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

Abstract

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 454nm with CIE coordinates of (0.15, 0.21) and (0.16, 0.22), respectively. Maximum luminance and current efficiency of 1105cdm−2 and 0.14cdA−1 respectively, has achieved for device I while that of device II resulted in 1247cdm−2 and 0.14cdA−1 respectively.