Highly efficient deep-blue organic electroluminescent devices (CIEy ≈ 0.08) doped with fluorinated 9,9′-bianthracene derivatives (fluorophores)

Abstract

A series of new fluorinated 9,9 0 -bianthracene derivatives (BAnFs) have been designed and synthesized to serve as deep-blue dopants in organic electroluminescent (EL) devices. With the different substitution patterns of the electron-withdrawing groups, such as F and CF 3 , the photophysical properties, the energy levels and thermal stability of these BAnFs are tuned, which are supported by a density functional study of their geometry and electronic structure. In the thin film state, the fluorescent emissions of the BAnFs are fine-tuned from 448 to 439 nm, with varied fluorinated phenyl rings attached to the 9,9 0 -bianthracene core. All the BAnFs show a considerable thermal stability, which have high T g values, above 150 C. A pure blue emission at the Commission Internationale de l' Éclairage (CIE) coordinates (0.156, 0.083), has been achieved using the host 4,4 0 -bis(N-carbazolyl)biphenyl (CBP) doped with 10,10 0 -bis(3,5-bis(trifluoromethyl)phenyl)-9,9 0 -bianthracene (BAn-(3,5)-CF 3 ). The maximum current efficiency and power efficiency of the BAn-(3,5)-CF 3 -doped device are 3.05 cd A À1 and 2.62 lm W À1 , corresponding to 5.02% of the maximum external quantum efficiency. The synthesized new fluorinated 9,9 0 -bianthracene derivatives show potential applications as highly efficient pure blue emitters for organic light emitting devices.

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

“…However, the LUMO of ICz‐PPI are mainly located on ICz group that attached to C2‐positions of PI, manifesting that there is a small overlap between HOMO and LUMO in ICz‐PPI . It is believed that a small part overlapping between the HOMO and LUMO, result in an effective electronic communication between the indolocarbazole and phenanthroimidazole unit . In fact, it would be conductive to balance the charge transfer and promote highly efficient luminescence as the emitter in OLED.…”

“…It is believed that a small part overlapping between the HOMO and LUMO, result in an effective electronic communication between the indolocarbazole and phenanthroimidazole unit. [33] In fact, it would be conductive to balance the charge transfer and promote highly efficient luminescence as the emitter in OLED. On the other hand, it could also facilitate to promote the charge transfer process upon excitation.…”

High Efficiency Fluorescent Electroluminescence with Extremely Low Efficiency Roll‐Off Generated by a Donor–Bianthracene–Acceptor Structure: Utilizing Perpendicular Twisted Intramolecular Charge Transfer Excited State

“…We use BA with TICT characteristics as the central core, and add D or A on each side of BA core. Herein we introduce two D–BA–A structure molecules 4‐[10′‐(4‐methoxy‐phenyl)‐[9,9′]bianthracenyl‐10‐yl]‐benzonitrile (NCBAOMe) and 9‐(4‐{10′‐[4‐(4,6‐diphenyl‐[1,3,5]triazin‐2‐yl)‐phenyl]‐[9,9′]bianthracenyl‐10‐yl}‐phenyl)‐9H‐carbazole (TrBACa).…”

“…In this paper, we demonstrate a new strategy to achieve both high η r of 64.82% and extremely low external quantum efficiency (EQE) roll‐off of 0.9% from peak values to those even at a high current density of 100 mA cm −2 by spin mixing of high‐lying perpendicular twisted intramolecular charge transfer (TICT) singlet and triplet excited states. We select 9,9′‐bianthracene (BA) moiety as the central core, which have almost perpendicular electronic structure, TICT characteristics, and intense fluorescence emission of LE states, based on our investigation of fluorinated BA derivatives before, and report two novel molecules with highly twisted D–BA–A structure by modifying BA with D and A on both sides, respectively. In the process of electron injection, high‐lying TICT intermediate excited states with smaller singlet–triplet energy splitting due to the decreased electronic coupling between D and A by the almost perpendicular BA core would cause more efficient hot exciton RISC channel.…”

Synthesis and Electroluminescence Properties of 3-(Trifluoromethyl)phenyl-Substituted 9,10-Diarylanthracene Derivatives for Blue Organic Light-Emitting Diodes

“…In addition, the introduction of a bulky 3-(trifluoromethyl)phenyl) unit into the anthracene core can efficiently prevent the intermolecular aggregations and reduce self-quenching behaviors. Although several fluorinated DAA derivatives at the 9,10-position of the anthracene groups as noticeable blue host materials have been reported [40,41], the example of 2-fluorinated DAA compounds has never been studied.…”