The synthesis, crystal structures, aggregation-induced emission and electroluminescence properties of two novel green-yellow emitters based on carbazole-substituted diphenylethene and dimesitylboron

• Two compounds based on diphenylethene framework were synthesized and characterized by single crystal X-ray diffraction.
• They exhibit aggregation-induced emission (AIE) properties.
• Efficient multi-layer non-doped electroluminescent devices fabricated with them show good electroluminescent performances.

Introducing the hole-transporting carbazole moiety into an aggregation-induced emissive tetraarylethene skeleton and attaching electron-transporting dimesitylboron groups to the periphery, we obtain two novel electroluminescent materials. Their structures are fully characterized by elemental analysis, mass spectrometry, NMR spectroscopy and X-ray crystallography. Furthermore, their thermal, electrochemical, as well as photophysical properties including AIE-behavior are systematically investigated not only by experimental methods but also by DFT computation. Thereby, we show that the two compounds possess high thermal and electrochemical stability with a remarkable AIE-behavior. X-ray crystal analyses aided by DFT calculations provide insights in the origin of the luminescent properties and AIE features. Ultimately, two non-doped OLEDs (Device A and Device B) were fabricated by using PDPBCE and BDPBCE as light-emitting layer, respectively. Device A showed yellowish-green light with a turn-on voltage of 3.8 V, a maximum brightness of 59130 cd m−2 and a maximum current efficiency of 6.43 cd A−1. Device B exhibited greenish-yellow light with a turn-on voltage of 3.0 V, a maximum brightness of 67,500 cd m−2 and a maximum current efficiency of 11.2 cd A−1.

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