有机发光二极管
系统间交叉
亮度
掺杂剂
材料科学
量子效率
二极管
兴奋剂
单重态
光电子学
光化学
化学
纳米技术
光学
激发态
物理
原子物理学
图层(电子)
作者
Changfeng Si,Dianming Sun,Tomas Matulaitis,David B. Cordes,Alexandra M. Z. Slawin,Eli Zysman‐Colman
标识
DOI:10.26434/chemrxiv-2023-93jq8
摘要
The development of high-performance solution-processed red organic light-emitting diodes remains a challenge, particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red solution-processable TADF dendrimers, 2GCzBP, 2DPACzBP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the opto-electronic properties. The reverse intersystem crossing rate constant (kRISC) of the emitters having donors substituted at positions 11 and 12 of the dibenzo[a,c]phenazine (BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACzBP, containing stronger donors than 2GCzBP, exhibits a red-shifted emission and smaller singlet−triplet energy splitting, EST, of 0.01 eV. The solution-processed OLED with 10 wt% 2DPACzBP doped in mCP emitted at 640 nm and showed a maximum external quantum efficiency (EQEmax) of 7.8%, which was effectively maintained out to a luminance of 1000 cd m−2. Such a device performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4CzIPN as an assistant dopant in a hyperfluorescence (HF) configuration, where the 2DPACzBP HF device shows an EQEmax of 20.0% at EL of 605 nm and remains high at 11.8% at a luminance of 1000 cd m−2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.
科研通智能强力驱动
Strongly Powered by AbleSci AI