Pyrimidine-based twisted donor–acceptor delayed fluorescence molecules: a new universal platform for highly efficient blue electroluminescence

Abstract

High-efficiency deep blue thermally activated delayed fluorescence (TADF) emitters consisting of acridan–pyrimidine donor–acceptor motifs are developed.

Combining Charge‐Transfer Pathways to Achieve Unique Thermally Activated Delayed Fluorescence Emitters for High‐Performance Solution‐Processed, Non‐doped Blue OLEDs

“…[1][2][3][4][5][6] Utilization of TADF emitters provide an opportunity not only to reduce the overreliance on expensive precious metals for efficient OLEDs, but also to solve the urgent issue of developing stable and efficient blue materials and their devices. [2][3][4][10][11][12][13] While great progress has been made,s ome key challenges remain to be tackled. [2][3][4][10][11][12][13] While great progress has been made,s ome key challenges remain to be tackled.…”

“…[7][8][9] During recent years,h ighly efficient blue TADF materials have been reported. [2][3][4][10][11][12][13] While great progress has been made,s ome key challenges remain to be tackled. One of the major issues is how to balance the DE ST (S 1 -T 1 energy gap) and the transition dipole moment in the design of TADF materials.…”

Recent progress of pyrimidine derivatives for high-performance organic light-emitting devices

“…10). 30,72,76 pyrimidine-based blue TADF OLEDs at this stage: (i) long-term stability at practical luminance, (ii) efficiency roll-off at high brightness, and (iii) low-driving voltage.…”

“…Park et al 76 developed a new family of pyrimidine-based blue emitters using spiroacridine as a donor unit. 2,4,6-Triphenyl pyrimidine and 2-phenyl pyrimidine are used for the acceptor units, and the emission peaks of MFAc-PPM, MXAc-PPM, MFAc-PM, MXAc-PM, and Ac-PM doped PPF films are located at the range of 457 to 466 nm.…”

“…6(b), the reported molecular design strategy of pyrimidine derivatives as TADF emitters is shown. Pyrimidinebased TADF emitters are mainly categorized into donor-acceptor-donor (D-A-D) [68][69][70][71][72] and donor-acceptor (D-A) 29,[73][74][75][76] types, where the pyrimidine backbone is used as the acceptor unit, and phenoxazine, acridine, and carbazole derivatives are frequently used as donor units. Among D-A-D types, the donor unit is attached to the 4,6-position of pyrimidine, whereas among D-A types, the donor unit is attached to the 2-position or the 4-position of pyrimidine.…”