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Research on Fe(NH2trz)3·(BF4)2 doped polyfluorene organic light-emitting devices

Xu Chong Niu Lian-Bin Qian Ya-Cui Wen Lin Xiong Yuan-Qiang Peng Hao-Nan Guan Yun-Xia

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Research on Fe(NH2trz)3·(BF4)2 doped polyfluorene organic light-emitting devices

Xu Chong, Niu Lian-Bin, Qian Ya-Cui, Wen Lin, Xiong Yuan-Qiang, Peng Hao-Nan, Guan Yun-Xia
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  • Since the breakthrough by Tang et al. in 1987, organic light-emitting devices (OLEDs) have attracted extensive attention in the industries and academic research communities. OLEDs have many promising characteristics, such as self-illumination, lower power consumption, easy fabrication and so on. It has a broad development prospect in high resolution display and other fields. For RGB color OLED display technology, blue light organic material is very important. Polyfluorene (PFO) is a kind of rigid planar biphenyl structure compound in all kinds of OLEDs blue light materials. However, PFO has a very big disadvantage: the long wave shift of the light-emitting peak of the electroluminescent device will produce the green light-emitting band that should not have appeared. This seriously affects the saturation color purity of PFO devices, and also seriously restricts the industrialization process. In this paper, the molecular magnetic material [Fe(NH2trz)3· (BF4)2] is used to solve this problem. ITO/PEDOT:PSS (30 nm)/PFO:Fe(NH2trz)3·(BF4)2 (65 nm)/CsCl (0.6 nm)/Al (120 nm) devices were fabricated on ITO glass substrate. It is the first time to report the strong pure blue emission of PFO by using the special electronic spin state modulation of Fe(NH2trz)3·(BF4)2. The influence of Fe(NH2trz)3·(BF4)2 on the photoelectric properties of PFO was studied in detail by analyzing the PL and EL characteristics of PFO and PFO:Fe(NH2trz)3·(BF4)2. Under the bias voltage of 4 V to 9 V, the device without doping Fe(NH2trz)3·(BF4)2 emits very strong green light. The central peak wavelength is 553 nm, and the color coordinates are (0.33, 0.45). Moreover, with the constant change of voltage, the green light-emitting band is always much larger than the blue light-emitting band. However, the obvious difference is that Fe(NH2trz)3·(BF4)2 doped device emits strong blue light, the peak wavelength is 438 nm, and the color coordinates (0.23, 0.22), which is completely consistent with the peak wavelength of the PL spectrum of the PFO film; the green light-emitting band of the PFO is successfully suppressed; with the change of the electric voltage, the proportion of the blue light part of the device spectrum in the whole EL spectrum is almost unchanged. The photoconductivity effect of undoped Fe(NH2trz)3·(BF4)2 device is further studied by means of the integrated opto-electro-magnetic measurement technology. Under different bias voltage, it is found that there is almost no excimer in PFO:Fe(NH2trz)3·(BF4)2. This study solves the problem of green light of polyfluorene, which has puzzled the industry for many years, and provides a reliable way for the industrialization of polyfluorene used in blue OLED. The mechanism of Fe(NH2trz)3·(BF4)2 blocking the abnormal green emission of PFO was discussed by using the theory of luminescence dynamics.
      Corresponding author: Niu Lian-Bin, niulb03@126.com ; Peng Hao-Nan, phn@snnu.edu.cn ; Guan Yun-Xia, utk_lili@126.com
    • Funds: Project supported by the National Natural Science Foundation of China (Grant Nos. 61874016, 11875010), the Natural Science Foundation Project of CQ CSTC (Grant Nos. CSTC 2020jcyj-msxmX0282, CSTC2019jcyj-msxmX0148), and the Research Programs for Science and Chongqing Science and Technology Innovation Leading Talents Support Plan (Grant No. CSTC 2018kjcxljrc0050)
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    Tang C W, VanSlyke S A V 1987 Appl. Phys. Lett. 51 913Google Scholar

    [2]

    Ghosh I, Khamrai J, Savateev A K 2019 Science 365 360Google Scholar

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    肖心明, 朱龙山, 关宇, 华杰, 王洪梅, 董贺, 汪津 2020 物理学报 69 047202Google Scholar

    Xiao X M, Zhu L S, Guan Y, Hua J, Wang H M, Dong H, Wang J 2020 Acta Phys. Sin. 69 047202Google Scholar

    [4]

    Niu L B, Chen L J, Chen P, Cui Y T, Zhang Y, Shao M, Guan Y X 2016 RSC Adv. 6 111421Google Scholar

