Organic fluorophores that emit ultraviolet light in the aggregated state

Abstract

Ultraviolet (UV)-emissive organic light-emitting diodes (OLEDs) have attracted growing attention as future UV-lighting sources following UV-LED. The design and development of highly efficient UV-emissive organic solids are essential for the advancement of UV-OLEDs. Reviewed herein are organic small molecules and polymers that exhibit UV emission in the aggregated state such as crystal, powder, and amorphous film. The UV-emissive molecules are in principle limited to those whose photoluminescence (PL) maxima are less than 400 nm and whose PL quantum yields in the aggregated state, which are useful for evaluating the potential of solid-state emitters, are reported. In cases that electroluminescence (EL) studies are demonstrated, the emission maxima and external quantum efficiencies with the device structures are also shown. Some exceptions are also included whose PL quantum yields are not reported, but UV-EL with an emission maximum of less than 400 nm is demonstrated.

Disilane-bridged architectures: an emerging class of molecular materials

“…It may have found potential application as deep-blue organic emitters. 62 Recently, a series of disilane bridged bis-TPE (tetraphenylethylene) 14 and bis-TPT (triphenylvinylthiophene) 15 were developed by us to study the electronic and conformational effect of a silane chain on the photophysical properties of aggregation induced emission (AIE) luminogens. 26,63 The absorption spectrum proles of 14 and 15 were found to be the same as that of terminal TPE and TPT, indicating that disilane possesses excellent ability to maintain the original color.…”

“…However, in the sixmembered ring the Si-Si-C(naphthyl) bond angle is unusually restricted to 92.47°, which is signicantly smaller than the idealized value of 109.5°for sp 3 -hybridized silicon. The significant strain imposed by the reduced bond angle in the disilanylene moiety of 71 suggests that its Si-Si bond is highly reactive compared to that of other disilanylene-bridged compounds (59)(60)(61)(62)(63).…”

A large-scale deep-blue tetraphenylbenzene-bridged hybridized local and charge transfer fluorophore exhibiting small efficiency roll-off and low amplified spontaneous emission threshold

“…Such a phenomenon was reported frequently in D-A type molecules. [26][27][28][29] To further study the properties of the excited state, UV-Visible absorption and PL spectra of PTPC in various solvents are recorded and are shown in Fig. S5 (ESI †).…”

“…These properties are beneficial to construct pure blue emitters by linking appropriate electron-donating and accepting groups. [27][28][29] However, It is difficult to build high-performance non-doped deep-blue OLEDs with CIEy o 0.06 and EQE Z 5%. 30 What's more, the efficiency roll-off at high luminance needs to be improved in the 1,2,4,5-TPB-based OLEDs.…”

Indolo[3,2,1-jk]carbazole-Derived Narrowband Violet–Blue Fluorophores: Tuning the Optical and Electroluminescence Properties by Chromophore Juggling

“…The development of innovative organic functional materials has gained everlasting interest from researchers as they exhibit versatile applications in optoelectronics such as organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), sensors, organic field-effect transistors (OFETs), nonlinear optics, and so forth. − Undeniably, OLEDs have emerged as one of the fascinating technologies because of their low cost and promising applications in future display and general lighting. − Thus, tremendous efforts have been devoted to understand the structure–function relationships of organic luminescent materials used as active layers in OLEDs. − Generally, the nature of building blocks and chromophore linking mode play a pivotal role in regulating the optical and electrical parameters. − Thus, understating the structure–property relationships and mastering the tactics of controllably tuning the functional properties of organic luminescent materials is essential. Over the years, substantial progress has been made in the development of the three primary color (blue, green, and red) emitters for OLEDs, and now, they have been receiving commercial attention as well. − Recently, studies on both ends of the visible spectrum such as violet and near infrared regions have aroused increasing attention for OLEDs. − <...…”