and the assessment of the luminescence efficiency of lanthanide-containing emissive molecular edifices. Emphasis was then put on two fast developing aspects of lanthanide luminescence: materials for telecommunications and light emitting diodes, and biomedical imaging and sensing. Recent advances in NIR-emitting materials for plastic amplifiers and waveguides were described, together with the main solutions brought by researchers to minimize non-radiative deactivation of excited states. The demonstration in 1999 that erbium tris(8-hydroxyquinolinate) displayed a bright green emission suitable for organic light emitting diodes (OLEDs) was followed by realizing that in OLEDs, 25% of the excitation energy leads to singlet states and 75% to triplet states. Since lanthanide ions are good triplet quenchers, they now also play a key role in the development of these lighting devices. Luminescence analyses of biological molecules are among the most sensitive analytical techniques known. The long lifetime of the lanthanide excited states allows time-resolved spectroscopy to be used, suppressing the sample autofluorescence and reaching very low detection limits. Not only visible lanthanide sensors are now ubiquitously provided in medical diagnosis and in cell imaging, but the feasibility of using NIR emission of ions such as YbⅢ is now being tested because of deeper penetration in biological tissues. 展开更多
关键词 lanthanide luminescence SENSITIZATION near infrared telecommunications organic light emitting diode oled time-resolved luminescence in cellulo sensing cell imaging rare earths
下载PDF
Spatio-temporal Dynamics of Urbanization in China Using DMSP/OLS Nighttime Light Data from 1992–2013 被引量:1
2
作者 XU Pengfei LIN Muying JIN Pingbin 《Chinese Geographical Science》 SCIE CSCD 2021年第1期70-80,共11页
Understanding the dynamics of urbanization is essential to the sustainable development of cities. Meanwhile the analysis of urban development can also provide scientifically and effective information for decision-maki... Understanding the dynamics of urbanization is essential to the sustainable development of cities. Meanwhile the analysis of urban development can also provide scientifically and effective information for decision-making. With the long-term Defense Meteorological Satellite Program’s Operational Linescan System(DMSP/OLS) nighttime light images, a pixel level assessment of urbanization of China from 1992 to 2013 was conducted in this study, and the spatio-temporal dynamics and future trends of urban development were fully detected. The results showed that the urbanization and urban dynamics of China experienced drastic fluctuations from 1992 to 2013, especially for those in the coastal and metropolitan areas. From a regional perspective, it was found that the urban dynamics and increasing trends in North Coast China, East Coast China and South Coast China were much more stable and significant than that in other regions. Moreover, with the sustainability estimating of nighttime light dynamics, the regional agglomeration trends of urban regions were also detected. The light intensity in nearly 50% of lighted pixels may continuously decrease in the future, indicating a severe situation of urbanization within these regions. In this study, The results revealed in this study can provided a new insight in long time urbanization detecting and is thus beneficial to the better understanding of trends and dynamics of urban development. 展开更多
关键词 Defense Meteorological Satellite Program’s Operational Linescan System(DMSP/OLS)nighttime light URBANIZATION pixel level detection spatio-temporal dynamics future trends
下载PDF
Improved device reliability in organic light emitting devices by controlling the etching of indium zinc oxide anode
3
作者 廖英杰 娄艳辉 +1 位作者 王照奎 廖良生 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第11期634-638,共5页
A controllable etching process for indium zinc oxide (IZO) films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electr... A controllable etching process for indium zinc oxide (IZO) films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices (OLEDs), a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide (ITO) anode etched by a conventional strong etchant of aqua regia. 展开更多
关键词 indium zinc oxide (IZO) organic light emitting device oled leak current LIFETIME
下载PDF
Reliable high temperature, high humidity flexible thin film encapsulation using Al2O3/MgO nanolaminates for flexible OLEDs 被引量:5
4
