共查询到20条相似文献,搜索用时 31 毫秒
1.
Solution‐processable thermally activated delayed fluorescence emitters for application in organic light emitting diodes
下载免费PDF全文
![点击此处可从《Journal of the Society for Information Display》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Katsuaki Suzuki Chihaya Adachi Hironori Kaji 《Journal of the Society for Information Display》2017,25(8):480-485
Solution‐processed organic light emitting diodes (OLEDs) have been fabricated using the thermally activated delayed fluorescence (TADF) emitter, DACT‐II, and its soluble derivative, tBu‐DACT‐II, as emitting dopants. DACT‐II reportedly exhibits very high external quantum efficiencies (EQEs) in vacuum‐processed OLEDs. The solution‐processed DACT‐II‐based and tBu‐DACT‐II‐based OLEDs exhibited external quantum efficiency exceeding the theoretical upper limit of classical fluorescent OLEDs. 相似文献
2.
Meng‐Ting Lee Chi‐Hung Liao Chih‐Hung Tsai Chin H. Chen 《Journal of the Society for Information Display》2006,14(1):61-64
Abstract— A highly efficient deep‐blue organic light‐emitting device (OLED) incorporating a novel composite hole‐transport layer (c‐HTL) and an emitter based on the new non‐symmetrical mono(styryl)amine fluorescent dopant in the stable host MADN, which achieved a luminance efficiency of 5.4 cd/A with a Commission Internationale d'Eclairage (CIEx,y) of (0.14, 0.13) and an external quantum efficiency of 5.1% at 20 mA/cm2 and 6.8 V, is reported. The increased device efficiency is attributed to an improved balance between hole and electron currents in the recombination zone. 相似文献
3.
Tatsuya Ryowa Takeshi Ishida Yusuke Sakakibara Keisuke Kitano Masaya Ueda Makoto Izumi Yuko Ogura Masanori Tanaka Soichiro Nikata Mayuko Watanabe Mikihiro Takasaki Tetsuji Itoh Akiharu Miyanaga 《Journal of the Society for Information Display》2020,28(5):401-409
We report outstanding electroluminescence properties of high‐efficiency blue cadmium‐free quantum dot light‐emitting diodes (QD‐LED). External quantum efficiency (EQE) of 14.7% was achieved for QD‐LED emitting at 428 nm. Furthermore, we developed high‐efficiency and narrow wavelength emission zinc selenide (ZnSe) nanocrystals emitting at 445 nm and achieved QD‐LED with an EQE of 10.7%. These new QDs have great potential to be used in next‐generation QD‐LED display with wide color gamut. 相似文献
4.
Wei‐En Hsu Chao‐Te Lee Hoang Yan Lin 《Journal of the Society for Information Display》2011,19(11):847-853
Abstract— Solar‐cell‐integrated organic light‐emitting diodes (OLEDs) were fabricated with both high contrast ratio and energy‐recycling ability. However, the luminous efficiency of the integrated devices is reduced to 50% of that of conventional top‐emitting OLEDs. A novel structure to recover the luminous efficiency from 50% to near 85% by applying a distributed Bragg reflector (DBR) made of 20 layers of GaN/AlN was demonstrated. It saves about 40% of the electric power than that of a device without a DBR. The contrast ratio remains high compared to that of conventional OLEDs. In this paper, simulations were conducted first to prove our models and assumptions. Then, two types of thin‐film solar cells — CdTe and CIGS solar cells — were used. They had different contrast ratios as well as viewing‐angle properties. Finally, the emission spectrum was calculated to be 11 nm FWHM, which is narrower than that for the emission spectrum of a typical microcavity OLED and has the advantage of having saturated colors. 相似文献
5.
Tetsuya Masuda Yuki Nakano Yoshiaki Takahashi Hirokatsu Ito Keiji Okinaka Emiko Kambe Yuichiro Kawamura Hitoshi Kuma 《Journal of the Society for Information Display》2018,26(3):146-152
We developed new fluorescent blue dopants (BDs) for achieving high‐efficient blue organic light‐emitting diode. A new BD showed both high photoluminescent quantum yield >0.9 and highly horizontal orientation (S′ > 0.9) in doped film with keeping a chemical stability by introducing suitable substituents. We developed hole transporting materials and optimized the combination of hole transporting layers to decrease a carrier accumulation at the interface between electron blocking layer and emission layer. We found that the external quantum efficiency dependency from low to high current density was turned flat by promoting hole injection into emission layer. The top‐emission organic light‐emitting diode using the new BD and the optimized device architecture exhibited high efficiency of L/J/CIEy around 200 at CIEy = 0.043. 相似文献
6.
