All solution-processed, high performance hybrid light emitting transistors (HLETs) are realized. Using a novel combination of device architecture and materials a bilayer device comprised of an inorganic and organic semiconducting layer is fabricated and the optoelectronic properties are presented.

Area emission is realized in all-solution-processed hybrid light-emitting transistors (HLETs). A new HLET design is presented with increased aperture ratio, and optical and electrical characteristics are shown.

The rapid development of charge transporting and light-emitting organic materials in the last decades has advanced device performance, highlighting the high potential of light-emitting transistors (LETs). Demonstrated for the first time over 15 years ago, LETs have transformed from an optoelectronic curiosity to a serious competitor in the race for cheaper and more efficient displays, also showing promise for injection lasers. Thus, what is an LET, how does it work, and what are the current challenges for its integration into mainstream technologies? Herein, some light is shed on these questions. This work also provides the fundamental working principle of LETs, materials that have been used, and device physics and architectures involved in the progression of LET technology. The state-of-the-art development of LETs is also explored as prospect avenues for the future of research and applications in this area.

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COMMUNICATIONEQEs by a factor of 20 at higher brightness compared to the control planar tri-layer LEFETs. More recently, similar heterostructure LEFETs were employed to give an increased and welldefi ned light-emitting area for display applications. However, these devices still suffered from poor carrier mobility and the light-emitting area is heavily dependent on applied gate voltage. Despite the tremendous progress and technological potential of all-organic heterostructure LEFETs, the carrier mobility values achieved to date remain low (<1 cm 2 V −1 s −1 ) while the lightemitting area is either too narrow or nonuniform and strongly dependent on the biasing conditions. Finally, the high voltage often required to drive these devices (≈100 V) dramatically increases the overall power consumption, which renders the technology unsuitable for display applications.To improve the charge carrier mobility, hybrid nonplanar LEFET architectures employing different charge-transporting inorganic semiconductors such as CdS and metal oxides (e.g., ZnO, ZTO) have been developed to offer a much higher mobility of up to 19 cm 2 V −1 s −1 and a high channel current ON/OFF ratio (>10 6 ) with a lower EQE (typically ≈0.01%). [21][22][23][24][25][26] Although respectable electrical device performance has been demonstrated, it has remained challenging to achieve a high EQE and brightness simultaneously, especially at lower operating voltages (<25 V). Furthermore, the major drawbacks of reported hybrid LEFETs are: i) very high processing temperatures (typically >500 °C) necessary for sintering metal oxides, which are incompatible with processing on plastic substrates; and ii) edge light emission zone leading to low (2.5%) aperture ratios (defi ned as the ratio of light-emitting area over total device area). Such narrow emission zone restricted to the edge of the emitting electrode in the reported hybrid heterostructure LEFETs is not suitable for application in display technologies. [6][7][8]17,[21][22][23][24][25] To overcome this issue, we recently showed that incorporation of the solution-processed interlayer-ethoxylated polyethylenimine (PEIE) can modify the surface energy of the inorganic charge transporting layer resulting in enhanced carrier injection and uniform light emission across the electrode area. [ 26 ] However, the EQE value obtained from these devices remained low (10 −2 %-10 −1 %), and the operating voltages high (100 V). Furthermore, the processing temperature required for the deposition of the inorganic layer was high (500 °C) and incompatible with inexpensive, temperature-sensitive substrate materials.Here, we report hybrid LEFETs fabricated with low temperature and solution-processed organic and inorganic metal oxide Organic light-emitting fi eld effect transistors (LEFETs) evolved from organic fi eld effect transistors (OFETs) and organic lightemitting diodes (OLEDs) into a new multifunctional optoelectronic device. LEFETs combine the switching functionality of an FET with light emission of an OLED in a transistor...

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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