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Siddiqui I, Kumar S, Tsai YF, Gautam P, Shahnawaz, Kesavan K, Lin JT, Khai L, Chou KH, Choudhury A, Grigalevicius S, Jou JH. Status and Challenges of Blue OLEDs: A Review. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2521. [PMID: 37764550 PMCID: PMC10536903 DOI: 10.3390/nano13182521] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023]
Abstract
Organic light-emitting diodes (OLEDs) have outperformed conventional display technologies in smartphones, smartwatches, tablets, and televisions while gradually growing to cover a sizable fraction of the solid-state lighting industry. Blue emission is a crucial chromatic component for realizing high-quality red, green, blue, and yellow (RGBY) and RGB white display technologies and solid-state lighting sources. For consumer products with desirable lifetimes and efficiency, deep blue emissions with much higher power efficiency and operation time are necessary prerequisites. This article reviews over 700 papers covering various factors, namely, the crucial role of blue emission for full-color displays and solid-state lighting, the performance status of blue OLEDs, and the systematic development of fluorescent, phosphorescent, and thermally activated delayed fluorescence blue emitters. In addition, various challenges concerning deep blue efficiency, lifetime, and approaches to realizing deeper blue emission and higher efficacy for blue OLED devices are also described.
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Affiliation(s)
- Iram Siddiqui
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Sudhir Kumar
- Institute for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Yi-Fang Tsai
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Prakalp Gautam
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Shahnawaz
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kiran Kesavan
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Jin-Ting Lin
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Luke Khai
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kuo-Hsien Chou
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Abhijeet Choudhury
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Saulius Grigalevicius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, LT-50254 Kaunas, Lithuania
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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Beresneviciute R, Gautam P, Nagar MR, Krucaite G, Tavgeniene D, Jou JH, Grigalevicius S. Naphtalimide-Based Bipolar Derivatives Enabling High-Efficiency OLEDs. Molecules 2023; 28:6027. [PMID: 37630279 PMCID: PMC10458866 DOI: 10.3390/molecules28166027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/03/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Organic light-emitting diodes (OLEDs) have revolutionized the world of technology, making significant contributions to enhancing our everyday lives. With their exceptional display and lighting capabilities, OLEDs have become indispensable in various industries such as smartphones, tablets, televisions, and automotives. They have emerged as a dominant technology, inspiring continuous advancements, and improvements. Taking inspiration from the remarkable advancements in OLED advancements, we have successfully developed naphtalimide-based compounds, namely RB-08, RB-09, RB-10, and RB-11. These compounds exhibit desirable characteristics such as a wide bandgap, high decomposition temperatures (306-366 °C), and very high glass transition temperatures (133-179 °C). Leveraging these exceptional properties, we have harnessed these compounds as green emitters in the aforementioned devices. Among the various fabricated OLEDs, the one incorporating the RB-11 emitter has exhibited superior performance. This specific configuration achieved maximum power efficacy of 7.7 lm/W, current efficacy of 7.9 cd/A, and external quantum efficiency of 3.3%. These results highlight the outstanding capabilities of our synthesized emitter and its potential for further advancements in the field.
