Pub Date : 2022-07-18DOI: 10.1080/15980316.2022.2097484
Yeong Heon Jeong, C. Joo, Hyein Jeong, Jonghee Lee, Yun-hi Kim
ABSTRACT A new 2-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene-8-yl)-4-(trimethylsilyl)pyridine-based iridium complex was synthesized for efficient solution-processed sky-blue phosphorescent organic light-emitting diodes (PhOLEDs). The effect of dioxaboranaphthoanthracene instead of phenyl with the electron-accepting group, as well as the bulky pyridine with the trimethylsilyl group, on the ligand was investigated. The new dopant was found to have an extremely high photoluminescence quantum yield of 94% when doped in an emissive layer. As a result, the solution-processed blue PhOLED consisting of a simple structure without any interlayer exhibited remarkable light-emitting performance with an external quantum efficiency of 8.93% and a current efficiency of 23.56 cd/A.
{"title":"Solution-processed sky-blue phosphorescent organic light-emitting diodes based on 2-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene-8-yl)-4-(trimethylsilyl)pyridine chelated iridium complex","authors":"Yeong Heon Jeong, C. Joo, Hyein Jeong, Jonghee Lee, Yun-hi Kim","doi":"10.1080/15980316.2022.2097484","DOIUrl":"https://doi.org/10.1080/15980316.2022.2097484","url":null,"abstract":"ABSTRACT A new 2-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene-8-yl)-4-(trimethylsilyl)pyridine-based iridium complex was synthesized for efficient solution-processed sky-blue phosphorescent organic light-emitting diodes (PhOLEDs). The effect of dioxaboranaphthoanthracene instead of phenyl with the electron-accepting group, as well as the bulky pyridine with the trimethylsilyl group, on the ligand was investigated. The new dopant was found to have an extremely high photoluminescence quantum yield of 94% when doped in an emissive layer. As a result, the solution-processed blue PhOLED consisting of a simple structure without any interlayer exhibited remarkable light-emitting performance with an external quantum efficiency of 8.93% and a current efficiency of 23.56 cd/A.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43902151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.1080/15980316.2022.2039789
Woongseob Han, Jae-Min Jeon, myeong-ho Choi, Jae-Hyeung Park
We present a novel design of the lightguide type optical see-through Maxwellian near-eye display. The proposed display reconfigures vertically long input images to horizontally long output images for wide horizontal viewing-angle. The reconfiguration of the input images is optically performed by using folding holographic optical elements and different numbers of total internal reflections within the lightguide. The upper and lower parts of the in-coupled image undergo different numbers of total internal reflections, being separated into two images. After the separation, the upper part is additionally diffracted by the folding holographic optical element to the side of the lower part. Finally, the horizontally tiled upper and lower parts are out-coupled towards the eye by corresponding holographic optical elements. The optical power of the output couplers converges the output image to a focal spot on the eye pupil so that users experience all-in-focus images. In the optical experiment, the wavelength difference between the display and the holographic optical element recording system was pre-compensated by adjusting the recording angle. Our prototype successfully demonstrates horizontal tiling of the upper and lower parts of the input images, showing a two-times larger output horizontal field of view than the input.