作者 Ki Suk Kang So Yeong Jeong +1 位作者 Eun Gyo Jeong Kyung Cheol Choi 《Nano Research》 SCIE EI CAS CSCD 2020年第10期2716-2725,共10页
Since most organic materials are very sensitive to moisture and oxygen, organic light emitting diodes (OLEDs) require an encapsulation layer to protect the active layer from these gases. Since light, flexible and port... Since most organic materials are very sensitive to moisture and oxygen, organic light emitting diodes (OLEDs) require an encapsulation layer to protect the active layer from these gases. Since light, flexible and portable OLEDs are being employed in more diverse climates and environmental conditions, the OLED encapsulation layer must retain robust mechanical properties and stability in high temperature/high humidity conditions. Al2O3 films have demonstrated excellent barrier performance, but they readily hydrolyze when exposed to prolonged harsh environments. In this study, we fabricated a thin film encapsulation (TFE) film that was resistant to hydrolysis, using Al2O3/MgO (AM) nanolaminates. MgO has superior resistance to harsh environments, and the aluminate phase generated by the chemical reaction of Al2O3 and MgO provided excellent barrier performance, even after storage in harsh conditions. A multi-barrier fabricated using the AM nanolaminate showed excellent barrier performance, close to the level required by OLEDs. It did not significantly deteriorate even after a bending test of 1,000 iterations at 0.63% strain. After 1,000 cycle of bending, the electrical properties of the passivated OLEDs were not significantly degraded at shelf-lifetime test where the fabricated device was stored for 50 days in a harsh environment of 60℃, 90% relative humidity. The multi-barrier shows the best performance compared to previous studies on flexible encapsulation that can be used in harsh environments. 展开更多
关键词 thin film encapsulation nanolaminate structure AL2O3 MGO FLEXIBLE organic light emitting diode(oled)
原文传递
Enhancement of light extraction efficiency in OLED with two-dimensional photonic crystal slabs 被引量:2
5
作者 闫荣金 王庆康 《Chinese Optics Letters》 SCIE EI CAS CSCD 2006年第6期353-356,共4页
Light extraction efficiency of organic light emitting diode (OLED) based on various photonic crystal slab (PCS) structures was studied. By using the finite-difference time-domain (FDTD) method, we investigated t... Light extraction efficiency of organic light emitting diode (OLED) based on various photonic crystal slab (PCS) structures was studied. By using the finite-difference time-domain (FDTD) method, we investigated the effect of several parameters, including filling factor and lattice constant, on the enhancement of light extraction efficiency of three basic PCSs, and got the most effective one. Two novel designs of "interlaced" and "double-interlaced" PCS structures based on the most effective basic PCS structure were introduced, and the "interlaced" one was proved to be even more efficient than its prototype. Large enhancement of light extraction efficiency resulted from the coupling to leaky modes in the expended light cone of a band structure, the diffraction in the space between columns, as well as the strong scattering at indium-tinoxide/glass interfaces. 展开更多
关键词 Enhancement of light extraction efficiency in oled with two-dimensional photonic crystal slabs oled
原文传递
Modeling the spatiotemporal dynamics of electric power consumption in China' Mainland using saturation-corrected DMSP/OLS nighttime stable light data 被引量:7
6
作者 Chunyang He Qun Ma +1 位作者 Zhifeng Liu Qiaofeng Zhang 《International Journal of Digital Earth》 SCIE EI 2014年第12期993-1014,共22页
Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption(EPC)is crucial for the effective utilization of electric power in China.The Defense Meteorological Satellite Program’s O... Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption(EPC)is crucial for the effective utilization of electric power in China.The Defense Meteorological Satellite Program’s Operational Linescan System(DMSP/OLS)nighttime stable light(NSL)data have good potential for estimating EPC effectively at large scales.However,saturated lighted pixels contained within the NSL data limit the accuracy of EPC estimation.We developed a new method to correct the saturated lighted pixels,using the SPOT VEGETATION(SPOT/VGT)10-day synthesis product(S10)normalized differ-ence vegetation index(NDVI)data and then modeled the spatiotemporal dynamics of EPC in China' Mainland from 2000 to 2008.The results demon-strated the reliability of our approach with an average Rvalue of 0.93(P<0.001)and an average relative error of-28.92%.EPC in China' Mainland showed an average annual growth rate of 13.46% during the study period from 1198.23 billion kWh in 2000 to 3290.51 billion kWh in 2008.EPC in China' Mainland also showed clear regional variation.Northern coastal China and eastern coastal China consumed 37.61%of the total EPC in China' Mainland,with only 25.96% of the population and 6.11% of the area. 展开更多
