En Route to Wide Area Emitting Organic Light‐Emitting Transistors for Intrinsic Drive‐Integrated Display Applications: A Comprehensive Review

Abstract

Organic light-emitting transistors (OLET) evolved from the fusion of the switching functionality of field-effect transistors (FET) with the light-emitting characteristics of organic light-emitting diode (OLED) that can simplify the active-matrix pixel device architecture and hence offer a promising pathway for future flat panel and flexible display technology. This review systematically analyzes the key device/molecular engineering tactics that assist in improving the electrode edge narrow emission to wide-area emission for display applications via three different topics, that is, narrow to wide-area emission, vertical architecture, and impact of high-κ dielectric on the device performance. Source-drain electrode engineering such as symmetric/asymmetric, planar/ non-planar arrangement, semitransparent nature, multilayer approach comprising charge transport, and work function modification layers enable widening the emission zone. Vertical OLET architecture offers short channel lengths with a high aperture ratio, pixel type area emission, and stable lightemitting area. Transistors utilizing high-κ dielectric materials have assisted in lowering the operating voltage, enhancing luminance and air stability. The promising development in achieving wide-area emission provides a solid basis for constructing OLET research toward display applications; however, it relies on developing highly luminescent and fast charge transporting materials, suitable semitransparent source/drain electrodes, high-κ -dielectrics, and device architectural engineering.

Impact of Electron-Donating Groups on Attaining Dual-Emitting Imidazole-Based Donor–Acceptor Materials

“…As shown in the above-discussed reports, the enhanced contribution of either the LE- or CT-based SW or LW emission was influenced by the polarity of the solvent, varying the substituent groups, and the linkage position. Therefore, it will be advantageous to develop materials that exhibit concurrent dual emission (SW + LW) covering the different visible regions, which will aid in the future development of panchromatic visible light-emitting materials. − In this context, the present work focuses on attaining the combined SW- and LW-based dual-emission characteristics of the imidazole derivatives. For this purpose, the benzonitrile fragment and phenyl acetonitrile are introduced via C-P1 and N-P2, respectively, into the imidazole core to form ImDCN as a common intermediate (Scheme ).…”

Interplay between Charge Injection, Electron Transport, and Quantum Efficiency in Ambipolar Trilayer Organic Light‐Emitting Transistors

“…Thus, on one side, the use of a bphen interlayer expanded the OLET emissive area and the geometrical fill factor, as it is desired for pixel design in display applications. [43] On the other side, the implementation of a vertical electron injecting layer, that is typical of OLED structures, in a bidimensional OLET device further extends the library of materials that can be implemented in OLETs.…”

Buried‐Contact Organic Field‐Effect Transistor: The Way of Alleviating Drawbacks from Interfacial Charge Transfer

“…[2,[20][21][22][23][24] One of the fundamental reasons for the high R C is the Schottky barrier that arises owing to the energy level mismatch between the OSC and metal S/D. In previous studies, the energy-level mismatch at the Schottky barrier interface was controlled by applying various strategies, including introducing a doped interface, [25,26] inserting a metal oxide interfacial layer, [27,28] and forming selfassembled monolayers. [29][30][31][32] However, recent studies on the origin of R C have revealed that R C is composed of the interfacial contact resistance (R C,int ) and access contact resistance (R C,acc ), and R C,acc has a greater contribution to R C than R C,int [33][34][35] R C,int arises from to the substantial energy-level mismatch between the OSC and S/D, corresponding to the Schottky barrier.…”