Skip to main content
SpringerLink
Log in

High-efficiency inkjet-printed quantum-dot light-emitting diode enabled by solvent-resistant hole transport materials with high surface energy and extended conjugation

通过具有高表面能和延长共轭链段的耐溶剂空穴传输材料实现高效喷墨打印QLED

  • Articles
  • Published:
Science China Materials Aims and scope Submit manuscript

  • 1 Altmetric

Abstract

Quantum-dot light-emitting diodes (QLEDs) prepared using the solution method have great potential in printed displays, particularly when combined with inkjet printing. The surface energy of the lower film plays a crucial role in the spreading of the upper film in QLEDs. High surface energy promotes close contact between different functional film layers and reduces leakage currents. However, cross-linkable hole transport materials (HTMs) with low surface energies are unsuitable for inkjet printing. Herein, a cross-linkable HTM and its polymer derivative were fabricated using a molecular design. The new polymer poly 9-(4-(ethoxymethyl)phenyl)-3-(7-(9-(4-((hexa-2,4-diyn-1-yloxy)methyl)-phenyl)-9H-carbazol-3-yl)-9,9-dimethyl-9H-fluoren-2-yl)-9H-carbazole (PDA-FLCZ) is synthesized via the polymerization of 3,3′-(9,9-dimethyl-9H-fluorene-2,7-diyl)bis[9-(4-(prop-2-yn-1-yloxy)methyl)phenyl]-9H-carbazole (DA-FLCZ). For the new HTM, stable network structures can be formed at low cross-linking temperatures using two cross-linking strategies, in-situ photothermal cross-linking and thermal cross-linking after prepolymerization, exhibiting excellent solvent resistance and high surface energy. By optimizing the cross-linking process, the cross-linked PDA-FLCZ achieves higher hole mobility and lower trap density, resulting in a maximum external quantum efficiency (EQE) of 17.59% for spin-coated QLEDs, which is 23% higher than that of the device based on DA-FLCZ (14.25%). Moreover, the inkjet-printed QLEDs based on the cross-linked PDA-FLCZ demonstrate a maximum EQE of 15.28%, which is close to 90% of the value of its spin-coated devices.

摘要

量子点发光二极管(QLED)溶液法制备的特点和喷墨打印高度契合, 在印刷显示器领域展现出巨大的应用潜力. 制作QLED器件时, 下层薄膜的表面能对上层薄膜的铺展起着至关重要的作用, 高表面能可以促进不同功能膜层之间的紧密接触并减少漏电流. 然而, 已报道的交联空穴传输材料(HTM)低的表面能不利于喷墨打印. 在此, 我们通过分子设计开发了一种可交联HTM及其聚合物, 新的聚合物命名为[9-(4-(乙氧基甲基)苯基)-3-(7-(9-(4-(己炔基)乙氧基甲基)苯基)-9H-咔唑-3-基)-9H-芴]-9H-咔唑(PDA-FLCZ), 由3,3′-(9,9-二甲基-9H-芴-2,7-二基)双[9-(4-(丙-2-炔-1-氧基)甲基)苯基]-9H-咔唑(DA-FLCZ)聚合得到. 这种新型HTM采用原位光热交联和预聚后热交联两种交联策略, 都可以在较低的交联温度下形成稳定的网络结构, 具有优异的耐溶剂性和较高的表面能. 通过优化交联工艺, 交联PDA-FLCZ薄膜实现了更高的空穴迁移率和更低的陷阱密度, 其对应的旋涂QLED器件的最大外量子效率(EQE)达到17.59%, 比基于DA-FLCZ的器件(14.25%)高出23%. 此外, 基于交联PDA-FLCZ的喷墨打印QLED显示出15.28%的最大EQE, 接近其旋涂器件值的90%.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

References

  1. Xiang C, Wu L, Lu Z, et al. High efficiency and stability of ink-jet printed quantum dot light emitting diodes. Nat Commun, 2020, 11: 1646

    Article  CAS  Google Scholar 

  2. Zhao Q, Han R, Marshall AR, et al. Colloidal quantum dot solar cells: Progressive deposition techniques and future prospects on large-area fabrication. Adv Mater, 2022, 34: 2107888

    Article  CAS  Google Scholar 

  3. Zhao J, Chen L, Li D, et al. Large-area patterning of full-color quantum dot arrays beyond 1000 pixels per inch by selective electrophoretic deposition. Nat Commun, 2021, 12: 4603