{"title":"Lightguide type Maxwellian near-eye display with enlarged horizontal field of view by optical reconfiguration of input image","authors":"Woongseob Han, Jae-Min Jeon, myeong-ho Choi, Jae-Hyeung Park","doi":"10.1080/15980316.2022.2039789","DOIUrl":"https://doi.org/10.1080/15980316.2022.2039789","url":null,"abstract":"We present a novel design of the lightguide type optical see-through Maxwellian near-eye display. The proposed display reconfigures vertically long input images to horizontally long output images for wide horizontal viewing-angle. The reconfiguration of the input images is optically performed by using folding holographic optical elements and different numbers of total internal reflections within the lightguide. The upper and lower parts of the in-coupled image undergo different numbers of total internal reflections, being separated into two images. After the separation, the upper part is additionally diffracted by the folding holographic optical element to the side of the lower part. Finally, the horizontally tiled upper and lower parts are out-coupled towards the eye by corresponding holographic optical elements. The optical power of the output couplers converges the output image to a focal spot on the eye pupil so that users experience all-in-focus images. In the optical experiment, the wavelength difference between the display and the holographic optical element recording system was pre-compensated by adjusting the recording angle. Our prototype successfully demonstrates horizontal tiling of the upper and lower parts of the input images, showing a two-times larger output horizontal field of view than the input.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47707809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-24DOI: 10.1080/15980316.2022.2089750
Kyung Hyung Lee, Jae Min Kim, S. Jeong, Ji‐Ho Baek, Jeongdae Seo, I. Song, Sang Beom Kim, H. Choi, Jun Yeob Lee
Triplet–triplet fusion (TTF) has been an efficiency-enhancing mechanism in fluorescent organic light-emitting diodes (OLEDs) caused by the collision of two triplet excitons. However, achieving a high TTF ratio in fluorescent OLEDs has been difficult despite device strategies to maximize the triplet exciton density within a narrow recombination zone near the electron blocking layer (EBL) due to charge imbalance and hole accumulation between the TTF type emitter and EBL. Based on a trap-detrap mechanism, we were able to realize an improved TTF ratio and reduce hole accumulation by adding a TTF-assisting material (TTF-AM) in the TTF emitter. The TTF-AM served as the hole transport channel, triggering hole trap and detrap while improving the hole transport character of the emitting layer. Through the process of hole detrapping, the improved hole transport properties balanced carriers and generated more triplet excitons in order to activate the TTF mechanism from low to high current density ranges. By adjusting the TTF-AM, the TTF ratio of the anthracene-based emitter was increased from 5.5/20.1% to 13.4/25.5% (low/high current density), thereby resulting in more than doubled external quantum efficiency at low current density.
{"title":"Stimulated triplet–triplet fusion by carrier trap-detrap mechanism in organic light-emitting diodes","authors":"Kyung Hyung Lee, Jae Min Kim, S. Jeong, Ji‐Ho Baek, Jeongdae Seo, I. Song, Sang Beom Kim, H. Choi, Jun Yeob Lee","doi":"10.1080/15980316.2022.2089750","DOIUrl":"https://doi.org/10.1080/15980316.2022.2089750","url":null,"abstract":"Triplet–triplet fusion (TTF) has been an efficiency-enhancing mechanism in fluorescent organic light-emitting diodes (OLEDs) caused by the collision of two triplet excitons. However, achieving a high TTF ratio in fluorescent OLEDs has been difficult despite device strategies to maximize the triplet exciton density within a narrow recombination zone near the electron blocking layer (EBL) due to charge imbalance and hole accumulation between the TTF type emitter and EBL. Based on a trap-detrap mechanism, we were able to realize an improved TTF ratio and reduce hole accumulation by adding a TTF-assisting material (TTF-AM) in the TTF emitter. The TTF-AM served as the hole transport channel, triggering hole trap and detrap while improving the hole transport character of the emitting layer. Through the process of hole detrapping, the improved hole transport properties balanced carriers and generated more triplet excitons in order to activate the TTF mechanism from low to high current density ranges. By adjusting the TTF-AM, the TTF ratio of the anthracene-based emitter was increased from 5.5/20.1% to 13.4/25.5% (low/high current density), thereby resulting in more than doubled external quantum efficiency at low current density.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44932630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-17DOI: 10.1080/15980316.2022.2089751
Gunel Huseynova, Jae-Hyun Lee, Akpeko Gasonoo, Hyunkoo Lee, Y. Kim, Jang-Sik Lee
ABSTRACT We present the fluorinated hexaazatrinaphthylene derivative, 1,2,3,4,7,8,9,10,13,14,15,16-dodecafluoro-5,6,11,12,17,18-hexaazatrinaphthylene (HATNA-F12), as a new material to replace another hexaazatrinaphthylene molecule, 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN), which is widely used as an intermediate connector and charge generation layer (CGL) in tandem organic light-emitting diodes (OLEDs). Upon comparison with the reference single emitting layer unit OLED, the tandem device with HATNA-F12 CGL had improved current efficiency and external quantum efficiency of 42.1% and 41.7%, respectively. Our results show that HATNA-F12 is an excellent substitute for HAT-CN and has more promising characteristics as a CGL material for applications in tandem OLEDs. When compared to devices with HAT-CN CGL, the green tandem OLEDs with CGL consisting of HATNA-F12 demonstrated improved current efficiency, power efficacy, and external quantum efficiency values, while the change of the CGL material had almost no effect on the operating voltage, current density, and color coordinates of the OLEDs. We confirm that using the newly suggested HATNA-F12 molecule as a CGL in these OLEDs can enhance device efficiency.