Gerard Cummins Ian Underwood Anthony Walton 《Journal of the Society for Information Display》2011,19(4):360-367
Abstract— Positively doped, intrinsic, negatively doped organic light‐emitting diodes (PIN‐OLEDs) have been shown to exhibit high efficiency and a long lifetime compared to conventional small‐molecule OLEDs (SM‐OLEDs). The improved performance of PIN‐OLEDs makes them attractive for use in display applications. Knowledge of the electrical load exhibited by these devices is used to develop an equivalent electrical‐circuit model. Such models are used by circuit designers to assist with the precise design of active‐matrix‐display driver circuits used in such applications. In this paper, the development of a SPICE model for a top‐emitting PIN‐OLED stack is reported. 相似文献
7.
Shun‐Wei Liu Chih‐Hsien Yuan Shi‐Jay Yeh Min‐Fei Wu Chin‐Ti Chen Chih‐Chien Lee 《Journal of the Society for Information Display》2011,19(4):346-352
Abstract— A new type of single‐layer blue‐phosphorescence organic light‐emitting devices (OLEDs) containing poly(9‐vinylcarbazole) (PVK) and small‐molecule‐based amorphous ambipolar bis(3,5‐di(9H‐carbazol‐9‐yl)phenyl) diphenylsilane (SimCP2) as the co‐host material have been demonstrated. All active materials [PVK, SimCP2, Flrpic (blue‐phosphorescence dopant), and OXD‐7 (electron transport)] were mixed in a single layer for solution processing in the fabrication of OLEDs. The SimCP2 small‐molecule host has adequate high electron and hole‐carrier mobiltieis of ~10?4 cm2/V‐sec and a sufficiently large triplet state energy of ~2.70 eV in confining emission energy on FIrpic. Based on such an architecture for single‐layer devices, a maximum external quantum efficiency of 6.2%, luminous efficiency of 15.8 cd/A, luminous power efficiency of 11 lm/W, and Commision Internale de l'Eclairage (CIEx,y) coordinates of (0.14,0.32) were achieved. Compared with those having PVK as the single‐host material, the improvement in the device performance is attributed to the balance of hole and electron mobilities of the co‐host material, efficient triplet‐state energy confinement on FIrpic, and the high homogeneity of the thin‐film active layer. Flexible blue‐phosphorescence OLEDs based on solution‐processed SimCP2 host material (withou PVK) have been demonstrated as well. 相似文献
8.
Masaya Adachi Sukekazu Aratani Kaoru Yanagawa 《Journal of the Society for Information Display》2008,16(8):875-881
Abstract— The blue‐light‐emission properties of organic light‐emitting‐diode (OLED) displays must be enhanced to meet the requirements for color purity and luminous efficiency because few blue‐light‐emitting materials meet these requirements. This is particularly true for polymeric and phosphorescent light‐emitting materials. To attain the required purity and efficiency, a polarized‐light‐recycling structure for blue light that is called a blue enhanced circular polarizer (BECP) has been developed. The principle of the structure and the fabricated prototype device is described and it is shown that the structure increases blue‐light intensity and color purity, improves efficiency, provides a wide color gamut, and limits ambient‐light reflection. 相似文献
9.
Baek‐woon Lee Young‐gu Ju Young In Hwang Hae‐yeon Lee Chi Woo Kim Jin Seok Lee Jun Hyung Souk 《Journal of the Society for Information Display》2009,17(2):151-157
Abstract— Two optical structures used for a bottom‐emitting white organic light‐emitting diode (OLED) is reported. An RGBW color system was employed because of its high efficiency. For red, green, and blue (RGB) subpixels, the cavity resonance was enhanced by the use of a dielectric mirror, and for the white (W) subpixel, the mirror was removed. The optical length of the cavities was controlled by two different ways: by the thickness of the dielectric filter on top of the mirror or by the angle of oblique emission. With both methods, active‐matrix OLEDs (AMOLEDs) that reproduced a color gamut exceeding 100% of the NTSC (National Television System Committee) standard were fabricated. More importantly, the transmission of a white OLED through R/G/B color filters was significantly higher (up to 50%) than that of a conventional structure not employing a mirror, while at the same time as the color gamut increased from ~75 to ~100% NTSC. 相似文献
10.
