Multi-Colored Light-Emitting Electrochemical Cells Based on Thermal Activated Delayed Fluorescence Host

Abstract

Light-emitting electrochemical cells (LECs) with the thermally activated delayed fluorescence(TADF) host and phosphorescent guests were fabricated using solution process. It is demonstrated for the first time that TADF, a well-known phenomenon that helps to increase electroluminescence efficiency by harvesting excitons from triplet states, is used as a host in LECs. Devices with green, yellow, red and warm white emissions were fabricated, with the best devices showing more than 7000 cd/m2 stable emission and a peak efficiency over 7 cd/A. Under high voltage stress, a burst of extremely high luminance of over 30,000 cd/m2 was observed. All these LEC devices are extremely simple with only one active layer. Thus, our results could pave way to produce low- cost light source with high luminance, using TADF molecules.

Retracted Article: Facile preparation of bithiazole-based material for inkjet printed light-emitting electrochemical cell

“…[9][10][11] Nevertheless, LECs are simpler than organic light-emitting diodes (OLEDs). 12,13 Due to its single layer architecture, low fabrication price and operating voltages, LECs are considered as a promising, next-generation, emissive thin-lm technology. [14][15][16] The most efficient device used to date for LECs are biscyclometalated iridium(III) (Ir) complexes, because they have highly efficient and stable devices spanning the whole visible range.…”

Phosphane tuning in heteroleptic [Cu(N^N)(P^P)]+complexes for light-emitting electrochemical cells

“…This enables the indirect harvesting of fluorescence from the triplet state, which boosts device performance. 23,24 [Cu(P^P)(N^N)] + complexes in which P^P is bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) (Scheme 1) and N^N is a bpy or phen ligand have been studied systematically in an effort to enhance their photoluminescent properties and device performances. We have investigated the influence of introducing alkyl and phenyl substituents into the 6-and 6,6′ 4 ] on their photo-and electroluminescent properties and found a direct correlation between the σ-Hammett parameters of the R groups in 4,4′-R 2 bpy and the device efficiency.…”

Efficient and Saturated Red Light‐Emitting Electrochemical Cells Based on Cationic Iridium(III) Complexes with EQE up to 9.4 %

“…These promising properties ensure their potential application in low‐cost displays. Among the reported emissive materials used in LECs, for example, polymers, ionic transition metal complexes (iTMCs), small molecules, and quantum dots/nanoparticles, phosphorescent iTMCs usually exhibit the higher electroluminescence (EL) efficiency. Therefore, tremendous effort has been made to improve the device performance of iTMC‐based LECs …”