All-Solution-Processed Multilayered White Polymer Light-Emitting Diodes (WPLEDs) Based on Cross-Linked [Ir(4-vb-PBI)₂(acac)]

Abstract

All-solution-processed multilayered white polymer light-emitting diodes (WPLEDs) are promising candidates for low-cost and large-area flexible full-color flat-panel displays and solid-state lighting. However, it is still challenging to improve their performance. In this work, based on an elegant strategy of orthogonal materials, the utilization of the cross-linked Ir3+ polymer film poly­(NVK-co-[Ir­(4-vb-PBI) 2 (acac)]- co -NVK) (NVK = N-vinyl-carbazole; 4-vb-HPBI = 1-(4-vinylbenzyl)-2-phenyl-1H-benzo­[d]­imidazole; and Hacac = acetylacetone) as the emitting layer (EML) between a hydrophilic polymer film poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) as the hole injection layer (HIL) and a hydrophobic polymer film poly­(vinyl-PBD) (vinyl-PBD = 2-(4-(tert-butyl)­phenyl)-5-(4′-vinyl-[1,1′-biphenyl]-4-yl)-2,5-dihydro-1,3,4-oxadiazole) as the electron transport layer (ETL) led to the successful fabrication of reliable all-solution-processed multilayered WPLEDs. The device exhibits a ηCE Max of 18.19 cd/A, a ηPE Max of 8.16 lm/W, and a ηEQE Max of 9.32% with stable white light (Commission International De L’Eclairage (CIE) coordinates x = 0.269–0.283, y = 0.317–0.330; corrected color temperatures (CCTs) of 7237–8199 K, and CRIs (color rendering indices) of 63–72) under a wide applied-voltage range. Its high performance, especially with record efficiencies among those of reported all-solution-processed WPLEDs, renders cross-linked Ir3+ polymers a new platform to all-solution-processed multilayered WPLEDs.

Standard White CP‐OLEDs Performance Achieved by Intramolecular Chirality Transfer Mechanism through Polymer Chain

“…[15][16][17] In particular, much interest has been received on polymer-based WOLEDs due to their flexible display, simple device fabrication, low-cost solution-processed technologies, and ability for large area manufacturing. [18][19][20] Recently, Ying's group introduced simple bilayer structure WPLEDs with a ternary blend layer containing polyfluorene derivatives of blue light-emitting PFO-TF, green light-emitting PFO-BT8, and red light-emitting PFO-DHTBT5, and the resulting devices exhibited a color-tunable white lighting maximum current efficiency of 9.22 cd A −1 . [21] Very recently, Wong's group produced single Zn(II)-complex-grafted polymer poly(NVK-co-[Zn 2 (MP) 3 (OAc)])-based WPLEDs-emitting stable white light (CIE coordinates of x = 0.30, y = 0.33) at different driving voltages.…”

Two‐Color Strip‐Patterned White OLEDs: Tunable Color‐Temperature via Pattern Dimension Control

“…Solution processes are considered promising alternatives for achieving large-area uniform organic films through cost-effective methods. [6][7][8][9][10][11] However, new technical challenges arise when a solution process is applied to form the active layer of WOLEDs that requires the use of mixed colors. A blend solution of luminophores combining various colors may be processed to form the WOLED active layer.…”