Synthesis and photophysical characterization of an ionic fluorene derivative for blue light-emitting electrochemical cells

• An ionic fluorene derivative was synthesized and photophysically characterized.
• Synthesized compound shows blue color in solution as well as in solid state.
• Light-emitting electrochemical cells (LECs) were fabricated and devices were characterized.
• LEC based solely on the ionic fluorene derivative as the active components.
• The devices resulted blue color light emission.

A highly fluorescent an ionic fluorene derivative 1 was synthesized and its photophysical, electrochemical and electroluminescence characteristics were investigated. Deep blue emissions were observed for compound 1 in solid as well as in dilute solutions. The synthesized compound shows high fluorescence quantum yield around 77% indicates that compound 1 can perform its role as efficient ionic emitter in LEC devices. Light-emitting electrochemical cell (LEC) devices were fabricated incorporating compound 1 without (device I) and with (device II) ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM·PF6). Devices I and II exhibited blue electroluminescence maximum centered at 455 and 454 nm with CIE coordinates of (0.15, 0.21) and (0.16, 0.22), respectively. Maximum luminance and current efficiency of 1105 cd m−2 and 0.14 cd A−1 respectively, has achieved for device I while that of device II resulted in 1247 cd m−2 and 0.14 cd A−1 respectively.

Blue light-emitting electrochemical cells were constructed by using on ionic organic small molecule which avoids the ion conducting polymer and an additional salt due to the intrinsic ionic nature of the compound.Figure optionsDownload as PowerPoint slide