Abnormal temperature dependent behaviors of intersystem crossing from rubrene guest dopant with Alq<sub>3</sub> and CBP hosts

logo

Journals Books
Advanced Search
Sign in Register

中文

SCIENTIA SINICA Physica, Mechanica & Astronomica
Download PDF
SCIENTIA SINICA Physica, Mechanica & Astronomica, Volume 48, Issue 11: 117001(2018) https://doi.org/10.1360/SSPMA2018-00088

Abnormal temperature dependent behaviors of intersystem crossing from rubrene guest dopant with Alq3 and CBP hosts

XianTong TANG, Jing XU, JinQiu DENG, RuiHeng PAN, YeQian HU, ZuHong XIONG, XiaoLi CHEN*
More info
  • ReceivedMar 29, 2018
  • AcceptedApr 23, 2018
  • PublishedAug 3, 2018
PACS numbers
Previous Table of Contents Next
Share
Rating

Abstract

In order to study the microscopic process in rubrene-doped organic light emitting diodes, two kinds of devices were fabricated by utilizing the host materials of 4,4’-N,N’-dicarbazolebiphenyl (CBP) and tris-8-hydroxyquinoline aluminum (Alq3), as well as the fluorescent dopant material 5,6,11,12-tetraphenylnaphthacene (rubrene). The magneto-electroluminescence (MEL) curves were measured in the temperature range of 20?K to 300?K. It was found that the MEL curves of rubrene dopant with Alq3 and CBP devices were composed of two parts, namely, the low field effect dominated by the intersystem crossing (ISC) process and the high field effect dominated by the triplet-triplet annihilation (TTA) process. Compared with the conventional un-doped device, the low field effects of these three devices exhibit the same change trend at the same temperature. At different temperatures, these devices show diametrically opposite changes. Specifically, the low field effect in un-doped device shows that the ISC process weakens with the decrease of the temperature, but the low field effects of rubrene dopant with Alq3 and CBP devices show that the ISC process increases with decreasing temperature. By analyzing the energy level structure of the device, the emission spectra of host materials and absorption spectra of guest material, it demonstrated that both the carrier trap effect and the F?rster energy transfer process were included in the microscopic processes of rubrene dopant with Alq3 and CBP devices. The carrier trap effect mainly affects the high field effect of MEL and is basically independent of temperature changes. This anomalous temperature-dependent behavior of ISC process can be ascribed to the suppression of F?rster energy transfer process at low temperatures, leading to an increase in the number of polaron pairs in the host material. Therefore, the ISC interaction between the polaron pairs will increase with decreasing temperature. Our work has a certain role in promoting the understanding for the evolution of microscopic mechanisms in rubrene doped devices.


Funded by

国家自然科学基金(11374242)


References

[1] Podzorov V, Menard E, Borissov A, et al. Intrinsic charge transport on the surface of organic semiconductors. Phys Rev Lett, 2004, 93: 086602 CrossRef PubMed ADS Google Scholar

[2] Najafov H, Lee B, Zhou Q, et al. Observation of long-range exciton diffusion in highly ordered organic semiconductors. Nat Mater, 2010, 9: 938-943 CrossRef PubMed ADS Google Scholar

[3] Ma L, Zhang K, Kloc C, et al. Singlet fission in rubrene single crystal: Direct observation by femtosecond pump-probe spectroscopy. Phys Chem Chem Phys, 2012, 14: 8307-8312 CrossRef PubMed ADS Google Scholar

[4] Briseno A, Tseng R, Ling M M, et al. High-performance organic single-crystal transistors on flexible substrates. Adv Mater, 2006, 18: 2320-2324 CrossRef Google Scholar

[5] Piland G B, Burdett J J, Kurunthu D, et al. Magnetic field effects on singlet fission and fluorescence decay dynamics in amorphous rubrene. J Phys Chem C, 2013, 117: 1224-1236 CrossRef Google Scholar

