OPTICAL MATERIALS
·
2022
·
IF 3.754
Wentong Gao,Wenlu Wu,Shihai Cao,Bing Han,Nengquan Li
Solution-processable host materials play an important role in achieving highly efficient and cost-effective phosphorescent organic light-emitting diodes (PhOLEDs). This paper designed and prepared a simple solution-processable host material of TPA-PyF 2 based on triphenylamine and pyridine to fabricate efficient solution-processed PhOLEDs. TPA-PyF 2 featured an σ-linkage between the electron donor and acceptor units, which not only served to limit the conjugation length of the molecule and maintain a high triplet energy level, but also endowed the host molecule with a three-dimensional structure to enable high film morphological stability for solution processing. As a result, TPA-PyF 2 exhibited a high triplet energy level (2.82 eV), high thermal stability, bipolar charge transfer, and excellent film morphology. Blue solution-processed OLED with a simple double-layer structure based on TPA-PyF 2 host achieved a maximum current efficiency, power efficiency, and luminance of 17.2 cd/A, 7.1 lm/W, and 11519 cd/m 2 , respectively, with a small efficiency roll-off of only 9.1% at the practical luminance of 1000 cd/m 2 . This work reveals that the σ-linkage strategy is promising in designing efficient solution-processable host materials for high-efficiency PhOLEDs.
研究领域:
材料科学
·
有机电子学
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产品关联
DOI
高影响因子
Applied Nanoscience
·
2019
·Vol. 9
·期 8
·1971-1979
·
IF 3.198
Gu Ze-Zeng,Tian Ying,Geng Hong-Zhang,Rhen Danielle S.,Ethiraj Anita Sagadevan,Zhang Xingcai,Jing Li-Chao,Wang Tao,Xu Zi-Han,Yuan Xiao-Tong
Carbon nanotubes (CNTs) and poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) were employed to prepare sandwich-structured CNT/PEDOT:PSS/CNT transparent conductive films (TCFs) on flexible polyethylene terephthalate (PET) substrate by a spraying method. Based on the film morphology, we suggest that the CNTs were embedded in PEDOT:PSS. The structured film was more stable and did not peel off during post-processing nitric acid treatment. Ethylene glycol (EG) was used to improve the conductivity of the film, and the best ratio of PEDOT:PSS to EG was 10:5. XPS and Raman spectroscopy studies revealed that the non-conductive sodium dodecylbenzene sulfonate and PSS were removed during the nitric acid treatment. TCF sheet resistance as low as 95.15 Ω/sq at 87.72% transmittance (at a wavelength of 550 nm) was obtained. When the CNT/PEDOT:PSS/CNT-TCF was used as an anode in an organic light emitting diode, the high luminance of the device was 1598 cd/cm 2 at 14 V, and the maximum current efficiency was 1.5 cd/A at 13 V.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 40
·15000-15007
·
IF 8.067
Han Zhang,Wenqing Zhu,Lu Huang,Chen Yi,Ruilin Chen,Yipeng Chen,Jun Li
The hole-injection layer (HIL) plays a critical role in the efficiency and stability of organic light-emitting diodes (OLEDs). However, inorganic HIL materials, such as transition metal oxides (TMOs), usually suffer the problems of low conductivity and mismatched work function at ITO/hole-transport layer (HTL) interfaces, which limits the hole-injection in OLEDs. In this paper, a gold (Au) and lithium (Li) co-doping strategy has been employed to fabricate a vanadium oxide (VOx) HIL through solution processing at low temperature for improving device performance. Compared to non-doped VOx and Au-doped VOx films, co-doping with an optimal molar ratio of Au and Li endows the VOx films with both higher electrical conductivity and proper work function matching with the ITO anode and HTL, which leads to efficient hole-injection and improved carrier balance in the device with the Au and Li co-doped VOx (Au,Li:VOx) HIL. As a result, the device with the Au,Li:VOx HIL shows a peak power efficiency of 50.2 lm W−1 and a maximum external quantum efficiency (EQE) of 19.9%, which are superior to those of the counterpart with the VOx HIL (34.4 lm W−1 and 18.1%). Meanwhile, the device shows distinguished stability. This work indicates that Au and Li co-doping is an effective method to obtain an efficient VOx HIL with excellent hole-injection ability, which provides a promising avenue to enhance OLED performance.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2015
·Vol. 26
·期 9
·6563-6571
·
IF 1.569
Lu Tianxing,You Jing,Zhao Dan,Wang Hua,Miao Yanqin,Liu Xicheng,Xiao Yin,Li Xianggao,Wang Shirong