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Affiliation(s)
- Raminta Beresneviciute
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
| | - Prakalp Gautam
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Mangey Ram Nagar
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Gintare Krucaite
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
| | - Daiva Tavgeniene
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Saulius Grigalevicius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
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Tsai PC, Cheng MH, Peng BH, Jou JH, Cheng YH, Ku YC, Chiu HY, Chou ML, Yeh PT. Permissible viewing times of educational projector and TV. Heliyon 2023; 9:e15522. [PMID: 37180913 PMCID: PMC10173401 DOI: 10.1016/j.heliyon.2023.e15522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Projectors have become one major medium in modern teaching, with large area-size displays emerging as an alternative. What concerns the general public is whether such eLearning would impose threat on eyes, by noting blue enriched white light to be hazardous to retina and else. Especially, little was known about their permissible viewing time under a certain viewing clarity. We had hence carried out a quantitative study with the use of a blue-hazard quantification spectrometer to determine the permissible viewing time when using a projector and a large size TV screen for displaying. Surprisingly, the large TV screen could permit a much longer viewing time, meaning which is more eye-friendly. It is plausibly because its resolution is much higher than that of the projector. Two dilemmas were observed in such eLearning; those sitting in the front would suffer a much higher illuminance, leading to a much shorter viewing time, while those sitting in the back would need a far much larger font size to see clearly. To ensure both viewing clarity and a sufficiently long permissible viewing time, orange text on black background is suggested to replace the defaulted black text on white background. The permissible viewing time could hence drastically increase from 1.3 to 83 h at 2 m by viewing a 30 pt font for the TV and from 0.4 to 54 h for the projection. At 6 m, the permissible viewing time was increased from 12 to 236 h for the TV and from 3 to 160 h for the projection, based on a viewable 94 pt font. These results may help educators and other e-display users to wisely apply the display tools with safety.
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Affiliation(s)
- Pei-Chung Tsai
- Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan
| | - Ming-Hui Cheng
- Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan
| | - Bo-Hsun Peng
- Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering, National Tsing Hua University, Hsin-Chu, Taiwan
- Corresponding author.
| | | | - Yi-Chen Ku
- Shu-Guang Girls' Senior High School, Hsin-Chu, Taiwan
| | - Hsin-Ya Chiu
- Shu-Guang Girls' Senior High School, Hsin-Chu, Taiwan
| | - Ming-Li Chou
- Shu-Guang Girls' Senior High School, Hsin-Chu, Taiwan
| | - Po-Ting Yeh
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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Gautam P, Shahnawaz, Siddiqui I, Blazevicius D, Krucaite G, Tavgeniene D, Jou JH, Grigalevicius S. Bifunctional Bicarbazole-Benzophenone-Based Twisted Donor-Acceptor-Donor Derivatives for Deep-Blue and Green OLEDs. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1408. [PMID: 37110993 PMCID: PMC10146648 DOI: 10.3390/nano13081408] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 04/07/2023] [Accepted: 04/15/2023] [Indexed: 08/27/2023]
Abstract
Organic light-emitting diodes (OLEDs) have played a vital role in showing tremendous technological advancements for a better lifestyle, due to their display and lighting technologies in smartphones, tablets, television, and automotive industries. Undoubtedly, OLED is a mainstream technology and, inspired by its advancements, we have designed and synthesized the bicarbazole-benzophenone-based twisted donor-acceptor-donor (D-A-D) derivatives, namely DB13, DB24, DB34, and DB43, as bi-functional materials. These materials possess high decomposition temperatures (>360 °C) and glass transition temperatures (~125 °C), a high photoluminescence quantum yield (>60%), wide bandgap (>3.2 eV), and short decay time. Owing to their properties, the materials were utilized as blue emitters as well as host materials for deep-blue and green OLEDs, respectively. In terms of the blue OLEDs, the emitter DB13-based device outperformed others by showing a maximum EQE of 4.0%, which is close to the theoretical limit of fluorescent materials for a deep-blue emission (CIEy = 0.09). The same material also displayed a maximum power efficacy of 45 lm/W as a host material doped with a phosphorescent emitter Ir(ppy)3. Furthermore, the materials were also utilized as hosts with a TADF green emitter (4CzIPN) and the device based on DB34 displayed a maximum EQE of 11%, which may be attributed to the high quantum yield (69%) of the host DB34. Therefore, the bi-functional materials that are easily synthesized, economical, and possess excellent characteristics are expected to be useful in various cost-effective and high-performance OLED applications, especially in displays.
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Affiliation(s)
- Prakalp Gautam
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Shahnawaz
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Iram Siddiqui
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Dovydas Blazevicius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
| | - Gintare Krucaite
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
| | - Daiva Tavgeniene
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Guangfu Rd., East District, Hsinchu 30013, Taiwan
| | - Saulius Grigalevicius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
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