Akihiro Chida Tomoya Aoyama Shingo Eguchi Tatsunori Inoue Naoyuki Senda Tatsuya Sakuishi Hisao Ikeda Satoko Shitagaki Nobuharu Ohsawa Hideko Inoue Kunihiko Suzuki Hiromi Seo Toshiki Sasaki Yusuke Nonaka Harue Nakashima Tsunenori Suzuki Takeyoshi Watabe Satoshi Seo Yoshiharu Hirakata Shunpei Yamazaki Seiji Yasumoto Masataka Sato Yuki Yasuda Shoji Okazaki Wataru Nakamura Seiichi Mitsui 《Journal of the Society for Information Display》2013,21(10):422-432
We developed a high‐performance 3.4‐in. flexible active‐matrix organic light‐emitting diode (AMOLED) display with remarkably high resolution using an oxide semiconductor in a backplane, by applying our transfer technology that utilizes metal separation layers. Using this panel, we also fabricated a prototype of a side‐roll display for mobile uses. In these AMOLED displays, a white OLED combined with a color filter was used in order to achieve remarkably high resolution. For the white OLED, a tandem structure in which a phosphorescent emission unit and a fluorescent emission unit are serially connected with an intermediate layer sandwiched between the emission units was employed. Furthermore, revolutionary technologies that enable a reduction in power consumption in both the phosphorescent and fluorescent emission units were introduced to the white tandem OLED. 相似文献
11.
Takuya Komoda Nobuhiro Ide Kittichungchit Varutt Kazuyuki Yamae Hiroya Tsuji Yuko Matsuhisa 《Journal of the Society for Information Display》2011,19(11):838-846
Abstract— Several white‐OLED structures with a high color‐rendering index (CRI) were investigated for lighting applications. A two‐unit fluorescent/phosphorescent hybrid white OLED achieved an excellent CRI of 95, high luminous efficacy of 37 lm/W, and long lifetime of over 40,000 hours at 1000 cd/m2. White‐OLED lighting panels of 8 × 8 cm for high‐luminance operation were fabricated, and a stable emission at 3000 cd/m2 was confirmed. Quite a small variation in chromaticity in a different directions was achieved by using an optimized optical device structure. With a light‐outcoupling substrate, a higher efficacy of 56 lm/W, high CRI of 91, and longer half‐decay lifetime of over 150,000 hours at 1000 cd/m2 was achieved. All‐phosphorescent white OLEDs placed on the light‐outcoupling substrate show a high CRI of 85 and higher efficacy of 65 lm/W with a fairly good half‐decay lifetime of over 30,000 hours. With a further voltage reduction and a high‐index spherical extractor, 128 lm/W at 1000 cd/m2 has been achieved. 相似文献
12.
Sean Xia Kwang‐Ohk Cheon Jason J. Brooks Mark Rothman Tan Ngo Patrick Hett Raymond C. Kwong Mike Inbasekaran Julie J. Brown Takuya Sonoyama Masaki Ito Shunichi Seki Satoru Miyashita 《Journal of the Society for Information Display》2009,17(2):167-172
Abstract— A new approach to full‐color printable phosphorescent organic light‐emitting devices (P2OLEDs) is reported. Unlike conventional solution‐processed OLEDs that contain conjugated polymers in the emissive layer, the P2OLED's emissive layer consists of small‐molecule materials. A red P2OLED that exhibits a luminous efficiency of 11.6 cd/A and a projected lifetime of 100,000 hours from an initial luminance of 500 cd/m2, a green P2OLED with a luminous efficiency of 34 cd/A and a projected lifetime of 63,000 hours from an initial luminance of 1000 cd/m2, a light‐blue P2OLED with a luminous efficiency of 19 cd/A and a projected lifetime 6000 hours from an initial luminance of 500 cd/m2, and a blue P2OLED with a luminous efficiency of 6.2 cd/A and a projected lifetime of 1000 hours from an initial luminance of 500 cd/m2 is presented. 相似文献
13.
