Trade-Offs between Illumination and Modulation Performances of Quantum-Dot LED

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Original languageEnglish
Article number9091881
Pages (from-to)726-729
Journal / PublicationIEEE Photonics Technology Letters
Issue number12
Online published12 May 2020
Publication statusPublished - 15 Jun 2020


We investigate the effects of the hole transport layer (HTL) and the buffer layer in a CdSe/ZnS quantum-dot LED (QLED) to reveal several important performance trade-offs in the QLED design. Our fabricated QLED samples show that, among the three common HTL materials, poly(9-vinlycarbazole) (PVK), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPD), and poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl)) diphenylamine) (TFB), PVK provides the highest luminance of 1.0× 105 cd/m2, but the smallest modulation bandwidth of 2.0 MHz, while TFB provides the lowest luminance of 5.8× 104 cd/m2, but the largest bandwidth of 6.5 MHz. For each HTL material, there exists an optimal HTL thickness for the illumination performance, but the bandwidth decreases with an increase in the HTL thickness. The incorporation of a LiF buffer layer in a QLED can significantly increase the luminance, but at the expense of the modulation bandwidth. Our results are useful for the design of QLEDs for visible light communication applications.

Research Area(s)

  • modulation bandwidth, Quantum-dot light-emitting diode, visible light communication