Highly Efficient Circularly Polarized Electroluminescence from Aggregation‐Induced Emission Luminogens with Amplified Chirality and Delayed Fluorescence

Abstract

Development of highly efficient circularly polarized organic light‐emitting diodes (CPOLEDs) has gained increasing interest as they show improved luminous efficiency and high contract 3D images in OLED displays. In this work, a series of binaphthalene‐containing luminogenic enantiomers with aggregation‐induced emission (AIE) and delayed fluorescence properties is designed and synthesized. These molecules can emit from green to red light depending on the solvent polarity due to the twisted intramolecular charge transfer effect. However, their solid powders show bright light emissions, demonstrating a phenomenon of AIE. All the molecules exhibit Cotton effects and circularly polarized luminescence in toluene solution and films. Multilayer CPOLEDs using the doped and neat films of the molecules as emitting layers are fabricated, which exhibit high external quantum efficiency of up to 9.3% and 3.5% and electroluminescence dissymmetry factor (gEL) of up to +0.026/−0.021 and +0.06/−0.06, respectively. Compared with doped CPOLEDs, the nondoped ones show higher gEL and much smaller current efficiency roll‐off due to the stronger AIE effect. By altering the donor unit, the electroluminescence maximum of the doped film can vary from 493 to 571 nm. As far as it is known, this is the first example of efficient CPOLEDs based on small chiral organic molecules.

Chiral Perovskites: Promising Materials toward Next‐Generation Optoelectronics

“…CPL spectroscopy explicitly measures the differential spontaneous emission of left and right circularly polarized radiations by a luminescent system, and thereby served as another key technique to act as chiral probes . Luminous materials capable of CPL have already been preferably applied in optical field, especially in light‐emitting diodes (LEDs), mainly because of the high luminous efficiency and the high resolution that CPL can give raise to . In view of the successful employment of perovskites as emissive optical materials and in combination with outstanding CPL attributes of chiral molecules, chiral perovskites are highly desirable for CPL‐active optical materials.…”

Stimuli‐Responsive Properties of Aggregation‐Induced‐Emission Compounds Containing a 9,10‐Distyrylanthracene Moiety

“…This pH-responsive behavior is attributed to the protonation of the triphenylamino group,w hich effectivelye liminates the intrinsic intramolecular charge-transfer of donor-acceptor molecules. [1,31] However,s uch pH-induced fluorescences witching could not be reproduced by using the following acids:H Cl, HNO 3 ,H COOH, CH 3…”

“…The product was further purified by recrystallization (hexane/dichloromethane) for property measurements. 1…”

“…Functional materials that changet heir properties in response to as ingle stimulus or multiple stimuli are called smart materials. [1] Piezochromism is ap henomenon in whicht he luminescence properties of materials changew ith mechanical force, for whicht he presence of more than two different pressuredependent stable or metastable states is essential. [2][3][4] Piezochromic luminescent materials have received considerable interest in recent years in view of their potentiala pplicationsi n sensors,m emoryc hips, camouflage, optoelectronic devices, and so forth.…”

“…AIE-based piezochromic materials with more than two different pressure-dependents table or metastable states have rarely been reported. [1,16,17] To obtain multicolored switching luminophores with enhanced emission in the solid state, [18][19][20][21][22][23] we designed and synthesized 9,10-distyrylanthracene derivatives JX01 and JX02 (Scheme 1) and explored their AIE and stimuli-responsive properties. The planar 3,6-dimethoxycarbazole group was introduced into JX02 to adjust the relatedp roperties and for comparison.…”