Blue-Light-Emitting Bis(diarylamino)stilbene Derivatives: Synthesis, Photophysical Properties, and Highly Efficient OLEDs

Abstract

New electroluminescent materials, 4,4′-bis(2-naphthyl-4-tert-butylphenylamino)stilbene (1), 4,4′-bis(4-tert-butylphenyl-3,5-di-tert-butylphenylamino)stilbene (2), and 4,4′-bis(di-4-tert-butylphenylamino)stilbene (3) were synthesized and characterized. To evaluate the electroluminescent properties of these compounds, multilayered OLED devices 1-3 were designed. By employing blue dopant 1 into a multilayer device, it was possible to achieve a maximum luminance of 8861 cd m⁻² at 12.0 V, a luminous efficiency of 6.82 cd A⁻¹ at 20 mA cm⁻², a power efficiency of 2.72 lm W⁻¹ at 20 mA cm⁻², and CIE _x,y coordinates of (x = 0.158,y = 0.187) at 10.0 V. These results demonstrated the superiority of these bis(diarylamino)stilbene derivatives in organic light-emitting devices.

Keywords:

• Bis(diarylamino)stilbene
• blue fluorescent materials
• Buchwald-Hartwig cross-coupling reaction
• organic light-emitting diode

Acknowledgments

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (20090073679).

Notes

[a,b] Maximum absorption and emission wavelength, measured in CH₂Cl₂ solution. [c] Obtained from AC-2 and the intersection of the absorption and photoluminescence spectra. [d] Using BDAVBi as a standard; λ_ex = 360 nm (Φ = 0.86 in CH₂Cl₂).

[a, b] The maximum current density and luminance, [c] Maximum values, [d] At 20 mA/cm², [e] Commission Internationale d'Énclairage (CIE) coordinates at 10.0 V.