Three s -triazine/carbazole based bipolar molecules: 9,9′,9″-(1,3,5-triazine-2,4,6-triyl)tris(3,6-di- tert -butyl-carbazole) (TazTCz), 9,9′-(6-phenyl-1,3,5-triazine-2,4-diyl)bis(3,6-di- tert -butyl-carbazole) (PhTazDCz) and 9-(4,6-diphenyl-1,3,5-triazine-2-yl)-3,6-di- tert -butyl-carbazole (DPhTazCz) were synthesized and applied as host materials for blue phosphorescent organic light-emitting diodes (PHOLEDs). The triplet state energy levels are ~2.86 eV for these compounds, ensured their application in blue PHOLEDs. X-ray single crystal structural analysis revealed a non-planar structure of TazTCz, which prevented the intermolecular close-packing in the solid state. X-ray diffraction spectra also confirmed that TazTCz and PhTazDCz could form amorphous films with spin-coating method. The bipolar characteristics of as-synthesized compounds were confirmed by carrier mobility measurement. The device parameters of blue PHOLEDs based on these compounds as host materials exhibit that the balance of electron and hole mobilities is benefit for reducing turn-on voltage and efficiency roll-off at high current density.
研究领域:
材料科学
·
有机电子学
✓ 已验证
产品关联
DOI
高影响因子
THIN SOLID FILMS
·
2023
·
IF 2.1
Liang Zhao,Xiaozhe Cheng,Weizhen Xia,Lingling Yao,Zhitao Dou,Haibin Xue,Hong Lian,Yongquan Qu,Qingchen Dong
In this work, we designed and synthesized two bipolar host materials, DBTPC1 and DBTPC2 through different linkage ways between carbazole, pyridine and dibenzothiophene. The photophysical properties and thermal properties of these hosts were systematically investigated. Their rigid molecular structures result in high glass transition temperatures , contributing to excellent thermal stability of molecules. Employing DBTPC1 and DBTPC2 as hosts, red phosphorescent organic light-emitting devices (PHOLEDs) with Ir(piq) 2 acac as an emitter display maximum external quantum efficiencies (EQEs) of 18.8 and 13.2%, respectively. The experimental results reveal that DBTPC1 shows better performance than commercial host 4,4’-bis(carbazol-9-yl)biphenyl (CBP), thus, would be a promising host material for practical application in red PHOLEDs and for the future exploration in multi-color PHOLEDs.
研究领域:
材料科学
·
光电化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Chenxi Liu,Mengze Li,Yifan Wang,Zijie Hou,Jian Chen,Kun Cao,Lihui Liu,Shufen Chen
The development of flexible organic light-emitting didoes (FOLEDs) has spurred the research on flexible transparent electrodes (FTEs). Poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) is one of the most attractive FTEs due to its adjustable conductivity and compatibility with low-cost and large-scale solution processing techniques. Significantly, highly efficient FOLEDs have been achieved with modified PEDOT:PSS FTEs. However, the intrinsic mechanisms that contribute to device degradation of FOLEDs utilizing PEDOT:PSS FTEs have not yet been fully elucidated. In this work, three ionic liquids (ILs) are used to enhance the electrical conductivity and mechanical flexibility of PEDOT:PSS FTEs. Simultaneously, the influence of the electric field induced ion migration from PEDOT:PSS FTEs on the operational stability of FOLEDs is unraveled. We find that the ILs with larger ionic radii and higher steric hindrance are beneficial to suppressing the electrical field induced ion migration and improving the operational stability of FOLEDs. Finally, large-area and high-performance FOLEDs are achieved based on the IL of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide modified PEDOT:PSS FTEs, which demonstrate a high current efficiency of 98.1 cd/A and a longer lifetime of 66.7 min. This finding may promote the practical application of PEDOT:PSS FTEs in flexible optoelectronics.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ORGANIC ELECTRONICS
·
2016
·
IF 3.471
Jie Zhang,Xunjin Zhu,Aiguo Zhong,Wenping Jia,Fengshou Wu,Dan Li,Hongbo Tong,Chenglin Wu,Wenyuan Tang,Ping Zhang,Lei Wang,Deman Han
The condensation of different groups substituted salicylaldehydes with aniline and 2,4,5-trifluoroaniline, afforded five one-armed Schiff base ligands HL 1 , HL 2 , HL 3 , HL 4 and HL 5 . And their platinum(II) complexes Pt(L 1 ) 2 , Pt(L 2 ) 2 , Pt(L 3 ) 2 , Pt(L 4 ) 2 , Pt(L 5 ) 2 and PtL 5 · DMSO were prepared through the metallation of ligands with K 2 PtCl 4 . All ligands and complexes were characterized by 1 H NMR, infrared spectroscopy , mass spectrometry and single crystal X-ray diffraction. And their thermal stability, photophysical properties, and electrochemical behaviors were investigated in detail. Using these complexes as phosphorescent emitting materials, blue to orange light-emitting devices were fabricated with moderate efficiencies. The maximum current efficiency, power efficiency, and brightness for the 3.0 wt % Pt(L 3 ) 2 doped OLED are 1.12 cd A −1 , 0.62 l m W −1 and 1521 cd m −2 , respectively. Given the synthetic simplicity and ease of structural variation, the results here indicate that these platinum(II) Schiff base complexes are good candidates for phosphorescent OLEDs.
