CC BY-NC-ND 4.0 · Organic Materials 2020; 02(01): 011-019
DOI: 10.1055/s-0039-3402513
Original Article
The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/). (2020) The Author(s).

Fluorine-Substituted Phenanthro[9,10-d]imidazole Derivatives with Optimized Charge-Transfer Characteristics for Efficient Deep-Blue Emitters

a   State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
,
Ning Xie
a   State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
,
Yincai Xu
a   State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
,
a   State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
,
a   State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
,
a   State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
› Author Affiliations
Funding Information This work was supported by the National Natural Science Foundation of China (21935005 and 51803069) and Program for JLU Science and Technology Innovative Research Team (2019TD-33).
Further Information

Publication History

Received: 15 October 2019

Accepted after revision: 19 November 2019

Publication Date:
23 January 2020 (online)


Abstract

The development of high-efficiency deep-blue emitters is of great importance for full-color organic light-emitting diodes (OLEDs). In this contribution, three difluorine-substituted phenanthro[9,10-d]imidazole derivatives with optimized charge-transfer character and deep-blue emission have been developed. It is demonstrated that the fluorine substitution can facilitate the “state mixing” of singlet and triplet excitons, which increases the utilization of triplet excitons. The fluorine substitution also brings more intermolecular interactions which have influence on the molecular packing pattern of the solid states, ultimately impacting their carrier mobilities. Through fine-tuning of molecular structures, 4'-(1-(3,5-difluorophenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)-N,N-diphenyl-[1,1'-biphenyl]-4-amine (2FPPIDPA) realized a high exciton utilization ratio with Commission Internationale de L'Eclairage (CIE) coordinates of (0.156, 0.046), and 4'-(1-(3,5-difluorophenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)-N,N-diphenyl-[1,1'-biphenyl]-4-amine (2FPPIDPA) achieved an external quantum efficiency of 8.47% with CIE coordinates of (0.152, 0.083) in multilayer OLEDs. Due to their good hole-transport abilities, double-layer OLEDs without the hole-transport layer showed performances comparable or even superior to the multilayer ones.

Supporting Information

Supporting information for this article is available online at: https://doi.org/10.1055/s-0039-3402513.


Supporting Information

Primary Data