[6] Tarasov V V, Zoriniants G E, Shushin A I, et al. The role of spin-lattice relaxation in magnetic field effects on the luminescence of amorphous and polycrystalline rubrene films. Chem Phys Lett, 1997, 267: 58-64 CrossRef ADS Google Scholar

[7] Kalinowski J, Cocchi M, Virgili D, et al. Magnetic field effects on emission and current in Alq3-based electroluminescent diodes. Chem Phys Lett, 2003, 380: 710-715 CrossRef ADS Google Scholar

[8] Bai J W, Chen P, Lei Y L, et al. Studying singlet fission and triplet fusion by magneto-electroluminescence method in singlet-triplet energy-resonant organic light-emitting diodes. Org Electron, 2014, 15: 169-174 CrossRef Google Scholar

[9] Liu R, Zhang Y, Lei Y L, et al. Magnetic field dependent triplet-triplet annihilation in Alq3-based organic light emitting diodes at different temperatures. J Appl Phys, 2009, 105: 093719 CrossRef ADS Google Scholar

[10] Chen Q, Jia W, Chen L, et al. Determining the origin of half-bandgap-voltage electroluminescence in bifunctional rubrene/C60 devices. Sci Rep, 2016, 6: 25331 CrossRef PubMed ADS Google Scholar

[11] Tang X, Hu Y, Jia W, et al. Intersystem crossing and triplet fusion in singlet-fission-dominated rubrene-based OLEDs under high bias current. ACS Appl Mater Interfaces, 2018, 10: 1948-1956 CrossRef Google Scholar

[12] Zhang Z L, Jiang X Y, Xu S H, et al. The effect of rubrene as a dopant on the efficiency and stability of organic thin film electroluminescent devices. J Phys D-Appl Phys, 1998, 31: 32-35 CrossRef ADS Google Scholar

[13] Di D, Yang L, Richter J M, et al. Efficient triplet exciton fusion in molecularly doped polymer light-emitting diodes. Adv Mater, 2017, 29: 1605987 CrossRef PubMed Google Scholar

[14] Liu S, Li B, Zhang L, et al. Enhanced efficiency and reduced roll-off in nondoped phosphorescent organic light-emitting devices with triplet multiple quantum well structures. Appl Phys Lett, 2010, 97: 083304 CrossRef ADS Google Scholar

[15] Jia W, Chen Q, Chen L, et al. Molecular spacing modulated conversion of singlet fission to triplet fusion in rubrene-based organic light-emitting diodes at ambient temperature. J Phys Chem C, 2016, 120: 8380-8386 CrossRef Google Scholar

[16] Zhang Y, Forrest S R. Triplets contribute to both an increase and loss in fluorescent yield in organic light emitting diodes. Phys Rev Lett, 2012, 108: 267404 CrossRef PubMed ADS Google Scholar

[17] Chen P, Lei Y L, Song Q L, et al. Magnetoelectroluminescence in tris (8-hydroxyquinolato) aluminum-based organic light-emitting diodes doped with fluorescent dyes. Appl Phys Lett, 2009, 95: 213304 CrossRef ADS Google Scholar

[18] Lei Y L, Zhang Y, Liu R, et al. Driving current and temperature dependent magnetic-field modulated electroluminescence in Alq3-based organic light emitting diode. Org Electron, 2009, 10: 889-894 CrossRef Google Scholar

[19] Tian X, Zhou L, Chen X, et al. Nanoscale exponential distance dependence and electron-transfer model for intermolecular singlet exciton fission observed in rubrene-doped organic films. Org Electron, 2017, 50: 429-434 CrossRef Google Scholar

[20] Li J, Chen Z, Zhang Q, et al. Temperature-dependent singlet exciton fission observed in amorphous rubrene films. Org Electron, 2015, 26: 213-217 CrossRef Google Scholar

[21] Jankus V, Snedden E W, Bright D W, et al. Competition between polaron pair formation and singlet fission observed in amorphous rubrene films. Phys Rev B, 2013, 87: 224202 CrossRef ADS Google Scholar

[22] Seo J H, Park D S, Cho S W, et al. Buffer layer effect on the structural and electrical properties of rubrene-based organic thin-film transistors. Appl Phys Lett, 2006, 89: 163505 CrossRef ADS Google Scholar