Philipp Wellmann Michael Hofmann Olaf Zeika Ansgar Werner Jan Birnstock Rico Meerheim Gufeng He Karsten Walzer Martin Pfeiffer Karl Leo 《Journal of the Society for Information Display》2005,13(5):393-397
Abstract— High‐performance organic light‐emitting diodes (OLEDs) are promoting future applications of solid‐state lighting and flat‐panel displays. We demonstrate here that the performance demands for OLEDs are met by the PIN (p‐doped hole‐transport layer/intrinsically conductive emission layer/n‐doped electron‐transport layer) approach. This approach enables high current efficiency, low driving voltage, as well as long OLED lifetimes. Data on very‐high‐efficiency diodes (power efficiencies exceeding 70 lm/W) incorporating a double‐emission layer, comprised of two bipolar layers doped with tris(phenylpyridine)iridium [Ir(ppy)3], into the PIN architecture are shown. Lifetimes of more than 220,000 hours at a brightness of 150 cd/m2 are reported for a red PIN diode. The PIN approach further allows the integration of highly efficient top‐emitting diodes on a wide range of substrates. This is an important factor, especially for display applications where the compatibility of PIN OLEDs with various kinds of substrates is a key advantage. The PIN concept is very compatible with different backplanes, including passive‐matrix substrates as well as active‐matrix substrates on low‐temperature polysilicon (LTPS) or, in particular, amorphous silicon (a‐Si). 相似文献
14.
Takahiro Ishisone Satoshi Seo Yusuke Nonaka Takuya Kawata Nobuharu Ohsawa 《Journal of the Society for Information Display》2014,22(8):404-411
We succeeded in developing a single‐unit hybrid organic light‐emitting diode (OLED) device with efficient light emission from both a phosphorescent layer and a fluorescent layer. The single‐unit hybrid OLED achieved a power efficiency higher than that of a two‐unit hybrid tandem OLED with phosphorescent and fluorescent layers. 相似文献
15.
Shinji Takasugi Hong‐Jae Shin Min‐Kyu Chang Sam‐Min Ko Hyo‐Jin Park Jeong‐Pyo Lee Han‐Seop Kim Chang‐Ho Oh 《Journal of the Society for Information Display》2016,24(7):410-418
In this paper, we present novel organic light‐emitting diode (OLED) display panel compensation technologies for large‐sized ultra‐high‐definition OLED TVs considering variations of threshold voltage, mobility, channel size, OLED efficiency, and OLED uniformity. Using these technologies, we have successfully launched 55‐, 65‐ and 77‐in. ultra‐high‐definition OLED TVs. 相似文献
16.
Shi‐Jay Yeh Chin‐Ti Chen Yi‐Hwa Song Yun Chi Meng‐Huan Ho 《Journal of the Society for Information Display》2005,13(10):857-862
Abstract— A new type of ancillary ligand for blue‐emitting heteroleptic iridium complexes has been successfully developed. New ligands, 3‐(trifluoromethyl)‐5‐(pyridin‐2‐yl)‐1,2,4‐triazolate and 5‐(pyridin‐2‐yl)‐tetrazolate, show stronger blue‐shifting power than that of the picolate of FIrpic [iridium (III) bis(4,6‐difluorophenylpyridinato)picolate]. Organic light‐emitting diodes (OLEDs) fabricated with a new complex, FIrtaz [iridium (III) bis(4,6‐difluorophenylpyridinato)(5‐(pyridine‐2‐yl)‐1,2,4‐triazolate) or FIrN4 [(iridium (III) bis(4,6‐difluorophenylpyridinato)(5‐(pyridin‐2‐yl)‐tetrazolate], as the blue dopant in the host of mCP [1,3‐ bis(9‐carbazolyl)benzene], exhibit near‐saturated blue electrophosphorescence with Commision Internale de l'Eclairage (CIEx,y) coordinates of (0.14, 0.18) and (0.15, 0.24), respectively. 相似文献
17.
