Azasiline-based thermally activated delayed fluorescence emitters for blue organic light emitting diodes

Abstract

Azasiline-based blue thermally activated delayed fluorescence emitters for blue fluorescent organic light emitting diodes.

Cyclophane Molecules Exhibiting Thermally Activated Delayed Fluorescence: Linking Donor Units to Influence Molecular Conformation

“…[12][13][14] State-of-the-art emitter molecules, which are based on the thermally activated delayed fluorescence (TADF) principle can exploit up to 100% of the excitons formed under optical or electrical excitation. [15][16][17][18][19][20][21] Here, triplet excited states are converted to singlet states through a harvesting mechanism known as reverse intersystem crossing (RISC). [22][23][24][25][26][27][28][29] Molecules exhibiting TADF are generally comprised of donor (D) and acceptor (A) segments, which are electronically decoupled, inducing a high degree of twist between the D-A segments.…”

Deep-Blue Oxadiazole-Containing Thermally Activated Delayed Fluorescence Emitters for Organic Light-Emitting Diodes

“…Since this report, other analogues based on DPS acceptors have been reported, many reaching EQEmax values in excess of 10%. [34][35][36][37][38] Employing a related TADF emitter based on a dibenzo-fused phosphacycle acceptor produced a somewhat poorer performance in the device, with EQEmax of 4.9% and CIE at (0.15, 0.16). 39 Hatakeyama et al 40 designed an interesting class of deepblue TADF emitters based on a "multiple resonance effect", which produced narrow-band emission spectra with CIE at (0.13, 0.09) and an EQEmax of 13.5%.…”

Thermally Activated Delayed Fluorescence Emitters for Deep Blue Organic Light Emitting Diodes: A Review of Recent Advances

“…These design rules constitute a second key-element for the design of TADF emitters. In the work of Sun et al [79], the highly twisted structure of 8 contributed to reduce ∆E ST , improve the colour purity, and enhance the electroluminescence device performances. Benefiting from these favourable features, 8 furnished deep blue OLEDs with colour coordinates of (0.15, 0.11).…”

“…This study provides several interesting elements for the molecular conception of TADF emitters and the deep blue dendrimers that are reported in this work are promising candidates for the design of solution-processed OLEDs. In the search for new structures, Sun et al used azasiline as a donor in combination with DPS to construct a push-pull deep blue emitter (compound 8) with colour coordinates of (0.15, 0.11) [79]. Carbazole has been considered during decades as an excellent donor for the design of light-emitting materials and a huge number of carbazole-based blue emitters have been reported in the literature.…”

“…This strategy also efficiently prevents intermolecular interactions and drastically reduces the conformation disorder. Sun et al synthetized two triazine/azasiline emitters (12 and 13, Figure 3) [79]. Structurally, 12 differs from 13 by the length of the π-conjugated bridge.…”