Fluorescence quenching and enhancement of vitrifiable oligofluorenes end-capped with tetraphenylethene
作者:Matthew P. Aldred、Chong Li、Guo-Feng Zhang、Wen-Liang Gong、Alexander D. Q. Li、Yanfeng Dai、Dongge Ma、Ming-Qiang Zhu
DOI:10.1039/c2jm30261f
日期:——
We report the synthesis of novel amorphous fluorene-based fluorophores that have been end-capped with tetraphenylethene (TPE). Although in the solid state the fluorophores show bright cyan fluorescence with high (68%) photoluminescence quantum efficiency (PLQE), strong fluorescence quenching is observed in solution with low PLQE values ranging from 0.3% to 2.1%. When the fluorophores were added to a 90% water–THF solvent mixture nanoparticles were formed, which was confirmed by Dynamic Light Scattering (DLS) and Atomic Force Microscopy (AFM). Subsequent fluorescence measurements reveal that all the fluorophores exhibit aggregation induced emission (AIE) with high PLQE (41%). We have carried out a comparative study of 5 fluorene-based TPE materials (F(1–5)TPE), in which the fluorene core is extended, and investigated their thermal, optical, electrochemical and electroluminescence properties. From fluorescence quantum yield data we have discovered that the AIE effect decreases as the fluorene core increases both in the nanoparticle and in the solid state. Thermal analysis reveals that all fluorophores are amorphous with high thermal stabilities. Potential application in solid state vapour sensing has been demonstrated using dichloromethane that shows “on” and “off” fluorescence behaviour. Finally, Organic Light Emitting Diodes (OLEDs) have been fabricated with device configuration ITO/PEDOT/F(1–5)TPE/TPBi/LiF/Al. The best OLED device that incorporates F1-TPE as the emitter exhibits a turn-on voltage of 5.8 V, Lmax = 1300 cd m−2, ηP,max = 1 lm W−1 and ηC,max = 2.6 cd A−1.
我们报告了用四苯基乙烯(TPE)封端的新型无定形芴基荧光团的合成。虽然这些荧光团在固态下显示出明亮的青色荧光,且光致发光量子效率(PLQE)较高(68%),但在溶液中却观察到强烈的荧光淬灭,PLQE 值较低,从 0.3% 到 2.1%。将荧光团加入 90% 的水-THF 溶剂混合物中后,形成了纳米颗粒,动态光散射(DLS)和原子力显微镜(AFM)证实了这一点。随后的荧光测量显示,所有荧光团都表现出聚集诱导发射(AIE)和较高的 PLQE(41%)。我们对 5 种芴基热塑性弹性体材料(F(1-5)TPE)进行了比较研究,其中芴芯被延长,并调查了它们的热学、光学、电化学和电致发光特性。我们从荧光量子产率数据中发现,在纳米粒子和固态中,随着芴核的增加,AIE 效应会减弱。热分析表明,所有荧光团都是无定形的,具有很高的热稳定性。利用二氯甲烷显示出 "开 "和 "关 "荧光行为,证明了其在固态蒸汽传感中的潜在应用。最后,利用器件配置 ITO/PEDOT/F(1-5)TPE/TPBi/LiF/Al,制造出了有机发光二极管(OLED)。采用 F1-TPE 作为发射器的最佳 OLED 器件的开启电压为 5.8 V,Lmax = 1300 cd m-2,ηP,max = 1 lm W-1,ηC,max = 2.6 cd A-1。