    Article  CAS  Google Scholar 

  4. Deng Y, Peng F, Lu Y, et al. Solution-processed green and blue quantum-dot light-emitting diodes with eliminated charge leakage. Nat Photon, 2022, 16: 505–511

    Article  CAS  Google Scholar 

  5. Kim T, Kim KH, Kim S, et al. Efficient and stable blue quantum dot light-emitting diode. Nature, 2020, 586: 385–389

    Article  CAS  Google Scholar 

  6. Dai X, Zhang Z, Jin Y, et al. Solution-processed, high-performance light-emitting diodes based on quantum dots. Nature, 2014, 515: 96–99

    Article  CAS  Google Scholar 

  7. Dai X, Deng Y, Peng X, et al. Quantum-dot light-emitting diodes for large-area displays: Towards the dawn of commercialization. Adv Mater, 2017, 29: 1607022

    Article  Google Scholar 

  8. Lee KH, Han CY, Kang HD, et al. Highly efficient, color-reproducible full-color electroluminescent devices based on red/green/blue quantum dot-mixed multilayer. ACS Nano, 2015, 9: 10941–10949

    Article  CAS  Google Scholar 

  9. Mashford BS, Stevenson M, Popovic Z, et al. High-efficiency quantum-dot light-emitting devices with enhanced charge injection. Nat Photon, 2013, 7: 407–412

    Article  CAS  Google Scholar 

  10. Supran GJ, Shirasaki Y, Song KW, et al. QLEDs for displays and solidstate lighting. MRS Bull, 2013, 38: 703–711

    Article  Google Scholar 

  11. Yang Z, Gao M, Wu W, et al. Recent advances in quantum dot-based light-emitting devices: Challenges and possible solutions. Mater Today, 2019, 24: 69–93

    Article  Google Scholar 

  12. Choi MK, Yang J, Kang K, et al. Wearable red–green–blue quantum dot light-emitting diode array using high-resolution intaglio transfer printing. Nat Commun, 2015, 6: 7149

    Article  CAS  Google Scholar 

  13. Wei C, Su W, Li J, et al. A universal ternary-solvent-ink strategy toward efficient inkjet-printed perovskite quantum dot light-emitting diodes. Adv Mater, 2022, 34: 2107798

    Article  CAS  Google Scholar 

  14. Yang Z, Lin G, Bai J, et al. Inkjet-printed blue InP/ZnS/ZnS quantum dot light-emitting diodes. Chem Eng J, 2022, 450: 138413

    Article  CAS  Google Scholar 

  15. Xie L, Yang J, Zhao W, et al. High-performance inkjet-printed blue QLED enabled by crosslinked and intertwined hole transport layer. Adv Opt Mater, 2022, 10: 2200935

    Article  CAS  Google Scholar 

  16. Chen M, Xie L, Wei C, et al. High performance inkjet-printed QLEDs with 18.3% EQE: Improving interfacial contact by novel halogen-free binary solvent system. Nano Res, 2021, 14: 4125–4131

    Article  CAS  Google Scholar 

  17. Tseng ZL, Chen LC, Chao LW, et al. Aggregation control, surface passivation, and optimization of device structure toward near-infrared perovskite quantum-dot light-emitting diodes with an EQE up to 15.4%. Adv Mater, 2022, 34: 2109785

    Article  CAS  Google Scholar 

  18. Tang P, Xie L, Xiong X, et al. Realizing 22.3% EQE and 7-fold lifetime enhancement in QLEDs via blending polymer TFB and cross-linkable small molecules for a solvent-resistant hole transport layer. ACS Appl Mater Interfaces, 2020, 12: 13087–13095

    Article  CAS  Google Scholar 

  19. Yi YQQ, Yang J, Xie L, et al. Linear cross-linkers enabling photothermally cured hole transport layer for high-performance quantum dots light-emitting diodes with ultralow efficiency roll-off. Chem Eng J, 2022, 439: 135702

    Article  CAS  Google Scholar 

  20. Zhao W, Xie L, Yi YQQ, et al. Optimizing the central steric hindrance of cross-linkable hole transport materials for achieving highly efficient RGB QLEDs. Mater Chem Front, 2020, 4: 3368–3377

