Boosting external quantum efficiency to 38.6% of sky-blue delayed fluorescence molecules by optimizing horizontal dipole orientation

Abstract

Highly efficient sky-blue organic luminescent materials for the application in organic light-emitting diodes are developed.

New aggregation-induced delayed fluorescent materials for efficient OLEDs with high stabilities of emission color and efficiency

“…In addition, the host materials also significantly influence the EL performances of both luminogens (Table S1, ESI), partially due to the host-tuning effect. 64…”

Management of Multi‐Energy‐Transfer Channels and Exciton Harvesting for Power‐Efficient White Thermally Activated Delayed Fluorescence Diodes

“…[10,[17][18][19][20][21][22] The TADF-based WOLEDs are popularly composed of a single-emissive-layer (SEL) for white light emission, which is constructed by a ternary host:blue sensitizer:yellow dopant system or a binary blue TADF host:yellow dopant system. [14][15][16][17][18][19][20][21][22][23] In these systems, effective energy transfer and emission channels between host and dopants should be built, and the parasitic energy loss should be considerably as small as possible to approach 100% internal quantum efficiency. [16,24] To realize this point, suitable blue sensitizers or host materials play a vital role in the energy transfer of both singlet and triplet excitons.…”

“…[16,24] To realize this point, suitable blue sensitizers or host materials play a vital role in the energy transfer of both singlet and triplet excitons. [14,16] Two distinct modes of energy transfer from blue TADF materials to yellow dopants have been demonstrated to take place, which are determined by their reverse intersystem crossing (RISC) efficiencies (Φ RISC ). Förster resonance energy transfer (FRET) is dominant for the case of Φ RISC of blue emitters higher than that of yellow emitters, whereas Dexter energy transfer (DET) will occupy a very large proportion in the opposite case.…”

“…[12,13] Nevertheless, the PEs of TADF-based WOLEDs reported to date are still considerably below 80 lm W -1 , lagging far behind their phosphor counterparts. [14][15][16] To achieve a power-efficient TADF-based WOLED, reducing energy loss and harvesting all electrically generated excitons during electron-photon conversion are of utmost White organic light-emitting diodes (WOLEDs) based on thermally activated delayed fluorescence (TADF) emitters attract considerable attention owing to the advantages of full exciton harvesting, low cost, and environmental sustainability. However, compared to phosphorescent counterparts, the power efficiencies of TADF-based WOLEDs lag behind.…”

All-fluorescence white organic light-emitting diodes with record-beating power efficiencies over 130 lm W‒1 and small roll-offs

“…The external quantum efficiency (EQE) of monochromatic OLEDs based on TADF emitters have successfully surpassed 30%, and even approached 40% in very recent reports. [8][9][10][11][12] Therefore, certain high-efficiency TADF emitters with competitive prices hold great potentials to replace phosphorescence materials in OLED industry.…”