Gufeng He Carsten Rothe Sven Murano Ansgar Werner Olaf Zeika Jan Birnstock 《Journal of the Society for Information Display》2009,17(2):159-165
Abstract— The three critical parameters in determining the commercial success of organic light‐emitting diodes (OLEDs), both in display and lighting applications, are power efficiency, lifetime, and price competitiveness. PIN technology is widely considered as the preferred way to maximize power efficiency and lifetime. Here, a high‐efficiency and long‐lifetime white‐light‐emitting diode, which has been realized by stacking a blue‐fluorescent emission unit together with green‐ and red‐phosphorescent emission units, is reported. Proprietary materials have been used in transport layers of each emission unit, which significantly improves the power efficiency and stability. The power efficiency at 1000 cd/m2 is 38 lm/W with CIE color coordinates of (0.43, 0.44) and a color‐rendering index (CRI) of 90. An extrapolated lifetime at an initial luminance of 1000 cd/m2 is above 100,000 hours, which fulfils the specifications for most applications. The emission color can also be easily tuned towards the equal‐energy white for display applications by selecting emitting materials and varying the transport‐layer cavities. 相似文献
18.
Jeffrey P. Spindler Tukaram K. Hatwar 《Journal of the Society for Information Display》2009,17(10):861-868
Abstract— Highly efficient tandem white OLEDs based on fluorescent materials were developed for display and solid‐state‐lighting (SSL) applications. In both cases, the white OLED must have high power efficiency and long lifetime, but there are a number of attributes unique to each application that also must be considered. Tandem OLED technology has been demonstrated as an effective approach to increase luminance, extend OLED lifetime, and allow for use of different emitters in the individual stacks for tuning the emission spectrum to achieve desired performance. Here, examples of bottom‐emission tandem white OLEDs based on small‐molecule fluorescent emitters designed for displays and for SSL applications are reported. A two‐stack tandem white OLED designed for display applications achieved 36.5‐cd/A luminance efficiency, 8500K color temperature, and lifetime estimated to exceed 50,000 hours at 1000 cd/m2. This performance is expected to meet the specifications for large AMOLED displays. A two‐stack tandem white OLED designed for SSL applications achieved 20‐lm/W power efficiency, 38‐cd/A luminance efficiency, 3500K color temperature, and lifetime estimated to exceed 140,000 hours at 1000 cd/m2. With the use of proven light‐extraction techniques, it is estimated that this tandem device will exceed 40 lm/W with more than 500,000‐hour lifetime, performance that should be sufficient for first‐generation lighting products. 相似文献
19.
Jan Birnstock Tobias Canzler Michael Hofmann Andrea Lux Sven Murano Philipp Wellmann Ansgar Werner 《Journal of the Society for Information Display》2008,16(2):221-229
Abstract— Currently, three issues are identified that decide upon the commercial success of organic light‐emitting diodes (OLEDs), both in display and lighting applications: power efficiency, lifetime, and price competitiveness. PIN OLEDs are widely seen as the preferred way to maximize power efficiency. Here, it is reported that this concept also delivers the world longest lifetimes. For a highly efficient deep‐red PIN OLED, a half‐lifetime of 25,000 hours for a starting brightness of 10,000 cd/m2 and a minimal voltage increase over lifetime is reported. This value corresponds to more than 1 × 106 hours at 1000 cd/m2 using an exponent of n = 1.7, which was measured by driving the OLEDs at different starting luminances. Because there is no initial luminance drop, these PIN OLEDs also exhibit a very high 80% lifetime (>300,000 hours at 1000 cd/m2). New record lifetime values for blue and green will be reported as well. Additionally, further topics that have impact on the production yield and cost such as the newly developed air‐stable organic n‐doping material NDN‐26 and top‐emitting structures will be discussed. 相似文献
20.
Chun‐Liang Lin Ping‐Yuan Hsieh Huo‐Hsien Chiang Chung‐Chih Wu 《Journal of the Society for Information Display》2005,13(3):253-259
Abstract— Top‐emitting organic light‐emitting devices (OLEDs) have several technical merits for application in active‐matrix OLED displays. Generally, stronger microcavity effects inherent with top‐emitting OLEDs, however, complicate the optimization of device efficiency and other viewing characteristics, such as color and viewing‐angle characteristics. In this paper, using the rigorous classical electromagnetic model based on oscillating electric dipoles embedded in layered structures, the emission characteristics of top‐emitting OLEDs as a function of device structures will be analyzed. From comprehensive analysis, trends in the dependence of ewmission characteristics on device structures were extracted, and, accordingly, a general methodology for optimizing viewing characteristics of top‐emitting OLEDs for display applications will be suggested. The effectiveness of the analysis and the methodology was confirmed by experimental results. 相似文献