Toward ultra-high efficiency tandem OLEDs: Benzothiazole-based bipolar hosts and specific device architectures

Perceiving the influence of phenyl-carbazole isomers on sulfone/thioxanthone-based D–A–D hosts: realizing efficient red-phosphorescent OLEDs

“…As indicated, the optical path differences between the tested devices are due to the various locations of the exciton formation regions in the EML, resulting in slight differences in the spectral profiles in the longer wavelength ranges. 56 Notably, all six devices exhibited pristine Ir(piq) 2 acac emission, underscoring the appropriateness of the chosen host–guest systems and confirming that the exciton generation primarily occurred within the EML. Furthermore, given the adequate energy triplet energy bandgap of the co-host systems that effectively facilitate host–guest energy transfer and exciton confinement, no other emissions were observed from the host or the adjunct layers.…”

Sulfonyl-functionalized benzo[d]imidazo[5,1-b]thiazole-based carbenes as building blocks for two-coordinate Cu(i) complexes exhibiting fast and efficient thermally activated delayed fluorescence

“…55 Furthermore, no other emission was observed except for that of compound 3 , indicating that energy transfer from the host to the guest was successfully achieved, and that the exciton was effectively confined within the EML. 56 Our prior research has shown that Cu( i ) CMA complexes featuring thiazoline carbene ligands tend to form emissive aggregates, leading the devices to offer a dual emission from monomers and dimers. 39 This phenomenon was not found in this study despite both CMA emitters sharing a common design approach with a semi-shielded surface of the carbene moiety.…”

Purely Organic Room‐Temperature Phosphorescence Molecule for High‐Performance Non‐Doped Organic Light‐Emitting Diodes

“…The tandem OLED is constructed with two or more independent EL units electrically connected in series by intermediate connectors. Driven by the same current density, tandem OLEDs with N EL units (N > 1) can theoretically provide N times higher luminance compared to single-unit OLEDs, [66,67] namely, tandem OLEDs require 1/ N current density to achieve the same luminance, which is much conducive to improving operational device lifetimes. [68] However, the tandem OLEDs based on purely organic RTP materials are never reported.…”