Red phosphorescent trilayer organic light-emitting field-effect transistors with a wide recombination zone

Chang, Jyh‐Yeong; Chen, Wei Ren; Lai, Yi Chien; Chien, Fan Ching

doi:10.7567/jjap.55.020304

Cited by 9 publications

(8 citation statements)

References 16 publications

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“…[12,[14][15][16][35][36][37] This limited efficiency roll-off is confirmed in Figure 4b that represents EQE averaged over the whole linear region as a function of current density. [12,[14][15][16][35][36][37] This limited efficiency roll-off is confirmed in Figure 4b that represents EQE averaged over the whole linear region as a function of current density.…”

Section: Wwwadvelectronicmatdesupporting

confidence: 58%

“…At ( V GSn , V GSp ) = (60, −22) V, a tenfold increase in luminance is obtained (2190 cd m −2 ) under a current density of 28 mA cm −2 . The current efficiency remains at a respectable 7.8 Cd A −1 and the EQE at 5.7%, barely lower than the maximum EQE and substantially higher than the efficiency of previously reported high‐performance red‐emitting OLETs . This limited efficiency roll‐off is confirmed in Figure b that represents EQE averaged over the whole linear region as a function of current density.…”

Section: The Literature Benchmark Table Compares Select Olet Work Basupporting

confidence: 58%

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Overlapping‐Gate Organic Light‐Emitting Transistors

Lee

Genoe

et al. 2018

Adv Elect Materials

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The most common OLET architecture relies on a single gate (SG-OLETs) to control the transport of both electrons and holes toward the radiative recombination zone. As a consequence, hole-electron current balance in SG-OLETs can only be achieved at an intermediate gate bias. When driven at high currents, the current imbalance in SG-OLETs usually results in inefficient light emission very close to, or even under the source electrode of the transport layer with the lowest conductivity. [1,[11][12][13][14][15][16] In addition, the emission zone can unpredictably switch from one contact to the other upon small bias changes. [17][18][19][20][21][22] For these reasons, considerable roll-off is observed at increasing bias. Only a few fluorescent SG-OLETs have achieved external quantum efficiency (EQE) over 5% [12,13] and the peak EQE is only obtained at very low current and luminance. [12][13][14]17,[20][21][22] A variation around the SG-OLET topology is the vertical OLET where hole and electron sources are stacked above the gate whose main objective is to modulate charge injection from one of the sources into the device. [23][24][25][26] This compact topology intimately integrates the actions of switching and light emission, which is particularly suited for display applications. But the vertical OLET also suffers from roll-off when driven at high current densities. For all SG-OLET topologies, maintaining the high efficiency at high current level with balanced hole-electron currents remains a major challenge.Dual gate OLETs with two adjacent gates formed by the direct patterning of a single metallic film ("split-gate") have been proposed to decouple electron and hole currents and simultaneously achieve balanced transport at high current density. Unfortunately, the large spatial gap between the gates, more than 1 µm, forms a highly resistive active region which limits the current, resulting in low luminance (below 1000 cd m −2 ) and low EQE (1.3%). [27][28][29][30] Also "opposinggate" dual-gate OLETs have been proposed, where the active organic layer stack is vertically sandwiched between two insulators and two gates that each accumulate one species of charge carriers at either side of the active layer. But the vertical electric field between the gates strongly opposes charge injection and recombination into the central emissive layer, resulting in poor light emission. [31] In this work, we propose a novel dual-gate architecture, the overlapping-gates OLET (OG-OLET), that overcomes the shortcomings of previous OLET topologies. We show how this new device combines the important features of balanced electronhole transport up to high current density and light emission far A light-emitting transistor in which two gates, separated by an insulator, partially overlap in the center of the device is proposed. By accumulating charge carriers in dedicated transport layers, each gate independently controls charge injection into the emissive layer sandwiched between the transport layers. This structure combines the advantages of pinned...

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Section: Wwwadvelectronicmatdesupporting

confidence: 58%

Section: The Literature Benchmark Table Compares Select Olet Work Basupporting

confidence: 58%

Overlapping‐Gate Organic Light‐Emitting Transistors

Lee

Genoe

et al. 2018

Adv Elect Materials

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“…The device performance exceeds previously reported organic LEFETs based on phosphorescent emitters. [29][30][31][32] Figure 1. Heteroleptic complexes bearing an n-hexyloxyphenyllepidine cyclometalated ligand and two different co-ligands: i.e., 1 with a picolinato (pic) co-ligand and 2 with an acetylacetonato (acac) co-ligand.…”

Section: Introductionmentioning

confidence: 99%

Orange‐Red‐Light‐Emitting Field‐Effect Transistors Based on Phosphorescent Pt(II) Complexes with Area Emission

Wawrzinek

Muhieddine

Ullah

et al. 2016

Advanced Optical Materials

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Two new heteroleptic Pt(II) complexes bearing an n-hexyloxy substituted phenyllepidine-based ligand and either a picolinate (pic) or acetlyacetonate (acac) co-ligand were synthesised for use in organic light-emitting field-effect transistors (LEFETs). Both compounds were obtained in This article is protected by copyright. All rights reserved. 2 good yields via a short and straightforward synthetic route. It was found that while both Pt(II) complexes showed good chemical stability and solubility, the co-ligand affected the photoluminescence quantum yield and crystal packing of the complexes. Although aggregate induced phosphorescence enhancement was not observed it was found that high concentrations of the emitters in a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine host led to improved charge injection in hybrid LEFETs. LEFETs with area emission, high ON/OFF ratios (>10 6 ) and mobilities (≈1.3 cm 2 /Vs), and external quantum efficiencies of up to 0.08% at the high brightness of ≈750 cd/m 2 were demonstrated.

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“…Chang et al achieved a maximum RZ W of 60-70 µm across the transistor channel by energy level matching strategy between the charge transport carriers (DNTT, DFH-4T) and emitter (Bebq 2 :Ir(piq) 3 ) in a trilayer OLET device architecture. [91] These results reveal that several parameters such as balanced hole/ electron mobility and favorable energy levels play a crucial role in widening the RZ W in a multilayer architecture.…”

Section: Device Engineering Tacticsmentioning

confidence: 84%

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

Ganesan

Tsao

Gao

2021

Adv Funct Materials

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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.

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Red phosphorescent trilayer organic light-emitting field-effect transistors with a wide recombination zone

Cited by 9 publications

References 16 publications

Overlapping‐Gate Organic Light‐Emitting Transistors

Overlapping‐Gate Organic Light‐Emitting Transistors

Orange‐Red‐Light‐Emitting Field‐Effect Transistors Based on Phosphorescent Pt(II) Complexes with Area Emission

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

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