    Article  CAS  Google Scholar 

  21. Yi YQQ, Qi D, Wei H, et al. Molecular design of diazo compound for carbene-mediated cross-linking of hole-transport polymer in QLED with reduced energy barrier and improved charge balance. ACS Appl Mater Interfaces, 2022, 14: 39149–39158

    Article  CAS  Google Scholar 

  22. Yi YQQ, Su W. Cross-linking strategies for hole transport/emissive layers in quantum-dot light-emitting diodes. Mater Chem Front, 2023, 7: 6130–6140

    Article  CAS  Google Scholar 

  23. Xiong X, Wei C, Xie L, et al. Realizing 17.0% external quantum efficiency in red quantum dot light-emitting diodes by pursuing the ideal inkjet-printed film and interface. Org Electron, 2019, 73: 247–254

    Article  CAS  Google Scholar 

  24. Park SR, Kang JH, Ahn DA, et al. A cross-linkable hole transport material having improved mobility through a semi-interpenetrating polymer network approach for solution-processed green PHOLEDs. J Mater Chem C, 2018, 6: 7750–7758

    Article  CAS  Google Scholar 

  25. Khan Q, Subramanian A, Ahmed I, et al. Overcoming the electroluminescence efficiency limitations in quantum-dot light-emitting diodes. Adv Opt Mater, 2019, 7: 9

    Article  Google Scholar 

  26. Hu W, Zhang Z, Cui J, et al. Influence of π-bridge conjugation on the electrochemical properties within hole transporting materials for perovskite solar cells. Nanoscale, 2017, 9: 12916–12924

    Article  CAS  Google Scholar 

  27. Zhang W, Smith J, Hamilton R, et al. Systematic improvement in charge carrier mobility of air stable triarylamine copolymers. J Am Chem Soc, 2009, 131: 10814–10815

    Article  CAS  Google Scholar 

  28. Peng C, Liu H, Han X, et al. Construction of a fully conjugated cross-linked hole-transport film based on ethynyl to enable high mobility for efficient solution-processed OLEDs. J Mater Chem C, 2022, 10: 14471–14479

    Article  CAS  Google Scholar 

  29. Sun W, Deng Y, Jin Y, et al. Solvent resistant hole-transporting thin films via diacetylene cross-linking and their applications in solution-processed QLEDs. ACS Appl Polym Mater, 2020, 2: 3274–3281

    Article  CAS  Google Scholar 

  30. Fujita N, Sakamoto Y, Shirakawa M, et al. Polydiacetylene nanofibers created in low-molecular-weight gels by post modification: Control of blue and red phases by the odd-even effect in alkyl chains. J Am Chem Soc, 2007, 129: 4134–4135

    Article  CAS  Google Scholar 

  31. Jordan RS, Wang Y, McCurdy RD, et al. Synthesis of graphene nanoribbons via the topochemical polymerization and subsequent aromatization of a diacetylene precursor. Chem, 2016, 1: 78–90

    Article  CAS  Google Scholar 

  32. Qian X, Städler B. Recent developments in polydiacetylene-based sensors. Chem Mater, 2019, 31: 1196–1222

    Article  CAS  Google Scholar 

  33. Sutapin C, Mantaranon N, Chirachanchai S. Eight-armed polydiacetylene under benzoxazine dimer branched polylactide: A structural combination for reversible thermochromic effects and a model case for free-standing poly(lactic acid) films. J Mater Chem C, 2017, 5: 8288–8294

    Article  CAS  Google Scholar 

  34. Yang M, Xie L, Yi YQQ, et al. Solution-processable small-molecule hole transport material for high-performance QLED via manipulating dipole moments. Adv Mater Technol, 2023, 8: 2202105

    Article  CAS  Google Scholar 

  35. Hu G, He J, Li Y. Controllable synthesis of two-dimensional graphdiyne films catalyzed by a copper(II) trichloro complex. ACS Catal, 2022, 12: 6712–6721

    Article  CAS  Google Scholar 

  36. Murgatroyd PN. Theory of space-charge-limited current enhanced by Frenkel effect. J Phys D-Appl Phys, 1970, 3: 151–156

    Article  Google Scholar 

  37. Taylor DM. Space charges and traps in polymer electronics. IEEE Trans Dielect Electr Insul, 2006, 13: 1063–1073

    Article  CAS  Google Scholar 

  38. Macdonald TJ, Clancy AJ, Xu W, et al. Phosphorene nanoribbon-augmented optoelectronics for enhanced hole extraction. J Am Chem Soc, 2021, 143: 21549–21559

