Light‐Modulation of the Charge Injection in a Polymer Thin‐Film Transistor by Functionalizing the Electrodes with Bistable Photochromic Self‐Assembled Monolayers

Mosciatti, Thomas; Rosso, Maria G. del; Herder, Martin; Frisch, Johannes; Koch, Norbert; Hecht, Stefan; Orgiu, Emanuele; Samorı́, Paolo

doi:10.1002/adma.201600651

Cited by 63 publications

(53 citation statements)

References 36 publications

(45 reference statements)

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“…Recently, the concept of incorporating photoswitchable molecules in SAMs has been introduced to generate bistable systems providing a dynamic control over the work function shift and hence on the charge injection barriers . Prototypical molecules are azobenzene derivatives that can be switched reversibly between the trans and cis states under illumination.…”

Section: Introductionmentioning

confidence: 95%

Effect of the Molecular Polarizability of SAMs on the Work Function Modification of Gold: Closed‐ versus Open‐Shell Donor–Acceptor SAMs

Diez‐Cabanes

Morales

Souto

et al. 2018

Adv Materials Technologies

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Charge injection barriers at metal/organic interfaces can be tuned by modifying the work function of metallic electrodes using self‐assembled monolayers (SAMs) of polar molecules. An interesting example of polar molecules is offered by donor–acceptor (D–A) dyads based on ferrocene (Fc) as electron‐donor unit and either a polychlorotriphenylmethyl radical or a polychlorotriphenylmethane as electron‐acceptor units, connected by a π‐conjugated vinylene bridge. The D–A radical exhibits high chemical and thermal stability and presents different electronic, optical, and magnetic properties with respect to the closed‐shell form. The magnitude of the shift in the charge injection barriers for these two D–A systems is estimated by means of surface potential measurements performed by Kelvin probe force microscopy. The experimental data are compared with density functional theory calculations, which evidence the importance of the molecular dipole moments and polarizabilities to understand the experimental values. In order to achieve high work function shifts of metals upon SAM formation, the molecules forming the SAM have to exhibit both a high permanent dipole moment and a low polarizability along the direction normal to the substrate. In presence of polarizable molecules, the work function shifts can be enhanced by reducing the intermolecular interactions; by using mixed SAMs with active molecules embedded into a passive matrix.

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Section: Introductionmentioning

confidence: 95%

Effect of the Molecular Polarizability of SAMs on the Work Function Modification of Gold: Closed‐ versus Open‐Shell Donor–Acceptor SAMs

Diez‐Cabanes

Morales

Souto

et al. 2018

Adv Materials Technologies

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“…These molecules have been combined with organic semiconductors in order to control the overall material's properties and thus device performance with an optical input, resulting in light‐responsive diodes, transistors, and memories . Photochromic molecules were placed at the semiconductor–insulator interface, as a self‐assembled monolayer on the electrodes, or blended with organic semiconductors to control optical and electrical characteristics. Among photochromic molecules, diarylethene derivatives are very promising building blocks, combining good thermal stability and fatigue resistance .…”

Section: Introductionmentioning

confidence: 99%

Phototuning Selectively Hole and Electron Transport in Optically Switchable Ambipolar Transistors

Rekab

Leydecker

Hou

et al. 2019

Adv Funct Materials

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One of the grand challenges in organic electronics is to develop multicomponent materials wherein each component imparts a different and independently addressable property to the hybrid system. In this way, the combination of the pristine properties of each component is not only preserved but also combined with unprecedented properties emerging from the mutual interaction between the components. Here for the first time, that tricomponent materials comprised of an ambipolar diketopyrrolopyrrole-based semiconducting polymer combined with two different photochromic diarylethene molecules possessing ad hoc energy levels can be used to develop organic field-effect transistors, in which the transport of both, holes and electrons, can be photo-modulated. A fully reversible light-switching process is demonstrated, with a light-controlled 100-fold modulation of p-type charge transport and a tenfold modulation of n-type charge transport. These findings pave the way for photo-tunable inverters and ultimately for completely readdressable high-performance circuits comprising optical storage units and ambipolar field-effect transistors.