    [5]

    Burroughes J H, Bradley D C, Brown A R, Marks R N, Mackay K, Richard H F, Burns P L 1990 Nature 347 539Google Scholar

    [6]

    Stefan B, Christophe E, Andrew C G, Emil J W, Marsitzky D, Alexander P, Sepas Setayesh, Leising G, Mullen K 2001 Synth. Met. 125 73Google Scholar

    [7]

    Marystela F, Clarissa A O, Angelita M M, Andressa M A, José A G, Leni A, Osvaldo N J 2007 J. Polym. Res. 14 39Google Scholar

    [8]

    Inaoka S, Advincula R 2002 Macromolecules 35 2426Google Scholar

    [9]

    Mark T B, Michael I, Edmund P W, Wei W W, Lisa W K 1999 Proc. SPIE, Light-Emitting Diodes: Research, Manufacturing, and Applications III, 3621 93

    [10]

    Niu L B, Chen L J, Tao S L, Guan Y X 2018 J. Mol. Liq. 259 411Google Scholar

    [11]

    Gong X, Iyer P K, Moses D, Bazan G C, Heeger A J, Xiao S 2003 Adv. Funct. Mater. 13 325Google Scholar

    [12]

    Emil J W, Guentner R, Scanducci P D, Ullrich S 2002 Adv. Mater. 14 374

    [13]

    Mathieu S, Emmanuelle H, Christophe E, Dirk M, Andrew C G, Müllen K, Brédas J L, Roberto L, Philippe L 2004 Chem. Mater. 16 994Google Scholar

    [14]

    姜鸿基, 万俊华, 黄维 2008 中国科学: 化学 38 183

    Jiang H J, Wan J H, Huang W 2016 Science in China: Chemistry 46 037001 (in Chinese)

    [15]

    Malcolm A H, Izar C B, Christopher M P, Kulmaczewski R 2019 Inorg. Chem. 58 9811Google Scholar

    [16]

    Sun H Y, Meng Y S, Liu T 2019 Chem. Commun. 55 8359Google Scholar

    [17]

    Wang C F, Li R F, Chen X Y, Wei R J, Zheng L S, Tao J 2015 Angew. Chem. 54 1574Google Scholar

    [18]

    Kitts C C, Vanden B D 2007 Polymer 48 2322Google Scholar

    [19]

    Bradley D D C, Grell M, Lo ng, X, Mellor H, Grice A 1998 Proc. SPIE 3145 254

    [20]

    Klarner G, Davey M. H, Chen W D, Scott J C, Miller 1998 R D Adv. Mater. 10 993Google Scholar

    [21]

    List J W, Guentner R, Freitas P S, Scherf U 2002 Advanced Materials 14 374

    [22]

    Gaal M, List E J W, Scherf U 2003 Macromolecules 36 4236Google Scholar

    [23]

    Gamerith S, Gaal M, Romaner L, Nothofer H G, Guntner R, Freitas P S, Scherf U, List E J W 2003 Synth. Met. 139 855Google Scholar

    [24]

    Kappaun S, Scheiber H, Trattnig R, Zojer E, List E J W, Slugovc C 2008 Chem. Commun. 51 70

    [25]

    Gong X, Iyer P K, Moses D, Bazan G C, Heeger A J, Xiao S S 2003 Advanced Funct. Materials 13 325

    [26]

    Lapres A, Silvia T, Manuel H, Alfonso S 2013 Chem. Commun. 49 288Google Scholar

    [27]

    白凤莲 1985 化学通报 6 31

    Bai F L 1985 Chemistry Bulletin 6 31

    [28]

    Förster T, Kasper K 1954 Phys. Chem. N. F. 1 275Google Scholar

    [29]

    Yuan P S, Qiao X F, Yan D H, Ma D G 2019 J. Mater. Chem. C 7 1035Google Scholar

    [30]

    Xiang J, Chen Y B, Yuan D, Jia W Y, Zhang Q M, Xiong Z H 2016 Appl. Phys. Lett. 109 103301Google Scholar

    [31]

    赵茜, 汤仙童, 潘睿亨, 许静, 屈芬兰, 熊祖洪 2019 科学通报 64 2514Google Scholar

    Zhao X, Tang X T, Pan R H, Qu F L, Xiong Z H 2019 Chin. Sci. Bull 64 2514Google Scholar

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    Xiang J, Chen Y B, Jia W Y, Chen L X, Lei Y L, Zhang Q M, Xiong Z H 2016 Org. Electron. 28 94Google Scholar

    [33]