    Article  CAS  Google Scholar 

  39. Cheng C, Liu A, Ba G, et al. High-efficiency quantum-dot light-emitting diodes enabled by boosting the hole injection. J Mater Chem C, 2022, 10: 15200–15206

    Article  CAS  Google Scholar 

  40. Liu A, Cheng C, Tian J. Exploring performance degradation of quantum-dot light-emitting diodes. J Mater Chem C, 2022, 10: 8642–8649

    Article  CAS  Google Scholar 

  41. Bube RH. Trap density determination by space-charge-limited currents. J Appl Phys, 1962, 33: 1733–1737

    Article  CAS  Google Scholar 

  42. Shen H, Gao Q, Zhang Y, et al. Visible quantum dot light-emitting diodes with simultaneous high brightness and efficiency. Nat Photon, 2019, 13: 192–197

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was financially supported by the National Key Research and Development Program of China (2022YFB3606500) and the Natural Science Foundation of Jiangsu Province (BK20210125). The authors are grateful for the technical support for the Nano-X from Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (SINANO).

Author information

Author notes

  1. These authors contributed equally to this work.

Authors and Affiliations

  1. Printable Electronics Research Center, Nano Devices and Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China

    Gengrui Qiu  (邱庚锐), Yuan-Qiu-Qiang Yi  (易袁秋强), Liming Xie  (谢黎明), Fuyan Su  (苏富燕), Ting Wang  (王婷), Wenming Su  (苏文明) & Zheng Cui  (崔铮)

  2. Nano Science & Technology Institute, University of Science and Technology of China, Suzhou, 215123, China

    Gengrui Qiu  (邱庚锐) & Wenming Su  (苏文明)

  3. pi-Conjugated Polymers Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan

    Yuan-Qiu-Qiang Yi  (易袁秋强)

Authors
  1. Gengrui Qiu  (邱庚锐)
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Yuan-Qiu-Qiang Yi  (易袁秋强)
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Liming Xie  (谢黎明)
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Fuyan Su  (苏富燕)
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Ting Wang  (王婷)
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Wenming Su  (苏文明)
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Zheng Cui  (崔铮)
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

Author contributions Qiu G designed and conducted the experiments and wrote the original draft; Xie L conducted some preliminary experiments; Su F and Wang T provided the ZnMgO nanocrystals; Yi YQQ designed the materials, supervised the project, and reviewed and edited the draft; Su W and Cui Z revised the manuscript. All authors contributed to the general discussion.

Corresponding authors

Correspondence to Yuan-Qiu-Qiang Yi  (易袁秋强) or Wenming Su  (苏文明).

Ethics declarations

Conflict of interest The authors declare that they have no conflict of interest.

Additional information

Gengrui Qiu is a Master’s student at the Nano Science & Technology Institute, University of Science and Technology of China. His research focuses on the inkjet-printed high-performance QLEDs based on crosslinked hole-transporting materials.

Yuan-Qiu-Qiang Yi received his PhD degree from Nankai University in 2019. Before working at Okinawa Institute of Science and Technology, he was a postdoctoral researcher at Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences. His research focuses on developing cross-linking methods and technologies for solution-processable semiconducting materials for optoelectronic devices.

Wenming Su received his PhD degree from Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences in 2007. Currently, he is a professor at the Printable Electronics Research Centre, Suzhou Institute of Nanotech and Nanobionics, Chinese Academy of Sciences. His main research is focused on printed & flexible electronics.

Supplementary information Experimental details and supporting data are available in the online version of the paper.

Electronic Supplementary Material

40843_2023_2692_MOESM1_ESM.pdf

High-efficiency inkjet-printed quantum-dot light-emitting diode enabled by solvent-resistant hole transport materials with high surface energy and extended conjugation

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Qiu, G., Yi, YQQ., Xie, L. et al. High-efficiency inkjet-printed quantum-dot light-emitting diode enabled by solvent-resistant hole transport materials with high surface energy and extended conjugation. Sci. China Mater. 67, 205–213 (2024). https://doi.org/10.1007/s40843-023-2692-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40843-023-2692-x

Keywords

Search

Navigation