Novel D-A-D Fluorescent Dyes Based on 9-(p-Tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a Donor Unit for Solution-Processed Organic Light-Emitting-Diodes.

Vladislav M Korshunov,Nikita S Gudim,Andrey A Vashchenko,Maxim S Mikhailov,Lyudmila V Mikhalchenko,Ilya V Taydakov,Timofey N Chmovzh,Oleg A Rakitin

doi:10.3390/molecules26102872

Abstract

New fluorescent D-A-D dyes containing 9-(p-tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a donor unit and 2,1,3-benzochalcogenadiazoles as an electron-withdrawing group were synthesized. The photoluminescent and electroluminescent properties of novel dyes for fluorescent OLED application were investigated. It was demonstrated that the replacement of lightweight heteroatoms by heavier ones enables the fine tuning of the maximum emission without significantly reducing the luminescence quantum yield. The maximum quantum yield value of 62.6% for derivatives based on 2,1,3-benzoxadiazole (1a) in cyclohexane was achieved. Two devices with the architecture of glass/ITO/PEDOT-PSS/poly-TPD/EML/TPBi/LiF/Al (EML = emitting layer) were fabricated to check the suitability of the synthesized compounds as a single active emission layer in OLED. These OLEDs exhibited clear red electroluminescence of the dyes with the maximum current efficiency of 0.85 Cd/A.

Highlights

In recent decades, there has been an active search and study of new donor-acceptor (D-A) organic compounds
There has been an active search and study of new donor-acceptor (D-A) organic compounds. This interest is due to a wide range of practical problems associated with the development of electronic devices, such as organic light-emitting diodes (OLED) [1,2,3,4], dye-synthesized solar cells which convert solar energy into electrical energy (DSSC) [5,6], and electronic switches [7,8]
Particular attention is paid to structures of the D-A-D type, since the introduction of an additional donor improves the properties of the intramolecular charge transfer (ICT) mechanism [10,11]

Summary

Introduction

There has been an active search and study of new donor-acceptor (D-A) organic compounds. This interest is due to a wide range of practical problems associated with the development of electronic devices, such as organic light-emitting diodes (OLED) [1,2,3,4], dye-synthesized solar cells which convert solar energy into electrical energy (DSSC) [5,6], and electronic switches [7,8]. It is possible to purposefully synthesize materials capable of luminescence in the entire visible range of the spectrum, as well as in the near infrared part of the spectrum

Methods

Results

Conclusion