    Zhao B, Zhang H, Miao Y Q, Wang Z Q, Gao L, Wang H, Hao Y Y, Xu B S, Li W L 2017 J. Mater. Chem. C 5 12182Google Scholar

    [34]

    Jiang F, Dong M Q, Wang Y N 2020 J. Magn. Magn. Mater. 497 165969Google Scholar

    [35]

    刘俊娟, 魏增江, 常虹, 张亚琳, 邸冰 2016 物理学报 65 067202Google Scholar

    Liu J J, Wei Z J, Chang H, Zhang Y L, Di B 2016 Acta Phys. Sin. 65 067202Google Scholar

  • 图 1  (a)器件结构; (b)磁效应测试原理示意图

    Figure 1.  Schematic description of the device structure (a) and the device fabricated for the MEL measurements (b).

    图 2  Fe(NH2trz)3·(BF4)2合成路线和材料分子结构示意图

    Figure 2.  Schematic description of synthetic route and molecular structures of the materials studied.

    图 3  不同电压下, 器件ITO/PEDOT: PSS/PFO/CsCl/Al的归一化电致发光EL谱

    Figure 3.  Normalized EL spectra of the device with ITO/PEDOT: PSS/PFO/CsCl/Al.

    图 4  PFO薄膜的PL谱(红色)和8 V偏置电压的 EL谱(黑色)

    Figure 4.  PL(red)and EL(black)spectra of the PFO film at 8 V.

    图 5  (a)器件ITO/PEDOT: PSS/PFO: Fe(NH2trz)3·(BF4)2/CsCl/Al的电致发光EL谱; (b)该器件的电流-电压-亮度曲线

    Figure 5.  (a) EL spectra of the device with ITO/PEDOT: PSS/PFO: Fe(NH2trz)3·(BF4)/CsCl/Al; (b) I-V-L characteristics response of the device

    图 6  PFO: Fe(NH2trz)3·(BF4)2薄膜的PL谱(紫色)和7 V偏置电压的 EL谱(青色)

    Figure 6.  PL(purple)and EL(ching)spectra of the PFO: Fe(NH2trz)3·(BF4)2 film at 7 V.

    图 7  不同电压下器件ITO/PEDOT: PSS/PFO: Fe(NH2trz)3·(BF4)2/CsCl/Al的磁发光曲线(a)和MC曲线(b)

    Figure 7.  MEL (a) and MC (b) of the device with ITO/PEDOT: PSS/ PFO: Fe(NH2trz)3·(BF4)2/CsCl/Al under different voltage

    图 8  不同电压下器件ITO/PEDOT: PSS/ PFO/CsCl/Al的磁发光曲线 (a)和MC曲线(b)

    Figure 8.  MEL (a) and MC (b) of the device with ITO/PEDOT: PSS/ PFO/CsCl/Al under different voltage.

    图 9  Fe(NH2trz)3·(BF4)2耦合“剪断”PFO在电致发光过程中被氧化为芴酮机理图

    Figure 9.  Mechanism diagram of Fe(NH2trz)3·(BF4)2 coupling cutting PFO oxidation to fluorenone in electroluminescence.

  • [1]

    Tang C W, VanSlyke S A V 1987 Appl. Phys. Lett. 51 913Google Scholar

    [2]

    Ghosh I, Khamrai J, Savateev A K 2019 Science 365 360Google Scholar

    [3]

    肖心明, 朱龙山, 关宇, 华杰, 王洪梅, 董贺, 汪津 2020 物理学报 69 047202Google Scholar

    Xiao X M, Zhu L S, Guan Y, Hua J, Wang H M, Dong H, Wang J 2020 Acta Phys. Sin. 69 047202Google Scholar

    [4]

    Niu L B, Chen L J, Chen P, Cui Y T, Zhang Y, Shao M, Guan Y X 2016 RSC Adv. 6 111421Google Scholar

    [5]

    Burroughes J H, Bradley D C, Brown A R, Marks R N, Mackay K, Richard H F, Burns P L 1990 Nature 347 539Google Scholar

    [6]

    Stefan B, Christophe E, Andrew C G, Emil J W, Marsitzky D, Alexander P, Sepas Setayesh, Leising G, Mullen K 2001 Synth. Met. 125 73Google Scholar

    [7]

    Marystela F, Clarissa A O, Angelita M M, Andressa M A, José A G, Leni A, Osvaldo N J 2007 J. Polym. Res. 14 39Google Scholar

    [8]

    Inaoka S, Advincula R 2002 Macromolecules 35 2426Google Scholar

    [9]