{"title":"Efficient tandem organic light-emitting diode with fluorinated hexaazatrinaphthylene charge generation layer","authors":"Gunel Huseynova, Jae-Hyun Lee, Akpeko Gasonoo, Hyunkoo Lee, Y. Kim, Jang-Sik Lee","doi":"10.1080/15980316.2022.2089751","DOIUrl":"https://doi.org/10.1080/15980316.2022.2089751","url":null,"abstract":"ABSTRACT We present the fluorinated hexaazatrinaphthylene derivative, 1,2,3,4,7,8,9,10,13,14,15,16-dodecafluoro-5,6,11,12,17,18-hexaazatrinaphthylene (HATNA-F12), as a new material to replace another hexaazatrinaphthylene molecule, 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN), which is widely used as an intermediate connector and charge generation layer (CGL) in tandem organic light-emitting diodes (OLEDs). Upon comparison with the reference single emitting layer unit OLED, the tandem device with HATNA-F12 CGL had improved current efficiency and external quantum efficiency of 42.1% and 41.7%, respectively. Our results show that HATNA-F12 is an excellent substitute for HAT-CN and has more promising characteristics as a CGL material for applications in tandem OLEDs. When compared to devices with HAT-CN CGL, the green tandem OLEDs with CGL consisting of HATNA-F12 demonstrated improved current efficiency, power efficacy, and external quantum efficiency values, while the change of the CGL material had almost no effect on the operating voltage, current density, and color coordinates of the OLEDs. We confirm that using the newly suggested HATNA-F12 molecule as a CGL in these OLEDs can enhance device efficiency.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49526946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-24DOI: 10.1080/15980316.2022.2077849
Yung-Jun Park
The correlation between the measured luminance of a stimulus and its perceptual brightness, which varies with saturation and color, has been studied extensively. The increase in the colorfulness of the stimulus generates a Helmholtz-Kohlrausch (H-K) effect, which appears ‘bright’. This study aims to quantify the H-K effect of a highly saturated self-luminous display and to apply it to the CAM16 model. It also attempts to quantify the H-K effect by using the ratio of lightness and luminance values obtained from the modified CAM16 model. Future research objectives include the accurate prediction of color attributes to develop a model of high saturation displays in order to compare conventional displays.
