Ambipolar, Single‐Component, Metal–Organic Thin‐Film Transistors with High and Balanced Hole and Electron Mobilities
About: This article is published in Advanced Materials.The article was published on 2008-09-17. It has received 33 citations till now. The article focuses on the topics: Ambipolar diffusion & Thin film.
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TL;DR: In this paper, various classes of molecular structures that may be used as the basis for the synthesis of organic semiconductors that favor electron transport in field effect transistors and related electronic and optoelectronic devices are discussed.
Abstract: This review covers the various classes of molecular structures that may be used as the basis for the synthesis of organic semiconductors that favor electron transport in field-effect transistors and related electronic and optoelectronic devices. The types of compounds include tetracarboxylic diimides, heterocyclic oligomers, fullerenes, and metal complexes. Approaches to polymers are also mentioned. Although brief discussions of transistor operation and applications are included, the emphasis is on the rationale for choosing these structures, and synthetic routes to them. Performance of exemplary compounds in transistors is also discussed.
204 citations
TL;DR: The successful demonstration of high and balanced ambipolar FET properties from nitrogen-containing oligoacenes opens up new opportunities for designing high-performance ambipolar organic semiconductors.
Abstract: We demonstrate a strategy for designing high-performance, ambipolar, acene-based field-effect transistor (FET) materials, which is based on the replacement of C−H moieties by nitrogen atoms in oligoacenes. By using this strategy, two organic semiconductors, 6,13-bis(triisopropylsilylethynyl)anthradipyridine (1) and 8,9,10,11-tetrafluoro-6,13-bis(triisopropylsilylethynyl)-1-azapentacene (3), were synthesized and their FET characteristics studied. Both materials exhibit high and balanced hole and electron mobilities, 1 having μh and μe of 0.11 and 0.15 cm2/V·s and 3 having μh and μe of 0.08 and 0.09 cm2/V·s, respectively. The successful demonstration of high and balanced ambipolar FET properties from nitrogen-containing oligoacenes opens up new opportunities for designing high-performance ambipolar organic semiconductors.
201 citations
TL;DR: In this paper, a π-conjugated coordination nanosheet (CONASH) comprising bis(iminothiolato)nickel moieties, NiIT, was synthesized by a reaction of Ni2+ with 1,3,5-triaminobenzene-2,4,6-trithiol (L) in the presence of ferrocenium ions.
Abstract: A π-conjugated coordination nanosheet (CONASH) comprising bis(iminothiolato)nickel moieties, NiIT, was synthesized by a reaction of Ni2+ with 1,3,5-triaminobenzene-2,4,6-trithiol (L) in the presence of ferrocenium ions. A bulk material, bulk-NiIT, prepared in a homogeneous solution was characterized by XPS, IR, and SEM. A liquid–liquid interfacial reaction using bis(2,4-pentanedionato)nickel(II) in CH2Cl2 and L in H2O afforded a semiconducting nanosheet, nano-NiIT. AFM, SEM, and TEM observation of nano-NiIT revealed the uniform and flat nature of a stacked layer nanosheet. Selected-area electron diffraction (SAED) analysis indicated the formation of a two-dimensional hexagonal crystal structure.
43 citations
TL;DR: In this article, the authors reported ambipolar transport in bottom gold contact, pentacene field effect transistors (FETs) fabricated by spin-coating and thermally converting its precursor on a benzocyclobutene/SiO2 gate dielectric with chemically modified source and drain electrodes.
Abstract: We report ambipolar transport in bottom gold contact, pentacene field-effect transistors (FETs) fabricated by spin-coating and thermally converting its precursor on a benzocyclobutene/SiO2 gate dielectric with chemically modified source and drain electrodes. A wide range of aliphatic and aromatic self-assembled thiolate monolayers were used to derivatize the electrodes and all enhanced electron and hole currents, yet did not affect the observable thin film morphology. Hole and electron mobilities of 0.1–0.5 and 0.05–0.1 cm2/V s are achieved, though the threshold for electron transport was >80 V. These ambipolar FETs are used to demonstrate inverters with gains of up to 94.
32 citations
TL;DR: The complexes M(L(2))(2) showed poor charge transport in a field-effect transistor (FET) device despite the ability to form π-stacking structures, and this provides design insights for metal complexes to be used in conductive thin-film devices.
