Impacts of dopant concentration on the carrier transport and recombination dynamics in organic light emitting diodes

Feng, Shih‐Wei; Shih, Ming‐Chang; Huang, Chien Jung; Chung, Chia-Tin

doi:10.1016/j.tsf.2008.10.049

Cited by 14 publications

(15 citation statements)

References 21 publications

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“…Organic semiconductors are presently a field of intensive research due to their application in organic field-effect transistors, organic light-emitting diodes (OLEDs) [1], flexible displays [2], and flexible solar cells [3]. Organic semiconductors offer the possibility of tailoring the chemical structure to adapt the material functionally and improve device performance.…”

Section: Introductionmentioning

confidence: 99%

“…Device applications of disordered OLEDs often require doping of these materials to achieve a higher density of free carriers [4][5][6][7], efficient color tuning, good device efficiency, and narrow emission spectrum width [1][2][3]. Doping of an energetically disordered hopping system not only produces free charge carriers, but also creates localized (relatively deep) states in addition to the intrinsic DOS distribution [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Dependence of the dynamics of exciton transport, energy relaxation, and localization on dopant concentration in disordered C545T-doped Alq_3 organic semiconductors

Feng

2014

Opt. Mater. Express

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The dynamics of exciton transport, energy relaxation, and localization in disordered Tris(8-quinolinolato)-aluminum (Alq 3) organic semiconductors with different 10-(2-benzothiazolyl)-1, 1, 7, 7-tetramethyl-2, 3, 6, 7-tetrahydro-lH, 5H, 11H-benzo[l] pyrano[6, 7, 8-і ј] quinolizin-11one (C545T) dopant concentrations were reported. The increasing trend of the Stokes Shift (737~764 meV) with increasing dopant concentrations is consistent with the degree of disorder and a more effective Förster energy transfer from Alq 3 to C545T. In addition, a dynamic scenario representing possible paths of the exciton transport (hopping) among host molecules and the competition of the exciton transport from host molecules into the deep site traps (localized states) and aggregations was proposed to elucidate the recombination dynamics in disordered C545T-doped Alq 3 organic semiconductors. The early-stage decay times, decreasing with increasing emission photon energy, show the characteristic of the exciton hopping and energy relaxation processes within the inhomogeneously broadened density-of-states in organic semiconductors. Because the current-voltage (J-V) characteristics of the C545T-doped organic light emitting diode (OLED) fitted well with the power law J~V m (m>2), the carrier transport behaviours can be described by the trapped-control mode and the tail state distribution can be approximated by the exponential trap distribution. With the approximation of an exponential distribution for the tail states, the characteristic energy (E m), radiative recombination lifetime (τ rad), and localization depth (E 0) associated with the dynamics of exciton energy relaxation and localization can be quantitatively determined. The much larger E 0 (40~120 meV), increasing with the dopant concentration, than other disordered semiconductors (2~34 meV) indicates a strong localization effect in such doped organic semiconductors. Also, the strong dependence of E m on the dopant concentration shows that a relatively small dopant concentration can enhance the degree of disorder and greatly affect the recombination dynamics. Furthermore, the observed optical properties and dynamic scenario of C545T-doped Alq 3 films are found to be consistent with the carrier transport and recombination dynamics of C545T-doped Alq 3 OLEDs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dependence of the dynamics of exciton transport, energy relaxation, and localization on dopant concentration in disordered C545T-doped Alq_3 organic semiconductors

Feng

2014

Opt. Mater. Express

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“…Moreover, response time of the device with the CSC-EIS became a constant within the large voltage pulses range (V pulses Z7 V). The constant response time suggests that the saturation of carrier mobility can be faster achieved than that of the device with the CEIS [11]. In addition, response time of the devices with the CEIS and the CSC-EIS at 4 V is 2.02 and 0.91 μs, respectively.…”

Section: Resultsmentioning

confidence: 94%

Enhanced radiative decay in organic light-emitting diodes by combination of cesium carbonate and silver nanocluster

Chen

Gao

Chen

et al. 2015

Journal of Luminescence

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“…发光增强 [1] , 表现为在外加较小磁场下快速增加的 MEL; 同时, 由于 1 PP较 3 PP的离子性更强, 1 PP还可以解离为自由电子空穴, 从而使器件电流增加 [29] , 表 http://engine.scichina.com/doi/10.1360/N972018-00434 材料和客体材料之间存在 Förster和 Dexter能量转移 [16] . 因此 [31,32] . 因此器件中TQA反应强度 [12] .…”

Section: 本文选用 a L Q 3 作为掺杂主体 T A D F 材料 4cztpn-ph作为掺杂客体制unclassified

Abnormal magnetic field effects in doped organic light-emitting devices

Deng¹,

Tang²,

Pan³

et al. 2018

Chin. Sci. Bull.

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Impacts of dopant concentration on the carrier transport and recombination dynamics in organic light emitting diodes

Cited by 14 publications

References 21 publications

Dependence of the dynamics of exciton transport, energy relaxation, and localization on dopant concentration in disordered C545T-doped Alq_3 organic semiconductors

Dependence of the dynamics of exciton transport, energy relaxation, and localization on dopant concentration in disordered C545T-doped Alq_3 organic semiconductors

Enhanced radiative decay in organic light-emitting diodes by combination of cesium carbonate and silver nanocluster

Abnormal magnetic field effects in doped organic light-emitting devices

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