Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes
Abstract
:1. Introduction
2. Results and Discussion
2.1. Synthesis
2.2. Thermal Properties
2.3. Photophysical and Electrochemical Properties
2.4. Device Characteristics
3. Materials and Methods
3.1. General Procedures
3.2. Synthetic Procedures
3.2.1. 4-Bromo-N′-(4-bromobenzoyl)benzohydrazide (1)
3.2.2. 2,5-Bis(4-bromophenyl)-1,3,4-oxadiazole (2)
3.2.3. 2-(4-Bromophenyl)-5-phenyl-1,3,4-oxadiazole (4)
3.2.4. 2,5-Bis(4-(9,9-diphenyl-9,10-dihydroacridine)phenyl)-1,3,4-oxadiazole (2DPAc-OXD)
3.2.5. 2-(4-(9,9-Diphenyl-9,10-dihydroacridine)phenyl)-1,3,4-oxadiazole (DPAc-OXD)
3.2.6. 2,5-Bis(4-(10H-phenothiazin-10-yl)-1,3,4-oxadizole (2PTZ-OXD)
3.2.7. 2-(4-(10H-phenothiazin-10-yl)-1,3,4-oxadiazole(PTZ-OXD)
3.3. OLED Fabrication and Characterization
4. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Sample Availability: Samples of the compounds are not available from the authors. |
Dopant | Td a (°C) | UV-vis b (nm) | PL max c (nm) | HOMO d (eV) | LUMO e (eV) | Eg f (eV) | ET g (eV) |
---|---|---|---|---|---|---|---|
PTZ-OXD 2PTZ-OXD DPAc-OXD 2DPAc-OXD | 358 419 375 455 | 376 384 396 402 | 500 512 435 442 | −5.48 −5.48 −5.69 −5.68 | −2.18 −2.25 −2.56 −2.60 | 3.30 3.23 3.13 3.08 | 2.48 2.42 2.85 2.81 |
Calculation Values | PTZ-OXD | 2PTZ-OXD | DPAc-OXD | 2DPAc-OXD |
---|---|---|---|---|
S1 (eV) a T1 (eV) b ΔEST (eV) c D-A rotation(°) HOMO (eV) LUMO (eV) | 3.71 3.36 0.35 77.05 −5.975 −2.185 | 3.63 3.34 0.29 78.91 −5.485 −2.255 | 3.83 3.37 0.46 81.26 −5.695 −2.565 | 3.78 3.34 0.44 81.70 −5.685 −2.605 |
Device properties | PTZ-OXD | 2PTZ-OXD | DPAc-OXD | 2DPAc-OXD |
---|---|---|---|---|
Turn on voltage (V) | 4.4 a 6.0 b | 4.2 a 5.6 b | 4.1 a 6.0 b | 4.1 a 6.2 b |
Driving voltage (V) | 6.8 a | 5.9 a | 7.6 a | 7.5 a |
Current (mA) | 0.05 a 0.05 b | 0.03 a 0.03 b | 0.04 a 0.06 b | 0.05 a 0.10 b |
Current efficiency (cd/A) | 5.03 a 4.97 b | 9.20 a 10.10 b | 1.30 a 0.72 b | 1.28 a 0.66 b |
Power efficiency (Lm/W) | 3.59 a 2.60 b | 6.88 a 5.67 b | 0.99 a 0.38 b | 0.98 a 0.33 b |
EQE (%) | 1.94 a | 3.38 a | 1.84 a | 1.81 a |
2.26 b | 3.99 b | 1.08 b | 0.88 b | |
Luminance (at 1000 cd/m2) | 1008 | 1020 | 1029 | 992 |
CIE (x,y) | (0.38, 0.50) a (0.43, 0.14) b | (0.40, 0.53) a (0.31, 0.49) b | (0.16, 0.12) a (0.18, 0.12) b | (0.17, 0.14) a (0.18, 0.15) b |
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Wu, Q.; Braveenth, R.; Zhang, H.Q.; Bae, I.-J.; Kim, M.; Chai, K.Y. Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes. Molecules 2018, 23, 843. https://doi.org/10.3390/molecules23040843
Wu Q, Braveenth R, Zhang HQ, Bae I-J, Kim M, Chai KY. Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes. Molecules. 2018; 23(4):843. https://doi.org/10.3390/molecules23040843
Chicago/Turabian StyleWu, Qiong, Ramanaskanda Braveenth, Heng Qiang Zhang, Il-Ji Bae, Miyoung Kim, and Kyu Yun Chai. 2018. "Oxadiazole-Based Highly Efficient Bipolar Fluorescent Emitters for Organic Light-Emitting Diodes" Molecules 23, no. 4: 843. https://doi.org/10.3390/molecules23040843