{"title":"Determining the color appearance of Helmholtz-Kohlrausch effect for self-emissive displays","authors":"Yung-Jun Park","doi":"10.1080/15980316.2022.2077849","DOIUrl":"https://doi.org/10.1080/15980316.2022.2077849","url":null,"abstract":"The correlation between the measured luminance of a stimulus and its perceptual brightness, which varies with saturation and color, has been studied extensively. The increase in the colorfulness of the stimulus generates a Helmholtz-Kohlrausch (H-K) effect, which appears ‘bright’. This study aims to quantify the H-K effect of a highly saturated self-luminous display and to apply it to the CAM16 model. It also attempts to quantify the H-K effect by using the ratio of lightness and luminance values obtained from the modified CAM16 model. Future research objectives include the accurate prediction of color attributes to develop a model of high saturation displays in order to compare conventional displays.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46083649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-19DOI: 10.1080/15980316.2022.2075042
Jaipal Devesing Girase, S. Mukherjee, Tanwistha Chakrabarti, Sabita Patel, A. Perumal, S. Vaidyanathan
The design of an efficient pure blue emitter to achieve stable, long operating organic light-emitting diode (OLED) devices still poses a significant challenge. Although through phosphorescence and thermally activated delayed fluorescence concepts, efficient and stable monochrome green and red OLEDs can be realized, the design of stable and efficient blue emitter has been a significant challenge. All efforts so far have resulted in severe efficiency roll-off and limited device lifetime. Therefore, developing efficient blue-emitting fluorescence materials with little or no efficiency roll-off is of great importance for commercial display OLEDs. In this context, we have designed and synthesized two pure blue fluorescence light-emitting materials that are thermally stable and have improved photophysical properties: 2-(4″-(1-(4-(tert-butyl)phenyl)-4,5-diphenyl-1H-imidazol-2-yl)-[1,1′:4′,1′′-terphenyl]-4-yl)-1-phenyl-1H-benzo[d]imidazole (PTBIBI) and 2-(4′′-(4,5-diphenyl-1-(3-(trifluoromethyl)phenyl)-1H-imidazol-2-yl)-[1,1′:4′,1′′-terphenyl]-4-yl)-1-phenyl-1H-benzo[d]imidazole (MCFBIBI). These emitters possess a hybrid local and charge-transfer (HLCT) state and have high photoluminescence quantum yields (>90%). The doped devices based on PTBIBI display a reasonably good device performance with the Commission International de l’Eclairage (CIE) coordinates of (0.15, 0.06) in the deep blue region and g maximum luminance of 6559 cd m−2 at a very low turn-on voltage (3.2 V) corresponding to the bandgap value of the blue emitter.
设计高效的纯蓝色发射器以实现稳定、长时间工作的有机发光二极管（OLED）器件仍然是一个重大挑战。尽管通过磷光和热激活延迟荧光的概念，可以实现高效稳定的单色绿色和红色OLED，但设计稳定高效的蓝色发射器一直是一个重大挑战。到目前为止，所有的努力都导致了严重的效率下降和有限的器件寿命。因此，开发效率很低或没有效率衰减的高效蓝光荧光材料对于商业显示器OLED具有重要意义。在这种情况下，我们设计并合成了两种热稳定并改善光物理性能的纯蓝色荧光发光材料：2-（4〃-（1-（4-（叔丁基）苯基）-4,5-二苯基-1H-咪唑-2-基）-[1，1′：4′，1′-三苯基]-4-基）-1-苯基-1H-苯并[d]咪唑（PTBIBI）和2-（4′-（4,5-二苯基-1-（3-（三氟甲基）苯基）-1H-咪唑2-基）-[1，1′：4′，1′′-三苯基]-4-基）-1-苯基-1H-苯并[d]咪唑（MCFBIBI）。这些发射体具有混合的局域和电荷转移（HLCT）状态，并具有高的光致发光量子产率（>90%）。基于PTBIBI的掺杂器件在深蓝色区域显示出相当好的器件性能，国际照明委员会（CIE）坐标为（0.15，0.06），在与蓝色发射器的带隙值相对应的非常低的开启电压（3.2V）下，g最大亮度为6559 cd m−2。
