Nanomaterials (Jan 2024)

Bicarbazole-Benzophenone-Based Twisted Donor-Acceptor-Donor Derivatives as Blue Emitters for Highly Efficient Fluorescent Organic Light-Emitting Diodes

  • Dovydas Blazevicius,
  • Iram Siddiqui,
  • Prakalp Gautam,
  • Gintare Krucaite,
  • Daiva Tavgeniene,
  • Mangey Ram Nagar,
  • Krishan Kumar,
  • Subrata Banik,
  • Jwo-Huei Jou,
  • Saulius Grigalevicius

DOI
https://doi.org/10.3390/nano14020146
Journal volume & issue
Vol. 14, no. 2
p. 146

Abstract

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This paper delves into the development of a group of twisted donor-acceptor-donor (D-A-D) derivatives incorporating bicarbazole as electron donor and benzophenone as electron acceptor for potential use as blue emitters in OLEDs. The derivatives were synthesized in a reaction of 4,4′-difluorobenzophenone with various 9-alkyl-9′H-3,3′-bicarbazoles. The materials, namely, DB14, DB23, and DB29, were designed with different alkyl side chains to enhance their solubility and film-forming properties of layers formed using the spin-coating from solution method. The new materials demonstrate high thermal stabilities with decomposition temperatures >383 °C, glass transition temperatures in the range of 95–145 °C, high blue photoluminescence quantum yields (>52%), and short decay times, which range in nanoseconds. Due to their characteristics, the derivatives were used as blue emitters in OLED devices. Some of the OLEDs incorporating the DB23 emitter demonstrated a high external quantum efficiency (EQEmax) of 5.3%, which is very similar to the theoretical limit of the first-generation devices.

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