研究领域:
材料化学
·
发光材料
·
有机电子学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Jingxiang Wang,Hongli Liu,Sen Wu,Yi Jia,Hang Yu,Xianggao Li,Shirong Wang
Recently, developing insoluble cross-linkable functional layers plays a vital role for solution-processed organic light emitting diodes (OLEDs). Here, two vinyl-based cross-linkable hole transporting materials V-TPAVTPD and V-TPAVCBP are designed and synthesized. Additionally, cationic photoinitiator 4-octyloxydiphenyliodonium hexafluoroantimonate (OPPI) is first introduced to chemically induce vinyl-based photo cross-linking process, aiming at lowering cross-linking temperature and enhancing hole mobility. As a result, cross-linking can occur at expressly low temperature of 120 °C with >95% solvent resistance. Moreover, hole mobility is markedly enhanced with the value higher than 10 −3 cm 2 V −1 s −1 . When applying hole transporting layers (HTLs) to solution-processed green and red phosphorescent OLEDs, devices exhibit excellent properties. Particularly, the maximum current efficiency of 54.0 cd A −1 (green), 9.8 cd A −1 (red) and external quantum efficiency of 15.5% (green), 15.0% (red) are obtained when OPPI doped V-TPAVCBP serves as HTL. This low temperature feasible cross-linking process to prepare HTLs with preferable hole mobility promotes the development of OLEDs.
研究领域:
材料科学
·
光电技术
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2026
·Vol. 8
·期 14
·11442-11450
·
IF 5.2
Xia Dacheng,Zhang Qiuyi,Shen Shuwen,Sheng Chenxu,Liu Hong,Xie Fengxian,Cong Chunxiao,Qiu Zhi-Jun,Hu Laigui,Liu Ran
The
rapid advancement of near-eye display technologies
has generated
strong demand for high-resolution microdisplays. Organic light-emitting
diodes (OLEDs), with their mature industrialization, lightweight nature,
and compatibility with flexible substrates, represent an ideal platform
for head-mounted high-resolution microdisplays. However, achieving
high-resolution and precise patterning of organic light-emitting materials
remains a significant challenge. Conventional patterning methods often
destroy organic materials and are incapable of high-resolution patterning.
Photochemical cross-linking provides a promising route for direct
patterning of polymer semiconductors, while the application in the
fabrication of micro-OLEDs has been rarely explored. To address the
gaps in the existing research studies, a semiconducting photoresist
was developed, and its effects on device performance were investigated
in this work. The photoresist was obtained by blending the light-emitting
polymer poly[2-methoxy-5-(2 ′ -ethylhexyloxy)-1,4-phenylenevinylene]
(MEH-PPV) with commercially available, low-cost cross-linking agents.
An insoluble polymer network was thus formed through a UV-initiated
thiol–ene addition reaction. High-resolution patterning of
2.6 μm dots and 5 μm lines is then achieved by using conventional
photolithography methods. Ultimately, high-resolution micro-OLED arrays
with a 5 μm pixel size and 3175 pixels per inch (PPI) were successfully
demonstrated. This work provides a versatile and scalable approach
for direct patterning of emissive layers (EMLs) in OLED devices.