{"title":"Mild donor-π-mild acceptor (mD-π-mA) benzimidazole-based deep blue fluorophores with hybridized local and charge transfer (HLCT) excited states for OLEDs","authors":"Jaipal Devesing Girase, S. Mukherjee, Tanwistha Chakrabarti, Sabita Patel, A. Perumal, S. Vaidyanathan","doi":"10.1080/15980316.2022.2075042","DOIUrl":"https://doi.org/10.1080/15980316.2022.2075042","url":null,"abstract":"The design of an efficient pure blue emitter to achieve stable, long operating organic light-emitting diode (OLED) devices still poses a significant challenge. Although through phosphorescence and thermally activated delayed fluorescence concepts, efficient and stable monochrome green and red OLEDs can be realized, the design of stable and efficient blue emitter has been a significant challenge. All efforts so far have resulted in severe efficiency roll-off and limited device lifetime. Therefore, developing efficient blue-emitting fluorescence materials with little or no efficiency roll-off is of great importance for commercial display OLEDs. In this context, we have designed and synthesized two pure blue fluorescence light-emitting materials that are thermally stable and have improved photophysical properties: 2-(4″-(1-(4-(tert-butyl)phenyl)-4,5-diphenyl-1H-imidazol-2-yl)-[1,1′:4′,1′′-terphenyl]-4-yl)-1-phenyl-1H-benzo[d]imidazole (PTBIBI) and 2-(4′′-(4,5-diphenyl-1-(3-(trifluoromethyl)phenyl)-1H-imidazol-2-yl)-[1,1′:4′,1′′-terphenyl]-4-yl)-1-phenyl-1H-benzo[d]imidazole (MCFBIBI). These emitters possess a hybrid local and charge-transfer (HLCT) state and have high photoluminescence quantum yields (>90%). The doped devices based on PTBIBI display a reasonably good device performance with the Commission International de l’Eclairage (CIE) coordinates of (0.15, 0.06) in the deep blue region and g maximum luminance of 6559 cd m−2 at a very low turn-on voltage (3.2 V) corresponding to the bandgap value of the blue emitter.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42788373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-09DOI: 10.1080/15980316.2022.2070291
Byeongmoon Lee, Hyeon Cho, Sujin Jeong, Jae-Jun Yoon, Dongju Jang, Dong Keon Lee, Dahyun Kim, Seungjun Chung, Yongtaek Hong
Stretchable hybrid electronics (SHE) that combine high-performance rigid electronic devices with stretchable interconnects offer a facile route for accessing and processing bio-signals and human interactions. Incorporated with sensors and wireless communications, SHE achieves novel applications such as biomedical diagnosis, skin prosthetics, and robotic skin. The implementation of reliable SHE requires the comprehensive development of stretchable electrodes, bonding techniques, and strain-engineered integration schemes. This review covers the recent development of enabling technologies for SHE in terms of materials, structures, and system engineering. We introduce various strategies for stretchable interconnects based on novel materials and structural designs. In particular, we classify SHE into three groups based on strain-relief configurations: thin-film devices on rigid islands, rigid devices with stretchable bridges, and flexible circuits with stretchable bridges. Appropriate methods for substrates, stretchable interconnects, and bonding between rigid and soft components and their pros and cons are extensively discussed. We also explore state-of-the-art SHE in advanced human-machine interfaces and discuss the challenges and prospects for future directions.
