共查询到20条相似文献，搜索用时 15 毫秒
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Danyang Li Junjie Wang Miaozi Li Gancheng Xie Biao Guo Lan Mu Haiyang Li Jian Wang Hin‐Lap Yip Junbiao Peng 《Advanced Materials Technologies》2020,5(6)
Perovskite light emitting devices have been expected to be utilized in the field of displays. In this work, a stable FA0.3Cs0.7PbBr3 perovskite quantum dot ink with optimized octane:dodecane cosolvent is obtained by introducing a trace amount of long‐chain ligand of oleylamine (OAm) during the quantum dot purification process. A green electroluminescent matrix device with 120 pixels per inch (PPI) is realized from the ink by using an inkjet printing technique, exhibiting a luminance of 1233 cd m−2, a peak current efficiency of 10.3 cd A−1, and an external quantum efficiency of 2.8%. The results may suggest a possibility of making perovskite quantum dot displays by using the inkjet printing technique. 相似文献
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Jun Pan Li Na Quan Yongbiao Zhao Wei Peng Banavoth Murali Smritakshi P. Sarmah Mingjian Yuan Lutfan Sinatra Noktan M. Alyami Jiakai Liu Emre Yassitepe Zhenyu Yang Oleksandr Voznyy Riccardo Comin Mohamed N. Hedhili Omar F. Mohammed Zheng Hong Lu Dong Ha Kim Edward H. Sargent Osman M. Bakr 《Advanced materials (Deerfield Beach, Fla.)》2016,28(39):8718-8725
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Light‐Emitting Diodes: Light‐Emitting Diodes with Hierarchical and Multifunctional Surface Structures for High Light Extraction and an Antifouling Effect (Small 2/2016) 
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下载免费PDF全文 Young‐Chul Leem Jung Su Park Joon Heon Kim NoSoung Myoung Sang‐Youp Yim Sehee Jeong Wantae Lim Sung‐Tae Kim Seong‐Ju Park 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(2):138-138
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Degradation in organic light‐emitting diodes (OLEDs) is a complex problem. Depending upon the materials and the device architectures used, the degradation mechanism can be very different. In this Progress Report, using examples in both small molecule and polymer OLEDs, the different degradation mechanisms in two types of devices are examined. Some of the extrinsic and intrinsic degradation mechanisms in OLEDs are reviewed, and recent work on degradation studies of both small‐molecule and polymer OLEDs is presented. For small‐molecule OLEDs, the operational degradation of exemplary fluorescent devices is dominated by chemical transformations in the vicinity of the recombination zone. The accumulation of degradation products results in coupled phenomena of luminance‐efficiency loss and operating‐voltage rise. For polymer OLEDs, it is shown how the charge‐transport and injection properties affect the device lifetime. Further, it is shown how the charge balance is controlled by interlayers at the anode contact, and their effects on the device lifetime are discussed. 相似文献
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Metal‐halide perovskites (MHPs) are well suited to be vivid natural color emitters due to their superior optical and electrical properties, such as narrow emission linewidths, easily and widely tunable emission wavelengths, low material cost, and high charge carrier mobility. Since the first development of MHP light‐emitting diodes (PeLEDs) in 2014, many researchers have tried to understand the properties of MHP emitters and the limitations to luminescence efficiency (LE) of PeLEDs, and have devoted efforts to increase the LE of MHP emitters and PeLEDs. Within three and half years, PeLEDs have shown rapidly increased LE from external quantum efficiency ≈0.1% to ≈14.36%. Herein, the factors that limit the LE of PeLEDs are reviewed; the factors are characterized into the following groups: i) photophysical properties of MHP crystals, ii) morphological factors of MHP layers, and iii) problems caused by device architectures. Then, the strategies to overcome those luminescence‐limiting factors in MHP emitters and PeLEDs are critically evaluated. Finally, research directions to further increase the LE of MHP emitters and the potential of MHPs as a core component in next‐generation displays and solid‐state lightings are suggested. 相似文献
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Degradation in organic light‐emitting diodes (OLEDs) is a complex problem. Depending upon the materials and the device architectures used, the degradation mechanism can be very different. In this Progress Report, using examples in both small molecule and polymer OLEDs, the different degradation mechanisms in two types of devices are examined. Some of the extrinsic and intrinsic degradation mechanisms in OLEDs are reviewed, and recent work on degradation studies of both small‐molecule and polymer OLEDs is presented. For small‐molecule OLEDs, the operational degradation of exemplary fluorescent devices is dominated by chemical transformations in the vicinity of the recombination zone. The accumulation of degradation products results in coupled phenomena of luminance‐efficiency loss and operating‐voltage rise. For polymer OLEDs, it is shown how the charge‐transport and injection properties affect the device lifetime. Further, it is shown how the charge balance is controlled by interlayers at the anode contact, and their effects on the device lifetime are discussed. 相似文献
