High‐Efficiency Single‐Component Organic Light‐Emitting Transistors

Construction of high‐performance organic light‐emitting transistors (OLETs) remains challenging due to the limited desired organic semiconductor materials. Here, two superior high mobility emissive organic semiconductors, 2,6‐diphenylanthracene (DPA) and 2,6‐di(2‐naphthyl) anthracene (dNaAnt), are introduced into the construction of OLETs. By optimizing the device geometry for balanced ambipolar efficient charge transport and using high‐quality DPA and dNaAnt single crystals as active layers, high‐efficiency single‐component OLETs are successfully fabricated, with the demonstration of strong and spatially controlled light emission within both p‐ and n‐ conducting channels and output of high external quantum efficiency (EQE). The obtained EQE values in current devices are approaching 1.61% for DPA‐OLETs and 1.75% for dNaAnt‐based OLETs, respectively, which are the highest EQE values for single‐component OLETs in the common device configuration reported so far. Moreover, high brightnesses of 1210 and 3180 cd m^?2 with current densities up to 1.3 and 8.4 kA cm^?2 are also achieved for DPA‐ and dNaAnt‐based OLETs, respectively. These results demonstrate the great potential applications of high mobility emissive organic semiconductors for next‐generation rapid development of high‐performance single‐component OLETs and their related organic integrated electro‐optical devices.     

Organic Light‐Emitting Transistors: Materials,Device Configurations,and Operations

Organic light‐emitting transistors (OLETs) represent an emerging class of organic optoelectronic devices, wherein the electrical switching capability of organic field‐effect transistors (OFETs) and the light‐generation capability of organic light‐emitting diodes (OLEDs) are inherently incorporated in a single device. In contrast to conventional OFETs and OLEDs, the planar device geometry and the versatile multifunctional nature of OLETs not only endow them with numerous technological opportunities in the frontier fields of highly integrated organic electronics, but also render them ideal scientific scaffolds to address the fundamental physical events of organic semiconductors and devices. This review article summarizes the recent advancements on OLETs in light of materials, device configurations, operation conditions, etc. Diverse state‐of‐the‐art protocols, including bulk heterojunction, layered heterojunction and laterally arranged heterojunction structures, as well as asymmetric source‐drain electrodes, and innovative dielectric layers, which have been developed for the construction of qualified OLETs and for shedding new and deep light on the working principles of OLETs, are highlighted by addressing representative paradigms. This review intends to provide readers with a deeper understanding of the design of future OLETs.     

Recent Developments in Top‐Emitting Organic Light‐Emitting Diodes

Organic light‐emitting diodes (OLEDs) have rapidly progressed in recent years due to their unique characteristics and potential applications in flat panel displays. Significant advancements in top‐emitting OLEDs have driven the development of large‐size screens and microdisplays with high resolution and large aperture ratio. After a brief introduction to the architecture and types of top‐emitting OLEDs, the microcavity theory typically used in top‐emitting OLEDs is described in detail here. Then, methods for producing and understanding monochromatic (red, green, and blue) and white top‐emitting OLEDs are summarized and discussed. Finally, the status of display development based on top‐emitting OLEDs is briefly addressed.     

Organic Materials for Deep Blue Phosphorescent Organic Light‐Emitting Diodes

Recently, great progress has been made in the device performance of deep blue phosphorescent organic light‐emitting diodes (PHOLEDs) by developing high triplet energy charge‐transport materials, high triplet energy host and deep blue emitting phosphorescent dopant materials. A high quantum efficiency of over 25% and a high power efficiency of over 15 lm/W have already been achieved at 1000 cd m^?2 in the deep blue PHOLEDs with a y color coordinate less than 0.20. In this work, recent developments in organic materials for high efficiency deep blue PHOLEDs are reviewed and a future strategy for the development of high efficiency deep blue PHOLEDs is proposed.