{"title":"Stretchable hybrid electronics: combining rigid electronic devices with stretchable interconnects into high-performance on-skin electronics","authors":"Byeongmoon Lee, Hyeon Cho, Sujin Jeong, Jae-Jun Yoon, Dongju Jang, Dong Keon Lee, Dahyun Kim, Seungjun Chung, Yongtaek Hong","doi":"10.1080/15980316.2022.2070291","DOIUrl":"https://doi.org/10.1080/15980316.2022.2070291","url":null,"abstract":"Stretchable hybrid electronics (SHE) that combine high-performance rigid electronic devices with stretchable interconnects offer a facile route for accessing and processing bio-signals and human interactions. Incorporated with sensors and wireless communications, SHE achieves novel applications such as biomedical diagnosis, skin prosthetics, and robotic skin. The implementation of reliable SHE requires the comprehensive development of stretchable electrodes, bonding techniques, and strain-engineered integration schemes. This review covers the recent development of enabling technologies for SHE in terms of materials, structures, and system engineering. We introduce various strategies for stretchable interconnects based on novel materials and structural designs. In particular, we classify SHE into three groups based on strain-relief configurations: thin-film devices on rigid islands, rigid devices with stretchable bridges, and flexible circuits with stretchable bridges. Appropriate methods for substrates, stretchable interconnects, and bonding between rigid and soft components and their pros and cons are extensively discussed. We also explore state-of-the-art SHE in advanced human-machine interfaces and discuss the challenges and prospects for future directions.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44990575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-11DOI: 10.1080/15980316.2022.2061056
O. Kwon, Dongjin Kim, Mijin Kim, Honyeon Lee
High-performance tandem quantum-dot light-emitting diodes (QLEDs) are needed for practical next-generation displays. This study designed a high-performance interconnecting layer (ICL) that combines QLED units into tandem QLEDs and demonstrated its effectiveness. The ICLs were designed for charge generation, for interconnecting QLEDs, and for protecting the underlayers from damage during upper-layer fabrication. Using the ICLs with a first layer of thermally evaporated WO3 and a second layer of sputtered SnO2 or zinc tin oxide, the required roles of the ICL were fulfilled. The current efficiencies of tandem QLEDs using a double-layer ICL were about triple those of a single QLED, an improvement from 26 cd/A for a single QLED to 82 cd/A for a tandem QLED connecting two QLED units. This current efficiency was much higher than previously reported values for tandem QLEDs connecting QLED units with CdSe/ZnS green quantum dots and ZnO electron-transport layers. The method presented here will contribute to the practical application of QLEDs for large TVs and light-illumination devices.
{"title":"High-performance tandem CdSe/ZnS quantum-dot light-emitting diodes with a double-layer interconnecting layer composed of thermally evaporated and sputtered metal oxides","authors":"O. Kwon, Dongjin Kim, Mijin Kim, Honyeon Lee","doi":"10.1080/15980316.2022.2061056","DOIUrl":"https://doi.org/10.1080/15980316.2022.2061056","url":null,"abstract":"High-performance tandem quantum-dot light-emitting diodes (QLEDs) are needed for practical next-generation displays. This study designed a high-performance interconnecting layer (ICL) that combines QLED units into tandem QLEDs and demonstrated its effectiveness. The ICLs were designed for charge generation, for interconnecting QLEDs, and for protecting the underlayers from damage during upper-layer fabrication. Using the ICLs with a first layer of thermally evaporated WO3 and a second layer of sputtered SnO2 or zinc tin oxide, the required roles of the ICL were fulfilled. The current efficiencies of tandem QLEDs using a double-layer ICL were about triple those of a single QLED, an improvement from 26 cd/A for a single QLED to 82 cd/A for a tandem QLED connecting two QLED units. This current efficiency was much higher than previously reported values for tandem QLEDs connecting QLED units with CdSe/ZnS green quantum dots and ZnO electron-transport layers. The method presented here will contribute to the practical application of QLEDs for large TVs and light-illumination devices.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46559184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-08DOI: 10.1080/15980316.2022.2039790
C. Yoon, Aram Moon, Heesun Yang, Jiwan Kim
We demonstrate the high efficiency of quantum dot light-emitting diodes (QLEDs) that consist of a mixed layer of SnO2 nanoparticles (NPs) and quantum dots (QDs). A stable mixture of SnO2 NPs and QDs is prepared in chlorobenzene and then applied to QLEDs with no separate electron transport layer (ETL). QLEDs with such a simplified structure produce a maximum luminance of 142,855 cd/m2, an EQE of 9.42%, and a current efficiency of 41.18 cd/A that result from the improved charge balance of the mixed layer. This produces one of the best device performances of QLEDs with a non-ZnO inorganic ETL, clearly indicating the remarkable promise of using SnO2 NPs as an inorganic ETL for QLEDs. Moreover, the reduction of fabrication steps in this solution-based process proves advantageous to next-generation display technology.