关键词 electric power consumption(EPC) DMSP/OLS nighttime stable light data saturation correction spatiotemporal dynamics China'Mainland
原文传递
Optimization of top polymer gratings to improve GaN LEDs light transmission 被引量:5
7
作者 Xiaomin Jin 章蓓 +5 位作者 代涛 魏伟 康香宁 张国义 Simeon Trieu Fei Wang 《Chinese Optics Letters》 SCIE EI CAS CSCD 2008年第10期788-790,共3页
We present a grating model of two-dimensional (2D) rigorous coupled wave analysis (RCWA) to study top diffraction gratings on light-emitting diodes (LEDs). We compare the integrated-transmission of the non-grati... We present a grating model of two-dimensional (2D) rigorous coupled wave analysis (RCWA) to study top diffraction gratings on light-emitting diodes (LEDs). We compare the integrated-transmission of the non-grating, rectangular-grating, and triangular-grating cases for the same grating period of 6 μm, and show that the triangular grating has the best performance. For the triangular grating with 6-μm period, the LED achieves the highest light transmission at 6-μm grating bottom width and 2.9-μm grating depth. Compared with the non-grating case, the optimized light transmission improvement is about 74.6%. The simulation agrees with the experimental data of the thin polymer grating encapsulated flip-chip (FC) GaN-based LEDs for the light extraction improvement. 展开更多
关键词 ABS resins Gallium alloys Gallium nitride Light emitting diodes Light transmission Optical properties Organic light emitting diodes (oled) Polymers Semiconducting gallium TRANSPARENCY
原文传递
Thin-film encapsulation for top-emitting organic light-emitting diode with inverted structure 被引量:3
8
作者 陈超平 李洪婧 +3 位作者 Yong Zhang Changbum Moon Woo Young Kim Chul Gyu Jhun 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第2期57-59,共3页
We theoretically study the light outcoupling efficiency of top-emitting organic light-emitting diode(OLED) with inverted structure and thin-film encapsulation.Thin-film optics is used to optimize the layer thickness... We theoretically study the light outcoupling efficiency of top-emitting organic light-emitting diode(OLED) with inverted structure and thin-film encapsulation.Thin-film optics is used to optimize the layer thickness to obtain high transmittance.Dipole mode is used to analyze the light outcoupling efficiency of the top-emitting OLED.Through this process,we can optimize the thin-film thickness with high transmittance and optimize the outcoupling efficiency of OLED.Compared with previous research,the current design method is a novel process. 展开更多
关键词 EFFICIENCY Organic light emitting diodes (oled)
原文传递
Position dependence of extraction ef f iciency in organic light-emitting diodes with photonic crystal structure 被引量:2
9
作者 黄赛君 叶志成 +3 位作者 陆建钢 苏翼凯 陈超平 何谷峰 《Chinese Optics Letters》 SCIE EI CAS CSCD 2013年第6期73-76,共4页
We demonstrate by finite-difference time-domain simulations that a one-dimensional (1D) photonic crys- tal (PC) structure between glass substrate and indium tin oxide layer can improve the light extraction efficie... We demonstrate by finite-difference time-domain simulations that a one-dimensional (1D) photonic crys- tal (PC) structure between glass substrate and indium tin oxide layer can improve the light extraction efficiency of organic light-emitting diodes. The extraction efficiency depends on the emitters' positions varying laterally in a unit cell of PC. The highest efficiency is obtained when the emitters are under higher refractive index strips. Efficiency decreases when the emitters shift to lower refractive index strips. Simulations for both transverse magnetic and transverse electric modes indicate that when emitters are close to the middle of the higher refractive index strips, the guided wave transmits with less divergence and inhibited reflection because of the guiding effect of higher refractive index strips. A modified method that considers the position effects is proposed to calculate the extraction efficiency more precisely. 展开更多