    Mark T B, Michael I, Edmund P W, Wei W W, Lisa W K 1999 Proc. SPIE, Light-Emitting Diodes: Research, Manufacturing, and Applications III, 3621 93

    [10]

    Niu L B, Chen L J, Tao S L, Guan Y X 2018 J. Mol. Liq. 259 411Google Scholar

    [11]

    Gong X, Iyer P K, Moses D, Bazan G C, Heeger A J, Xiao S 2003 Adv. Funct. Mater. 13 325Google Scholar

    [12]

    Emil J W, Guentner R, Scanducci P D, Ullrich S 2002 Adv. Mater. 14 374

    [13]

    Mathieu S, Emmanuelle H, Christophe E, Dirk M, Andrew C G, Müllen K, Brédas J L, Roberto L, Philippe L 2004 Chem. Mater. 16 994Google Scholar

    [14]

    姜鸿基, 万俊华, 黄维 2008 中国科学: 化学 38 183

    Jiang H J, Wan J H, Huang W 2016 Science in China: Chemistry 46 037001 (in Chinese)

    [15]

    Malcolm A H, Izar C B, Christopher M P, Kulmaczewski R 2019 Inorg. Chem. 58 9811Google Scholar

    [16]

    Sun H Y, Meng Y S, Liu T 2019 Chem. Commun. 55 8359Google Scholar

    [17]

    Wang C F, Li R F, Chen X Y, Wei R J, Zheng L S, Tao J 2015 Angew. Chem. 54 1574Google Scholar

    [18]

    Kitts C C, Vanden B D 2007 Polymer 48 2322Google Scholar

    [19]

    Bradley D D C, Grell M, Lo ng, X, Mellor H, Grice A 1998 Proc. SPIE 3145 254

    [20]

    Klarner G, Davey M. H, Chen W D, Scott J C, Miller 1998 R D Adv. Mater. 10 993Google Scholar

    [21]

    List J W, Guentner R, Freitas P S, Scherf U 2002 Advanced Materials 14 374

    [22]

    Gaal M, List E J W, Scherf U 2003 Macromolecules 36 4236Google Scholar

    [23]

    Gamerith S, Gaal M, Romaner L, Nothofer H G, Guntner R, Freitas P S, Scherf U, List E J W 2003 Synth. Met. 139 855Google Scholar

    [24]

    Kappaun S, Scheiber H, Trattnig R, Zojer E, List E J W, Slugovc C 2008 Chem. Commun. 51 70

    [25]

    Gong X, Iyer P K, Moses D, Bazan G C, Heeger A J, Xiao S S 2003 Advanced Funct. Materials 13 325

    [26]

    Lapres A, Silvia T, Manuel H, Alfonso S 2013 Chem. Commun. 49 288Google Scholar

    [27]

    白凤莲 1985 化学通报 6 31

    Bai F L 1985 Chemistry Bulletin 6 31

    [28]

    Förster T, Kasper K 1954 Phys. Chem. N. F. 1 275Google Scholar

    [29]

    Yuan P S, Qiao X F, Yan D H, Ma D G 2019 J. Mater. Chem. C 7 1035Google Scholar

    [30]

    Xiang J, Chen Y B, Yuan D, Jia W Y, Zhang Q M, Xiong Z H 2016 Appl. Phys. Lett. 109 103301Google Scholar

    [31]

    赵茜, 汤仙童, 潘睿亨, 许静, 屈芬兰, 熊祖洪 2019 科学通报 64 2514Google Scholar

    Zhao X, Tang X T, Pan R H, Qu F L, Xiong Z H 2019 Chin. Sci. Bull 64 2514Google Scholar

    [32]

    Xiang J, Chen Y B, Jia W Y, Chen L X, Lei Y L, Zhang Q M, Xiong Z H 2016 Org. Electron. 28 94Google Scholar

    [33]

    Zhao B, Zhang H, Miao Y Q, Wang Z Q, Gao L, Wang H, Hao Y Y, Xu B S, Li W L 2017 J. Mater. Chem. C 5 12182Google Scholar

    [34]

    Jiang F, Dong M Q, Wang Y N 2020 J. Magn. Magn. Mater. 497 165969Google Scholar

    [35]

    刘俊娟, 魏增江, 常虹, 张亚琳, 邸冰 2016 物理学报 65 067202Google Scholar

    Liu J J, Wei Z J, Chang H, Zhang Y L, Di B 2016 Acta Phys. Sin. 65 067202Google Scholar

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Publishing process
  • Received Date:  31 August 2020
  • Accepted Date:  30 November 2020
  • Available Online:  29 March 2021
  • Published Online:  05 April 2021

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