{"title":"Highly efficient electroluminescence devices with a mixed layer of SnO2 and colloidal quantum dots","authors":"C. Yoon, Aram Moon, Heesun Yang, Jiwan Kim","doi":"10.1080/15980316.2022.2039790","DOIUrl":"https://doi.org/10.1080/15980316.2022.2039790","url":null,"abstract":"We demonstrate the high efficiency of quantum dot light-emitting diodes (QLEDs) that consist of a mixed layer of SnO2 nanoparticles (NPs) and quantum dots (QDs). A stable mixture of SnO2 NPs and QDs is prepared in chlorobenzene and then applied to QLEDs with no separate electron transport layer (ETL). QLEDs with such a simplified structure produce a maximum luminance of 142,855 cd/m2, an EQE of 9.42%, and a current efficiency of 41.18 cd/A that result from the improved charge balance of the mixed layer. This produces one of the best device performances of QLEDs with a non-ZnO inorganic ETL, clearly indicating the remarkable promise of using SnO2 NPs as an inorganic ETL for QLEDs. Moreover, the reduction of fabrication steps in this solution-based process proves advantageous to next-generation display technology.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49608472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-10DOI: 10.1080/15980316.2022.2029778
Jongsu Oh, Jin-Ho Kim, Eun Kyo Jung, Jongsul Min, Hwarim Im, Yong-Sang Kim
In this study, we have investigated the operation robustness of a p-type low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT)-based micro light-emitting diode (µLED) pixel circuit adopting pulse width modulation (PWM) under circuit component fluctuations. The wavelength shift of µLEDs, depending on the current density, was suppressed by implementing PWM. The PWM pixel circuit controlled the emission time with constant µLED current in the simulated and measured results. In addition, the wavelength shift was suppressed below 0.48% within the 10-bit grayscale range. Furthermore, the component tolerance of the pixel circuit was investigated by simulating the error rate of µLED emission time with varying threshold voltage, mobility, subthreshold swing, and capacitance. The pixel circuit exhibited a robust operation with a maximum error rate of 4.0% under a component fluctuation of ±10%. Consequently, the µLED pixel circuit adopting PWM suppressed the wavelength shift of µLEDs and demonstrated robust circuit operation under component fluctuation.
{"title":"Investigation on operation robustness of p-type low-temperature polycrystalline silicon thin-film transistor-based micro light-emitting diode pixel circuit using pulse width modulation under component fluctuation","authors":"Jongsu Oh, Jin-Ho Kim, Eun Kyo Jung, Jongsul Min, Hwarim Im, Yong-Sang Kim","doi":"10.1080/15980316.2022.2029778","DOIUrl":"https://doi.org/10.1080/15980316.2022.2029778","url":null,"abstract":"In this study, we have investigated the operation robustness of a p-type low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT)-based micro light-emitting diode (µLED) pixel circuit adopting pulse width modulation (PWM) under circuit component fluctuations. The wavelength shift of µLEDs, depending on the current density, was suppressed by implementing PWM. The PWM pixel circuit controlled the emission time with constant µLED current in the simulated and measured results. In addition, the wavelength shift was suppressed below 0.48% within the 10-bit grayscale range. Furthermore, the component tolerance of the pixel circuit was investigated by simulating the error rate of µLED emission time with varying threshold voltage, mobility, subthreshold swing, and capacitance. The pixel circuit exhibited a robust operation with a maximum error rate of 4.0% under a component fluctuation of ±10%. Consequently, the µLED pixel circuit adopting PWM suppressed the wavelength shift of µLEDs and demonstrated robust circuit operation under component fluctuation.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2022-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41770344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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