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DOI
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Peng-Fei Qian,Wen-Hao Geng,Ze-Long Bao,Li-Chao Jing,Di Zhang,Hong-Zhang Geng
In this study, gentianic acid (GtA) was first doped into poly (3,4-ethylenedioxythiophene): poly (styrene-sulfonic) (PEDOT:PSS), and the doped PEDOT:PSS (GP) was spin-coated as a hydrophilic layer on the surface of relatively hydrophobic polyethylene terephthalate (PET) films. After that, silver nanowires (AgNWs) aqueous dispersion and hydroxypropyl methyl cellulose (HPMC) solution were coated over the surface of PET films. Finally, the GP/AgNWs/HPMC flexible conductive films were stripped from the PET surface, achieving a high visible light transmittance (81.5 % at 550 nm) with low sheet resistance (4.2 Ω/□). By embedding AgNWs on the surface of the HPMC film, the surface roughness ( R q) of this flexible transparent conductive film (TCF) was as low as 3.2 nm, meeting the requirements for the fabrication of organic light-emitting diode (OLED) devices. The OLED device fabricated via using this TCF as the anode achieved a maximum brightness ( L max ) of 13,740 cd/m 2 , a maximum current efficiency ( C.E. max ) of 10.6 cd/A, a maximum power efficiency ( P.E. max ) of 5.5 lm/W and a maximum external quantum efficiency ( EQE max ) of 2.9 %. Furthermore, HPMC demonstrated solubility in water at ambient temperature, facilitating the recycling of AgNWS and mitigating environmental pollution. These findings provide a new scope for the application of TCF in recyclable flexible electronic devices.
研究领域:
材料科学
·
电子工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Shi-Wei Wang,Peng-Fei Qian,Di Zhang,Wen-Hao Geng,Yi-Song Zhang,Xuan-Chen Liu,Lu-Yao Tian,Qingxia Zhu,Hong-Zhang Geng
In this work, the large-area poly 3,4-ethylenedioxythiophene (PEDOT: PSS) transparent conductive films (TCFs) were prepared by the solution shear method. These films exhibited excellent bendability , strong adhesion , superior uniformity, and high-light transmission. The optimum photoelectric figure of merit (FoM) of the films was 195.5, and the optimum photoelectric performance at a low sheet resistance (< 50 Ω/sq) was observed in the three-layer films, which was prepared at a dilution ratio of 2:1 and a shear rate of 1 mm/s, showing a thin-layer resistance of 34.7 Ω/sq, a transmittance of 93.2 %, an FoM of 151.9 and electrical conductivity of 2398.6 S/cm. The prepared films were used as the organic light-emitting diode (OLED) anode, and the large-area flexible green OLED device with good uniformity was obtained. The maximum current efficiency of the prepared large-area flexible OLED was 2.16 cd/A, reflecting the great potential of this solution-shear film in the field of flexible devices.
研究领域:
材料科学
·
光电技术
·
柔性电子
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2021
·
IF 4.598
Zhenghui Yang,Pingchuan Ma,Furong Li,Haiquan Guo,Chuanqing Kang,Lianxun Gao
The flexibility of organic light-emitting diode (OLED) displays highly depends on the properties of the flexible substrates. In this paper, a series of aromatic polyimides have been fabricated via the copolycondensation of pyromellitic dianhydride (PMDA), the two different rigid heterocyclic diamines, 2,5-bis(4-aminophenyl)pyrimidine (PRM) or 2,5-bis(4-aminophenyl)pyridine (PRD), and another flexible diamine, 4,4′-oxydianiline (ODA). The performance of the polyimide films could be systematically tailored by means of adjusting the main-chain rigidity, as well as the close packing and orientation of polymer chains by the formation of the intermolecular hydrogen bonds between poly(amic acid)s. The optimal results (PIb-4, PIb-5, PIc-2) showed that the polyimides were endowed with ultra-high glass transition temperature (T g ) exceeding 450 °C, low coefficient of thermal expansion (CTE) at 0–5 ppm K −1 and excellent thermal stability (T d5% = 570–590 °C). Meanwhile, all of them exhibited sufficient flexibility, the elongation at break at of 40–60%, extremely high tensile strength of 250–380 MPa and modulus of 4.1–6.1 GPa. Hence, the polyimide films should be the promising candidates for application as the polymer substrates for flexible OLED displays.
研究领域:
材料科学
·
显示技术
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DOI
高影响因子
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