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Yang Shen Li‐Peng Cheng Yan‐Qing Li Wei Li Jing‐De Chen Shuit‐Tong Lee Jian‐Xin Tang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(24)
Perovskite light‐emitting diodes (PeLEDs) show great application potential in high‐quality flat‐panel displays and solid‐state lighting due to their steadily improved efficiency, tunable colors, narrow emission peak, and easy solution‐processing capability. However, because of high optical confinement and nonradiative charge recombination during electron–photon conversion, the highest reported efficiency of PeLEDs remains far behind that of their conventional counterparts, such as inorganic LEDs, organic LEDs, and quantum‐dot LEDs. Here a facile route is demonstrated by adopting bioinspired moth‐eye nanostructures at the front electrode/perovskite interface to enhance the outcoupling efficiency of waveguided light in PeLEDs. As a result, the maximum external quantum efficiency and current efficiency of the modified cesium lead bromide (CsPbBr3) green‐emitting PeLEDs are improved to 20.3% and 61.9 cd A?1, while retaining spectral and angular independence. Further reducing light loss in the substrate mode using a half‐ball lens, efficiencies of 28.2% and 88.7 cd A?1 are achieved, which represent the highest values reported to date for PeLEDs. These results represent a substantial step toward achieving practical applications of PeLEDs. 相似文献
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Da Bin Kim Seungjin Lee Chung Hyeon Jang Jong Hyun Park Ah‐young Lee Myoung Hoon Song 《Advanced Materials Interfaces》2020,7(8)
Metal halide perovskites have deep valence band maximums (VBMs). For example, the VBM of CsPbBr3 is 5.8–6.3 eV. Conjugated polymers can be a potential candidate for the hole transport layer because of their deep highest occupied molecular orbital levels, but their poor compatibility with a hydrophilic perovskite precursor results in the formation of a noncontinuous perovskite film. In addition, antisolvent dripping methods for fabricating perovskite films cause spatially inhomogeneous nucleation, which is undesirable for large‐scale applications. In this work, efficient and large‐area perovskite light‐emitting diodes (PeLEDs) are developed by introducing a poly(9‐vinylcarbazole) (PVK) interlayer and employing a hot‐casting method (substrate preheating). The PVK interlayer increases the depth of the VBM of NiOx (from 5.1 to 5.5 eV), resulting in efficient hole injection. The thermal energy of the preheated substrate facilitates not only the growth of a continuous and pinhole‐free perovskite film, but also the formation of a highly crystalline and preferentially oriented perovskite structure, resulting in improved luminescence properties. Therefore, PeLEDs fabricated using an optimal preheating temperature show an improved external quantum efficiency (from 3.08% to 8.44%) with spatially uniform electroluminescence. Finally, the development of uniform and large‐area PeLEDs (with an active area of 12.8 cm2) is demonstrated. 相似文献
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Sohee Jeon Lianfeng Zhao Young‐Jin Jung Ji Whan Kim Sei‐Yong Kim Hyeokjung Kang Jun‐Ho Jeong Barry P. Rand Jeong‐Hwan Lee 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(8)
Organic–inorganic hybrid perovskite light‐emitting diodes (PeLEDs) are promising for next‐generation optoelectronic devices due to their potential to achieve high color purity, efficiency, and brightness. Although the external quantum efficiency (EQE) of PeLEDs has recently surpassed 20%, various strategies are being pursued to increase EQE further and reduce the EQE gap compared to other LED technologies. A key point to further boost EQE of PeLEDs is linked to the high refractive index of the perovskite emissive layer, leading to optical losses of more than 70% of emitted photons. Here, it is demonstrated that a randomly distributed nanohole array with high‐index contrast can effectively enhance outcoupling efficiency in PeLEDs. Based on a comprehensive optical analysis on the perovskite thin film and outcoupling structure, it is confirmed that the nanohole array effectively distributes light into the substrate for improved outcoupling, allowing for 1.64 times higher light extraction. As a result, highly efficient red/near‐infrared PeLEDs with a peak EQE of 14.6% are demonstrated. 相似文献
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《Small Methods》2018,2(6)
The recent progress in perovskite nanocrystals, including synthetic methods and their applications beyond solar cells, is discussed. Specifically, different synthetic routes to prepare various perovskite nanocrystals are considered, followed by their applications, including light‐emitting diodes, amplified spontaneous emission and lasing, photodetectors, resistance random access memory devices, and piezoelectric nanogenerators. Finally, an outlook for the future potential applications and possible challenges of perovskite nanocrystals is addressed. 相似文献
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