关键词 Efficiency Organic light emitting diodes (oled) Photonic crystals Refractive index SUBSTRATES
原文传递
MoO_3 as a cathode buffer layer for enhancing the efficiency in white organic light-emitting diodes 被引量:1
10
作者 张静 张方辉 +2 位作者 丁磊 李艳菲 梁田静 《Optoelectronics Letters》 EI 2012年第4期256-259,共4页
Molybdenum trioxide (MOO3) as a cathode buffer layer is inserted between LiF and A1 to improve the efficiency of white organic light-emitting diodes (OLEDs) in this paper..By changing the MoO3 thickness, a higher ... Molybdenum trioxide (MOO3) as a cathode buffer layer is inserted between LiF and A1 to improve the efficiency of white organic light-emitting diodes (OLEDs) in this paper..By changing the MoO3 thickness, a higher current efficiency of 5.79 cd/A is obtained at a current density of 160 mA/cm2 for the device with a 0.8 nm-thick MoO3 layer as the cathode buffer layer, which is approximately two times greater than that of the device without MoO3. The mechanism for improving the device efficiency is discussed. Moreover, at a voltage of 13 V, the device with a 0.8 nm-thick MoO3 layer achieves a higher luminance of 22370 cd/m2, and the Commission Internationale de I'Eclairage (CIE) color coordinate of the device with 1 nm-thick MoO3 layer is (0.33, 0:34), which shows the best color purity. Simple electron-only devices are tested to confirm the impact of the MoO3 layer on the carrier injection. 展开更多
关键词 Buffer layers Cathodes EFFICIENCY Organic light emitting diodes (oled)
原文传递
Light extraction of GaN LEDs with 2-D photonic crystal structure 被引量:1
11
作者 刘宏伟 阚强 +3 位作者 王春霞 於丰 许兴胜 陈弘达 《Chinese Optics Letters》 SCIE EI CAS CSCD 2009年第10期918-920,共3页
Ultraviolet photo-lithography is employed to introduce two-dimensional (2D) photonic crystal (PC) structure on the top surface of GaN-based light emitting diode (LED). PC patterns are transferred to 460-rimthick... Ultraviolet photo-lithography is employed to introduce two-dimensional (2D) photonic crystal (PC) structure on the top surface of GaN-based light emitting diode (LED). PC patterns are transferred to 460-rimthick transparent indium tin oxide (ITO) electrode by inductively coupled plasma (ICP) etching. Light intensity of PC-LED can be enhanced by 38% comparing with the one without PC structure. Rigorous coupled wave analysis method is performed to calculate the light transmission spectrum of PC slab. Simulation results indicate that total internal reflect angle which modulated by PC structure has been increased by 7°, which means that the light extraction efficiency is enhanced outstandingly. 展开更多
关键词 Extraction Gallium alloys Gallium nitride Inductively coupled plasma Light emitting diodes Light transmission Organic light emitting diodes (oled) Photonic crystals Physical optics Semiconducting gallium Surface structure Tin Two dimensional
原文传递
Blue fluorophores comprised of tetraphenylethene and imidazole: aggregation-induced emission and electroluminescence
12
作者 Jiayun XIANG Han NIE +4 位作者 Yibin JIANG Jian ZHOU Hoi Sing KWOK Zujin ZHAO Ben Zhong TANG 《Frontiers of Optoelectronics》 CSCD 2015年第3期274-281,共8页
By melting tetraphenylethene (TPE) and 1,2,4,5-tetraphenyl-lH-imidazole (TPI) units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- ... By melting tetraphenylethene (TPE) and 1,2,4,5-tetraphenyl-lH-imidazole (TPI) units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- luminescence (EL) properties are fully studied. Owing to the presence of TPE unit(s), these fluorophores are weak emitters in solutions, but are induced to emit strongly in the aggregated state, presenting typical aggregation-induced emission characteristics. The experimental and computational results reveal that different connection patterns between TPE and TPI could impact the molecular conjugation greatly, leading to varied emission wavelength, fluorescence quantum yield and EL performance in organic light emitting diodes (OLEDs). The fluorophore built by attaching TPE unit to the 1-position of imidazole ring shows bluest fluorescence, and its EL device emits at deep blue region (445 nm; CIE= (0.16, 0.15)). And the device based on the fluorophore by linking TPE to the 2- position of imidazole ring shows EL at 467 nm (CIE= (0.17, 0.22)) with good efficiencies of 3.17 cd.A ^-1, and 1.77%. 展开更多
关键词 aggregation-induced emission (AIE) tetraphenylethene (TPE) IMIDAZOLE blue fluorescence organic light emitting diode oled
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部