Abstract: Square planar complexes of the type Ni(L1)2, Ni(L2)2, Cu(L1)2, and Cu(L2)2, where L1H = 2-hydroxy-5-t-octylacetophenone oxime and L2H = 2-hydroxy-5-n-propylacetophenone oxime, have been prepared and characterized by single-crystal X-ray diffraction, cyclic voltammetry, UV/vis spectroscopy, field-effect-transistor measurements, density functional theory (DFT) and time-dependent DFT (TDDFT) calculations, and, in the case of the paramagnetic species, electron paramagnetic resonance (EPR) and magnetic susceptibility. Variation of alkyl groups on the ligand from t-octyl to n-propyl enabled electronic isolation of the complexes in the crystal structures of M(L1)2 contrasting with π-stacking interactions for M(L2)2 (M = Ni, Cu). This was evidenced by a one-dimensional antiferromagnetic chain for Cu(L2)2 but ideal paramagnetic behavior for Cu(L1)2 down to 1.8 K. Despite isostructural single crystal structures for M(L2)2, thin-film X-ray diffraction and scanning electron microscopy (SEM) revealed different morphol...
29 citations
References
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TL;DR: It is demonstrated that the use of an appropriate hydroxyl-free gate dielectric—such as a divinyltetramethylsiloxane-bis(benzocyclobutene) derivative (BCB; ref. 6)—can yield n-channel FET conduction in most conjugated polymers, revealing that electrons are considerably more mobile in these materials than previously thought.
Abstract: Organic semiconductors have been the subject of active research for over a decade now, with applications emerging in light-emitting displays and printable electronic circuits. One characteristic feature of these materials is the strong trapping of electrons but not holes1: organic field-effect transistors (FETs) typically show p-type, but not n-type, conduction even with the appropriate low-work-function electrodes, except for a few special high-electron-affinity2,3,4 or low-bandgap5 organic semiconductors. Here we demonstrate that the use of an appropriate hydroxyl-free gate dielectric—such as a divinyltetramethylsiloxane-bis(benzocyclobutene) derivative (BCB; ref. 6)—can yield n-channel FET conduction in most conjugated polymers. The FET electron mobilities thus obtained reveal that electrons are considerably more mobile in these materials than previously thought. Electron mobilities of the order of 10-3 to 10-2 cm2 V-1 s-1 have been measured in a number of polyfluorene copolymers and in a dialkyl-substituted poly(p-phenylenevinylene), all in the unaligned state. We further show that the reason why n-type behaviour has previously been so elusive is the trapping of electrons at the semiconductor–dielectric interface by hydroxyl groups, present in the form of silanols in the case of the commonly used SiO2 dielectric. These findings should therefore open up new opportunities for organic complementary metal-oxide semiconductor (CMOS) circuits, in which both p-type and n-type behaviours are harnessed.
2,191 citations
2,020 citations
TL;DR: Recent advances and future prospects of light-emitting field-effect transistors are explored, with particular emphasis on organic semiconductors and the role played by the material properties, device features and the active layer structure in determining the device performances.
Abstract: Field-effect transistors are emerging as useful device structures for efficient light generation from a variety of materials, including inorganic semiconductors, carbon nanotubes and organic thin films. In particular, organic light-emitting field-effect transistors are a new class of electro-optical devices that could provide a novel architecture to address open questions concerning charge-carrier recombination and light emission in organic materials. These devices have potential applications in optical communication systems, advanced display technology, solid-state lighting and electrically pumped organic lasers. Here, recent advances and future prospects of light-emitting field-effect transistors are explored, with particular emphasis on organic semiconductors and the role played by the material properties, device features and the active layer structure in determining the device performances.
858 citations
816 citations
TL;DR: In this article, the authors demonstrate that hole transport and electron transport are both generic properties of organic semiconductors and combine the organic ambipolar transistors into functional CMOS-like inverters.
Abstract: There is ample evidence that organic field-effect transistors have reached a stage where they can be industrialized, analogous to standard metal oxide semiconductor (MOS) transistors. Monocrystalline silicon technology is largely based on complementary MOS (CMOS) structures that use both n-type and p-type transistor channels. This complementary technology has enabled the construction of digital circuits, which operate with a high robustness, low power dissipation and a good noise margin. For the design of efficient organic integrated circuits, there is an urgent need for complementary technology, where both n-type and p-type transistor operation is realized in a single layer, while maintaining the attractiveness of easy solution processing. We demonstrate, by using solution-processed field-effect transistors, that hole transport and electron transport are both generic properties of organic semiconductors. This ambipolar transport is observed in polymers based on interpenetrating networks as well as in narrow bandgap organic semiconductors. We combine the organic ambipolar transistors into functional CMOS-like inverters.
806 citations