[23] Park S W, Choi J M, Lee K H, et al. Amorphous-to-crystalline phase transformation of thin film rubrene. J Phys Chem B, 2010, 114: 5661-5665 CrossRef PubMed Google Scholar

[24] Kan M, Chen P, Cao S Q, et al. Triplet-triplet annihilation process in organic light-emitting diodes doped with fluorescent dyes (in Chinese). Chin Sin Bull, 2010, 55: 1358-1364 CrossRef Google Scholar

[25] Li J, Chen Z, Lei Y, et al. Competition between singlet exciton fission, radiation, and dissociation measured in rubrene-doped amorphous films. Synth Met, 2015, 207: 13-17 CrossRef Google Scholar

[26] Desai P, Shakya P, Kreouzis T, et al. Magnetoresistance and efficiency measurements of Alq3-based OLEDs. Phys Rev B, 2007, 75: 094423 CrossRef ADS Google Scholar

[27] Yokoyama K, Wakikawa Y, Miura T, et al. Solvent viscosity effect on triplet-triplet pair in triplet fusion. J Phys Chem B, 2015, 119: 15901-15908 CrossRef PubMed Google Scholar

[28] Zhang Y, Liu R, Lei Y L, et al. Prompt fluorescence and delayed fluorescence in Alq3-based organic light-emitting diode (in Chinese). Sci Sin-Phys Mech Astron, 2010, 40: 416-424 CrossRef Google Scholar

[29] Deng J, Jia W, Chen Y, et al. Guest concentration, bias current, and temperature-dependent sign inversion of magneto-electroluminescence in thermally activated delayed fluorescence devices. Sci Rep, 2017, 7: 44396 CrossRef PubMed ADS Google Scholar

[30] Luo Y, Aziz H, Klenkler R, et al. Temperature dependence of photoluminescence efficiency in doped and blended organic thin films. Chem Phys Lett, 2008, 458: 319-322 CrossRef ADS Google Scholar

[31] Ingram G L, Nguyen C, Lu Z H. Long-range energy transfer and singlet-exciton migration in working organic light-emitting diodes. Phys Rev Appl, 2016, 5: 064002 CrossRef ADS Google Scholar

  • Click to view Download high-quality image

    Figure 1

    (Color online) The I-V curves, structure schematic, EL spectra of devices, normalized PL spectra and absorption spectra of materials. (a) The I-V curves of devices B and C1, the inset is the structure schematic of device; (b) the normalized PL spectra of Alq3 and CBP films, the normalized EL spectra of devices A, B, and C1, as well as the normalized absorption spectrum of rubrene film; (c) the temperature-dependent normalized EL spectra of device B.

  • Click to view Download high-quality image

    Figure 2

    (Color online) Current-dependent MEL curves of devices A, B, and C1 at 300?K and 20?K. (a), (b) Device A; (c), (d) device B; (e), (f) device C1.

  • Click to view Download high-quality image

    Figure 3

    (Color online) Temperature-dependent MEL curves of devices at 50?μA. (a) Device A; (b) device B; (c) device C1; (d) device C2.

  • Click to view Download high-quality image

    Figure 4

    (Color online) Low-filed effects of MEL curves varying with injected currents and temperature in different devices. (a) Current-dependent low-filed effects of devices A, B, and C1 at 300?K and 20?K, solid dots denote the variation corresponding to 300?K, hollow dots represent the variation corresponding to 20?K; (b) temperature-dependent low-field effects of devices A, B, C1 and C2 at 50?μA.

  • Click to view Download high-quality image

    Figure 5

    (Color online) Energy diagrams and microscopic processes of devices. (a) The energy diagram of device A; (b) the schematic of microscopic process in device A; (c) the energy diagram of device B and C1; (d) the schematic of energy transfer and microscopic process in device B and C1.

Copyright 2019 Science China Press Co., Ltd. 科学大众杂志社有限责任公司 版权所有

京ICP备18024590号-1