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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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Tavgeniene D, Zhang B, Grigalevicius S. Di(arylcarbazole) Substituted Oxetanes as Efficient Hole Transporting Materials with High Thermal and Morphological Stability for OLEDs. Molecules 2023; 28:molecules28052282. [PMID: 36903529 PMCID: PMC10005742 DOI: 10.3390/molecules28052282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/25/2023] [Accepted: 02/25/2023] [Indexed: 03/05/2023] Open
Abstract
A group of di(arylcarbazole)-substituted oxetanes has been prepared in Suzuki reactions by using the key starting material 3,3-di[3-iodocarbazol-9-yl]methyloxetane and various boronic acids (fluorophenylboronic acid, phenylboronic acid or naphthalene-1-boronic acid). Full characterization of their structure has been presented. The low molar mass compounds represent materials having high thermal stability with 5% mass loss thermal degradation temperatures in the range of 371-391 °C. Glass transition temperatures of the materials are also very high and range from 107 °C to 142 °C, which is a big advantage for formation of stable amorphous layers for optoelectronic devices, i.e., organic light emitting diodes. Hole transporting properties of the prepared materials were confirmed in formed organic light emitting diodes with tris(quinolin-8-olato)aluminium (Alq3) as a green emitter, which also served as an electron transporting layer. In the device's materials, 3,3-di[3-phenylcarbazol-9-yl]methyloxetane (5) and 3,3-di[3-(1-naphthyl)carbazol-9-yl]methyloxetane (6) demonstrated superior hole transporting properties than that of material 3,3-di[3-(4-flourophenyl)carbazol-9-yl]methyloxetane (4) based device. When material 5 was used in the device structure, the OLED demonstrated rather low turn-on voltage of 3.7 V, luminous efficiency of 4.2 cd/A, power efficiency of 2.6 lm/W and maximal brightness exceeding 11670 cd/m2. HTL of 6 based device also showed exclusive OLED characteristics. The device was characterized by turn-on voltage of 3.4 V, maximum brightness of 13193 cd/m2, luminous efficiency of 3.8 cd/A and power efficiency of 2.6 lm/W. An additional hole injecting-transporting layer (HI-TL) of PEDOT considerably improved functions of the device with HTL of compound 4. The modified OLED with a layer of the derivative 4 demonstrated exclusive characteristics with turn-on voltage of 3.9 V, high luminous efficiency of 4.7 cd/A, power efficiency of 2.6 lm/W and maximal brightness exceeding 21,000 cd/m2. These observations confirmed that the prepared materials have a big potential in the field of optoelectronics.
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Affiliation(s)
- Daiva Tavgeniene
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
- Correspondence: (D.T.); (S.G.)
| | - Baohua Zhang
- Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials & Devices, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China
| | - Saulius Grigalevicius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Plentas 19, LT50254 Kaunas, Lithuania
- Correspondence: (D.T.); (S.G.)
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Filipek P, Karoń K, Hellwig H, Szłapa-Kula A, Filapek M. The Role of Intermolecular Interaction on Aggregation-Induced Emission Phenomenon and OLED Performance. MATERIALS (BASEL, SWITZERLAND) 2022; 15:ma15238525. [PMID: 36500022 PMCID: PMC9737140 DOI: 10.3390/ma15238525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/18/2022] [Accepted: 11/26/2022] [Indexed: 06/01/2023]
Abstract
In this work, the role of intermolecular interaction on the aggregation-induced emission (AIE) phenomenon and organic light-emitting diodes' (OLEDs) performance was investigated. During the research, a group of compounds consisting of the (-CH=C(CN)(COOR)) moiety with identical energy parameters was designed using the DFT approach and successfully synthesized. The optical, electrochemical, and aggregation-induced emission properties were studied. The aggregation-induced emission of compounds has been studied in the mixture of MeCN (as a good solvent) and water (as a poor solvent) with different water fractions ranging from 0% to 99%. Moreover, the time dependence on the AIE feature was also evaluated. Thanks to their molecular structures, almost identical behavior of these substances in dilute solutions was observed. For molecules that exhibit the strong AIE phenomenon, emission efficiency increases rapidly during aggregation. What is also very interesting is it has been shown that by introducing an appropriate substituent, one can control the degree of intermolecular interactions and "control" the length of the emitted wave. Finally, OLEDs were fabricated by the spin-coating/evaporation hybrid method. Devices showed green-blueish electroluminescence (CIE coordinates: 0.107, 0.165) with maximum luminance reaching 25 cd m-2 and EQE reaching 2%.
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Affiliation(s)
- Patrycja Filipek
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna 9, 40-007 Katowice, Poland
| | - Krzysztof Karoń
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M. Strzody 9, 44-100 Gliwice, Poland
| | - Hubert Hellwig
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna 9, 40-007 Katowice, Poland
| | - Agata Szłapa-Kula
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna 9, 40-007 Katowice, Poland
| | - Michał Filapek
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna 9, 40-007 Katowice, Poland
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Analysis on the Mechanical Behavior of Flexible Screens. MATERIALS 2022; 15:ma15082829. [PMID: 35454523 PMCID: PMC9032455 DOI: 10.3390/ma15082829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 02/01/2023]
Abstract
Recently, flexible organic light-emitting devices (OLEDs) have become more and more popular. However, the force distribution and deformation are very complex during the bending process, and it is difficult to analyze the stress and strain by theoretical analysis and direct experiment. In this paper, finite element analysis of the bending model for the flexible screen was performed. For common U-shaped bending, it was shown that the maximum Mises stress increases rapidly as the bending radius decreases, and the redistribution of the tensile zone and the compression zone should be the key to the layer material selection. The results were verified by an imaging experiment. Further, a water-drop-shaped bending mode was analyzed to reduce the risk of structure failure.
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