设计并合成了两个新颖的TADF分子,它们具有施主#1–σ–施主#2–π–受体(D1–σ–D2–π–A)构象,并通过键合电荷转移(TBCT)和空间电荷转移(TSCT)。这两种材料仅在D1组中有所不同,对于SFCCN,三苯胺和对于SFCCNO,是10-苯基-10 H-苯恶嗪。由于存在非共轭键,这两种材料在稀溶液中的发射与D2-π-ATBCT的发射非常相似。SFCCNO可以在聚集状态下形成二聚体,并且由于平面D1构象而表现出分子间D1 / A TSCT发射。因此,基于SFCCNO的非掺杂器件在100 cd m -2的效率为12.9%在1000 cd m -2时为10.4%,远高于基于SFCCN的设备。
用于红色,绿色和蓝色磷光体的通用主体材料为高效磷光有机发光二极管(PHOLED)的制造提出了挑战。本文中,两个螺主体材料,即3-(4,6-二苯基-1,3,5-三嗪-2-基)-9',9'-二甲基-9' ħ -螺[芴9,5' -喹啉[3,2,1-去]啶](QAF-TRZ)和3'-(4,6-二苯基-1,3,5-三嗪-2-基)-10-苯基-10 H-螺设计并合成了[ac啶9,9'-芴](STF-TRZ)。所设计的策略更合适,并且在所报道的基于螺线的有机发光二极管(OLED)骨架中很少发现。两种材料均表现出优异的电致发光性能。特别是基于QAF-TRZ的RGB三色PHOLED以STF-TRZ为主体,以FIrpic,Ir(ppy)2 acac和Ir(MDQ)2 acac作为发射极。基于QAF-TRZ的蓝色PHOLED实现了19.4%的最大外部量子效率(EQE),并在1000 cd m -2时保持17.2
Four novel host materials were designed and synthesized, incorporating fluorene-spiro-annulated triphenylamine–carbazole (ST–SCz) and dibenzothiophene (DBT) blocks. A meta-linking strategy was applied by introducing DBT moieties to ST–SCz skeletons at the C3 position of the fluorene backbones. As expected, high triplet energies (over 2.80 eV) were achieved in all four materials despite the different linking positions on the DBT. All four materials show a high Tg from 149 to 163 °C, which benefits from their spiro-structure. Their thermal, electrochemical and photo-physical properties were fully characterized. Highly efficient blue and white PHOLEDs were fabricated using these four materials as the hosts. Triphenylamine-containing STDBT4 and STDBT2 demonstrate better device performance due to their relatively high-lying HOMO compared to carbazole-containing SCzDBT4 and SCzDBT2. Maximum ηext of 19.6% and 18.4% (STDBT4 and STDBT2) were achieved for FIrpic-based devices, and 23.7% and 22.2% (STDBT4 and STDBT2) were achieved for two color-based white PHOLEDs with double emitting layers, using PO-01 as a yellow dopant. Finally, a highly efficient single-emitting layer white PHOLED with maximum efficiencies of 24.0%, 77.0 cd A−1 and 63.2 lm W−1 and CIE coordinates of (0.38, 0.48) was realized using the device configuration of ITO/HAT–CN/TAPC/STDBT4: 8 wt% FIrpic: 0.8 wt% PO-01/TmPyPB/Liq/Al. The device shows good color stability and low efficiency roll-off. Even at a high luminance of 10 000 cd m−2, it still maintains very high efficiencies of 17.9%, 56.4 cd A−1 and 26 lm W−1.
设计并合成了四种新型宿主材料,结合了氟烯-螺旋关联三苯胺-咔唑(ST–SCz)和二苯并噻吩(DBT)块。采用了一种元链接策略,通过在氟烯骨架的C3位置引入DBT基团到ST–SCz骨架上。正如预期的那样,尽管DBT的链接位置不同,但所有四种材料都达到了高的三重态能量(超过2.80 eV)。这四种材料的玻璃化转变温度(Tg)均较高,从149°C到163°C,得益于其螺旋结构。它们的热、 electrochemical 和光物理性质经过全面表征。使用这四种材料作为宿主,制备了高效的蓝光和白光PHOLED。含三苯胺的STDBT4和STDBT2由于其较高的HOMO能级相比含咔唑的SCzDBT4和SCzDBT2展现出更好的器件性能。FIrpic基器件的最大外量子效率(ηext)分别为19.6%和18.4%(STDBT4和STDBT2),而基于双色的白光PHOLED(双发射层)则分别达到了23.7%和22.2%(STDBT4和STDBT2),使用PO-01作为黄色掺杂剂。最后,一种高效的单发射层白光PHOLED在使用配置为ITO/HAT–CN/TAPC/STDBT4: 8 wt% FIrpic: 0.8 wt% PO-01/TmPyPB/Liq/Al的情况下,实现了最高效率为24.0%、77.0 cd A−1和63.2 lm W−1,CIE坐标为(0.38, 0.48)。该器件显示出良好的色彩稳定性和低效率降幅。即使在高亮度10,000 cd m−2下,仍然保持了非常高的效率,分别为17.9%、56.4 cd A−1和26 lm W−1。
The Control of Conjugation Lengths and Steric Hindrance to Modulate Aggregation-Induced Emission with High Electroluminescence Properties and Interesting Optical Properties
affected the conjugation lengths of these compounds. Consequently, we have obtained molecules with different emission colors and properties without sacrificing good EL (electroluminescence) characteristics. Accordingly, a device that was based on compound SAF‐2‐TriPE displayed superior EL characteristics: it emitted green light with ηc, max=10.5 cd A−1 and ηext, max=4.22 %, whereas a device that was based
The introduction of spiro-acridine-fluorene (SAF) can affect the electronic structure of the whole molecule, which made SAF-based materials exhibit totally different photophysical properties from conventional spirobifluorene-based materials.