Carbazole/Sulfone Hybrid D-π-A-Structured Bipolar Fluorophores for High-Efficiency Blue-Violet Electroluminescence

Abstract

Based on a D-π-A structural strategy incorporating carbazole as a mild electron-donor and sulfone as an electron-acceptor with a π-conjugation-breaking feature, two novel blue-violet emitting materials (CzS1 and CzS2) were successfully designed and synthesized. The two compounds exhibit high-efficiency fluorescent emissions of intramolecular charge-transfer transition type, with impressively high quantum yields in both solution and film states. CIE y below 0.06 and excellent current/power efficiencies up to 1.89 cd A–1/1.58 lm W–1 were achieved with their corresponding nondoped devices. These performances currently represent the best results for OLEDs with CIE y < 0.06. Moreover, single-carrier devices were also fabricated to demonstrate the bipolar characteristics as well as to understand the different electroluminescence performance of the two fluorophores.

Thermally activated delayed fluorescence materials based on benzophenone derivative as emitter for efficient solution-processed non-doped green OLED

“…Solutioneprocessed and nonedoped OLEDs have attracted more and more attention [30,31]. Very recently, Lee et al reported solutioneprocessed OLEDs using TADF materials as emitters [9].…”

Blue photoluminescence N-substituted poly(4H-benzo[def]carbazole)s

“…Among three basic colors of blue, green, and red for full-color displays, development of high-efficiency blue-light-emitting materials is important. Because the short-wavelength emission can serve as an excitation source for emissions over the whole visible range [2]. Since the first report on blue PLEDs device which was fabricated with poly(p-phenylene) (PPP) in 1992 [3], a large number of materials for blue-light-emitting have been developed [4][5][6][7][8].…”

Synthesis and Characterization of Fluorene-Based Polymers Having Azine Unit for Blue Light Emission

“…Blue light-emitting materials are of great significance for their unique applications in flat-panel displays and high-density information storage. Especially in full-color displays, the short-wavelength emission can serve as an excitation source for emission over the whole visible range [10]. Therefore, development of high-efficiency blue emitting materials is important.…”

“…Herein, the fluorene sequences were selected as D for the reason of good thermal and electrochemical stability, high fluorescence yield and facile chemical functionalization [13,14], while 1,2,4,5-tetrazine (tetrAz) and 1,3,5-triazine (triAz) were chosen as A for their electron deficiency [12]. …”