Realization of efficient light out-coupling in organic light-emitting diodes with surface carbon-coated magnetic alloy nanoparticles

Abstract

A significant enhancement in light extraction in organic light-emitting diodes (OLEDs) is realized by using composite hole transport layers (HTLs) with surface carbon-coated magnetic alloy nanoparticles (NPs). Compared to the control device with a standard architecture, the current efficiencies of fluorescent green OLEDs can be enhanced by 47.1% and 48.5% by mixing the surface carbon-coated magnetic FePt (0.5 wt‰) and CoPt (0.5 wt‰) alloy NPs into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), yielding the maximum values of 5.40 cd A and 5.45 cd A, respectively. The presence of an alloy NP-incorporated PEDOT:PSS HTL also acts as an optical out-coupling layer contributing to the efficiency enhancement, accomplished through the collective effects of light-scattering, localized surface plasmon resonance and increased electron trap density induced by magnetic alloy NPs.

Recent Advances in the Optimization of Organic Light‐Emitting Diodes with Metal‐Containing Nanomaterials

“…Recently, our group reported the achievement of a significant enhancement in light extraction of OLEDs by using the composite HTL with surface carbon-coated magnetic ANPs. [89] As shown in Figure 18, the current Figure 14. The distribution of the electric field intensity in (a) a 40 nm thick TCTA and (b) a 40 nm thick TCTA with a layer of the embedded Ag NPs located in the centre of HTL.…”

“…(a) Schematic drawing illustrating the device structure of OLEDs with a PEDOT:PSS/magnetic NPs hybrid HTL, (b) relative EL intensity versus current density, (c) EQE versus brightness, and (d) normalized EL spectral characteristics measured for the control device, FePt doped, and CoPt doped devices. [89] Copyright © 2017, The Royal Society of Chemistry . 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 magnetic NPs (MNPs) enhanced significantly in the longitudinal direction (x-axis) and the magnetic field intensity increased along the light travel direction (z-axis).…”

Micro Organic Light Emitting Diode Arrays by Patterned Growth on Structured Polypyrrole

“…Theoretically, light extraction efficiency is only 20% in a standard device architecture on ITO glass, while the other 80% of the emitted light is lost through electrode absorption and plasmon at the metal electrode–organic interfaces, as well as the waveguide mode and substrate mode. [ 19,20 ] In the case, the electrode materials play a crucial role to improve the light extraction. To improve the light extraction of micro OLEDs fabricated by patterned growth, ideally the nucleation layer should compose high transparent and non‐metal materials to minimize electrode absorption and interface plasmon, respectively.…”

Conductive ITO Interfaces for Optoelectronic Applications Based on Highly Ordered Inverse Opal Thin Films

“…Several authors discuss positive effects of random and ordered structures out‐coupling layers on organic light emitting diodes . Such layers are often fabricated with further extraneous materials like polymers, metal oxides or carbons . However, with each additional layer extensive optimization steps for the stack are required.…”

“…[8][9][10][11][12][13][14] Such layers are often fabricated with further extraneous materials like polymers, metal oxides or carbons. [15][16][17][18] However, with each additional layer extensive optimization steps for the stack are required. By structuring the ITO anode material itself, these steps might become superfluous.…”