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“…In addition to thin films, also SAMs have been used to modulate charge injection barriers. Incorporating thiol anchoring groups into the structure of DAEs was used to prepare SAMs on a gold electrode, which allowed for switching of device characteristics by light when applied in an organic thin‐film transistor (OTFT) . This research endeavor is an important step toward multifunctional optoelectronic devices, in which several interfaces are brought together that can be addressed individually by external stimuli to gain control over the electrical output of an electric device.…”

Section: Photoswitches On Surfacesmentioning

confidence: 99%

Enlightening Materials with Photoswitches

2020

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reversible conversion between their stable and (meta)stable isomers triggered by light. The return to their native, thermo dynamically most stable isomer is gener ally induced by using another wavelength of light or simply by heat, depending on the thermal stability of the (meta)stable isomer. Retinal-the prototypical photo switch in biology-showcases impressively how structural changes occurring during a lightinduced doublebond isomerization can lead to vision or allow microorganisms to convert photons into metabolic energy. In analogy, over the years, scientists have learned that the lightdriven isomeriza tion of small molecules can be collected, possibly amplified, and transformed into macroscopic property changes, such as mechanical motion, [1] charge carrying ability, [2] assembly and disassembly of macroscopic aggregates, [3] as well as switching of surfaces and their properties. [4] Materials, which for the purpose of this review are consid ered to be solid objects or organized assemblies in solution, provide unique advantages to enhance the function of photo switches and even create new functions when compared to their standalone molecular selves (for the primarily discussed photochromic molecules herein, see Figure 1). One must, how ever, consider the inherent challenges that may present them selves when working with photoswitches in close proximity to one another. Intermolecular interactions, such as aggregation, excitation quenching, low freevolume, as well as the poten tially much higher optical density of materials can drastically lower the overall photoresponse. Yet with proper macromo lecular and supramolecular design, functions can be achieved through the incorporation of photoswitches in a material that simply cannot be obtained by an isolated molecule on its own. Here, we highlight recent examples from the literature that have appeared during the past decade since our previous review in this journal, [5] with particular focus on the order of the photos witches in relation to their environment and its impact on mate rial properties and device performance.Conceptually, one can think about maximizing a photo switching unit's effect by giving it "order" with relation to its surrounding, in particular to other switching units (Figure 2). The lowest possible order is undoubtedly demonstrated by dis persing photochromic molecules in a bulk amorphous material. If aggregation of the photoswitches can be overcome, switching units are placed in random orientation to each other giving rise to a more or less isotropic material. Starting from this scenario of randomly distributed photochromic entities, one can think about providing order in two dimensions by placing Incorporating molecular photoswitches into various materials provides unique opportunities for controlling their properties and functions with high spatiotemporal resolution using remote optical stimuli. The great and largely still untapped potential of these photoresponsive systems has not yet been fully exploited due to the fundamental challenge...

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Light‐Modulation of the Charge Injection in a Polymer Thin‐Film Transistor by Functionalizing the Electrodes with Bistable Photochromic Self‐Assembled Monolayers

Abstract: High fatigue resistance, bistability, and drastic property changes among isomers allow efficient modulation of the current output of organic thin-film transistors (OTFTs) to be obtained by a photogating of the charge-injection mechanism.

Cited by 63 publications

References 36 publications

Effect of the Molecular Polarizability of SAMs on the Work Function Modification of Gold: Closed‐ versus Open‐Shell Donor–Acceptor SAMs

Effect of the Molecular Polarizability of SAMs on the Work Function Modification of Gold: Closed‐ versus Open‐Shell Donor–Acceptor SAMs

Phototuning Selectively Hole and Electron Transport in Optically Switchable Ambipolar Transistors

Enlightening Materials with Photoswitches

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