Room-Temperature Columnar Liquid Crystals as Efficient Pure Deep-Blue Emitters in Organic Light-Emitting Diodes with an External Quantum Efficiency of 4.0%

Abstract

A novel design of aggregation-induced emission (AIE) active columnar (Col) luminomesogens is reported, and they are demonstrated to act as highly efficient deep-blue emitters in organic light-emitting diodes (OLEDs). All derivatives exhibit Col liquid crystalline (LC) behavior at room temperature over a wide temperature range and desirable alignment properties, which is very important in using them as materials for organic electronic devices. These new AIE active luminomesogens were found to act as highly efficient emitters in OLEDs and unveiled a maximum external quantum efficiency of 4.0% for the first time in Col LCs with Commission International de l’E’clairage coordinates of (0.17, 0.07), which closely matches the National Television System Committee (NTSC) standard, corresponding to pure deep blue color. The detailed supramolecular assembly of the compounds has been characterized by modeling in the mesophase derived from small- and wide-angle X-ray scattering results.

2D Ruddlesden–Popper Perovskite Nanoplate Based Deep‐Blue Light‐Emitting Diodes for Light Communication

“…The average EQE of the devices is 0.25% with a standard deviation of ≈0.07% over 20 devices. Note that the performance of our devices is still lower than those of a few organic deep‐blue LEDs, which is possibly attributed to the intrinsically low charge carrier mobility of the 2D perovskites . It is expected that the device performance could be further improved by using suitable incorporating organic ammonium cations that have higher charge carrier mobility than that of PEA in the 2D perovskites, while maintaining the Ruddlesden–Popper‐phase perovskite structure .…”

“…Deep‐blue (400–420 nm) light‐emitting diodes (LEDs) have attracted considerable attention because of their wide applications in the fields of fluorescence‐based chemical and biological sensors, display technology, and light fidelity (Li‐Fi) . Commercially available deep‐blue LEDs are fabricated using high‐quality, direct, and broad bandgap inorganic semiconductors, such as indium gallium nitride (GaInN) and gallium nitride (GaN).…”

Novel Zinc Complex with an Ethylenediamine Schiff Base for High-Luminance Blue Fluorescent OLED Applications

“…64 ), while the doped device B demonstrates an extraordinary brightness about 17 cd/m 2 comparing with other modern blue OLEDs. [10][11][12][13][14][15][16][17][65][66][67] A possible way to improve the lighting parameters of the fabricated devices could be: 1) manipulating with the dopant concentration and host matrix material to reduce the excimer emission that should significantly decrease the value of the y coordinate on the CIE plot so that a deep blue narrow emission can be achieved to satisfy BT.2020 standard; 68 2) manipulating with the thickness of functional layers to decrease the current density parameter and thus to enhance the current and power efficiency.…”

Seeing the Unseen: The Role of Liquid Crystals in Gas‐Sensing Technologies

“…Additionally, they respond rather easily to external stimuli, such as electrical and magnetic fields, mechanical shear, pressure, surface effects, light, temperature, and chemical analytes with a change in their configuration that can be traced using a variety of characterization techniques. Due to this responsive and dynamic nature, the exploitation of LCs covers a wide range of discipline fields and applications in line with the current technological and societal needs, such as flat panel displays, [ 3 ] adaptive lenses and filters, [ 4,5 ] energy, [ 6–8 ] photonics, [ 9,10 ] biomedicine, [ 11,12 ] and design and architecture. [ 13,14 ]…”