Recent Progress in High‐Efficiency Blue‐Light‐Emitting Materials for Organic Light‐Emitting Diodes

Abstract

Organic light-emitting diodes (OLEDs) are increasingly used in displays replacing traditional flat panel displays; e.g., liquid crystal displays. Especially, the paradigm shifts in displays from rigid to flexible types accelerated the market change from liquid crystal displays to OLEDs. However, some critical issues must be resolved for expansion of OLED use, of which blue device performance is one of the most important. Therefore, recent OLED material development has focused on the design, synthesis and application of highefficiency and long-life blue emitters. Well-known blue fluorescent emitters have been modified to improve their efficiency and lifetime, and blue phosphorescent emitters are being investigated to overcome the lifetime issue. Recently, thermally activated delayed fluorescent emitters have received attention due to the potential of high-efficiency and long-living emitters. Therefore, it is timely to review the recent progress and future prospects of high-efficiency blue emitters. In this feature article, we summarize recent developments in blue fluorescent, phosphorescent and thermally activated delayed fluorescent emitters, and suggest key issues for each emitter and future development strategies.

Neural network modeling and simulation of the synthesis of CuInS2/ZnS quantum dots

“…They have promising applications in solar cell, light emitting diodes (LEDs), sensors, fluorescent probes, biolabeling, and anticounterfeiting . For example, QDs‐based LEDs, so called QLEDs, exhibit longer photoluminescence (PL) lifetime and higher thermal stability than organic light emitting diodes and, therefore, have been applied in the latest generation of displays . However, currently used QLEDs, for example, in flat‐screen televisions apply CdSe‐based QDs.…”

Development of Materials for Blue Organic Light Emitting Devices

“…The device efficiency has gone significantly up. [1,[9][10][11] For example, we recently reported a TADF OLED with above 36 % external quantum efficiency (EQE) based on an emitter composed of acridine-based donor and triazine-based acceptor. [12] The third generation OLED (TADF OLEDs) appears to be promising alternatives for the more expensive PhOLEDs.…”

“…Attempts to increase the device efficiency by using blue phosphorescent materials instead of the fluorescent materials weren't too successful as the successive devices lacked appreciable lifetime for practical applications though the h int was significantly improved. [9] But, our group recently developed pyrimidine-based iridium complex with both high efficiency and long durability, and thus, circumvented the long-standing challenge of low device lifetimes in blue phosphorescent emitters. [15] This result may keep the momentum for searching new blue phosphors with reliable features to fulfill the demands of device efficiency and durability.…”

High Performance Thermally Activated Delayed Fluorescence Sensitized Organic Light‐Emitting Diodes

“…To break this contradiction, several stratagems have been proposed and summarized in recent reviews. [9][10][11][12][13][14][15] By using these strategies, recently reported green TADF OLEDs have realized maximum EQE of 37.8 %, even higher than these of state-of-the-art green PhOLEDs. [16] Moreover, maximum EQEs of sky-blue and orange TADF OLEDs could also achieve 36.7 % and 29.2 %, respectively.…”