Design of efficient thermally activated delayed fluorescence blue host for high performance solution-processed hybrid white organic light emitting diodes

Abstract

A highly efficient solution-processible TADF blue host is developed by molecular encapsulation. Due to the steric shield effect of the peripheral units, the triplet–triplet and triplet–polaron quenching of the TADF blue host are restricted.

Highly Efficient and Solution‐Processed Single‐Emissive‐Layer Hybrid White Organic Light‐Emitting Diodes with Tris(triazolo)triazine‐Based Blue Thermally Activated Delayed Fluorescence Emitter

“…[ 31–34 ] With this in mind, great attention is focused on realizing WOLEDs by adopting TADF molecules as emissive dopants or assistant hosts. [ 35,36 ] For instance, Li and co‐workers designed several solution processable TADF‐P hybrid WOLEDs employing blue TADF dendrimers as the host and the orange phosphorescent molecule of (Ir(bt) 2 (acac) (bis(2‐phenylbenzothiazolato) (acetylacetonate)iridium (III)) as the guest and observed a maximum EQE (EQE max ) of 10.1%. [ 37 ] This inferior device performance could be mainly ascribed to the severe concentration quenching in the TADF host.…”

Recent progress in thermally activated delayed fluorescence emitters for nondoped organic light-emitting diodes

“…Moreover, such "emission-core and host-encapsulation" molecular structures generally meet the requirements of the solution process and are thus usually applied in solution-processed nondoped OLEDs. 47,48 It was recently recognized that some organic emitters actually have dual stable conformations. TADF is associated with the highly twisted conformation, which is also known as the "quasi-equatorial (QE)" conformation.…”

“…Moreover, such “emission-core and host-encapsulation” molecular structures generally meet the requirements of the solution process and are thus usually applied in solution-processed nondoped OLEDs. 47,48…”

Manipulating Förster and Dexter interactions between a thermally activated delayed fluorescence host and a phosphorescent dopant for highly efficient solution-processed red and white OLEDs

“…[12][13][14][15] For multilayered device fabrication, the issue of orthogonal solvents remains a great challenge. 13,16 Therefore, the EL performances of most solution-processed OLEDs are inferior, [17][18][19] lagging far behind those of their vacuum-deposited counterparts. [4][5][6][7][8][9][10] It is urgent to develop highly efficient solution-processed emitting layers with a simple structure.…”