Dinaphthotetrathienoacenes: Synthesis, Characterization, and Applications in Organic Field‐Effect Transistors

Abstract

The charge transport of crystalline organic semiconductors is limited by dynamic disorder that tends to localize charges. It is the main hurdle to overcome in order to significantly increase charge carrier mobility. An innovative design that combines a chemical structure based on sulfur-rich thienoacene with a solid-state herringbone (HB) packing is proposed and the synthesis, physicochemical characterization, and charge transport properties of two new thienoacenes bearing a central tetrathienyl core fused with two external naphthyl rings: naphtho[2,3-b]thieno-[2′′′,3′′′:4′′,5′′]thieno[2″,3″:4′,5′]thieno[3′,2′-b]naphtho[2,3-b]thiophene (DN4T) and naphtho[1,2-b]thieno-[2′′′,3′′′:4′′,5′′]thieno[2′′,3′′:4′,5′]thieno[3′,2′-b]naphtho[1,2-b]thiophene are presented. Both compounds crystallize with a HB pattern structure and present transfer integrals ranging from 33 to 99 meV (for the former) within the HB plane of charge transport. Molecular dynamics simulations point toward an efficient resilience of the transfer integrals to the intermolecular sliding motion commonly responsible for strong variations of the electronic coupling in the crystal. Best device performances are reached with DN4T with hole mobility up to 𝝁 = 2.1 cm 2 V −1 s −1 in polycrystalline organic field effect transistors, showing the effectiveness of the electronic coupling enabled by the new aromatic core. These promising results pave the way to the design of high-performing materials based on this new thienoacene, notably through the introduction of alkyl side-chains.

High throughput processing of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) organic semiconductors

“…15,23,24 Again, the use of blends can also help by reducing the required amount of solubilised OSC, commonly by around a factor of 25-50 % depending on the OSC:polymer ratio used. The family of dinaphtho [2,3- 1a) [25][26][27][28][29] derivatives are currently considered as benchmark OSCs since they exhibit high-mobility in organic field-effect transistors (OFETs) and good environmental stability. Due to the poor solubility of the parent DNTT compound, different derivatives have been synthesised in order to gain solubility and afford the processability of these materials from solution.…”

“…Dinaphtho[2,3-b:2′,3′-f ]thieno [3,2-b]thiophene (DNTT, Fig. 1a) [25][26][27][28][29] derivatives are currently considered benchmark OSCs since they exhibit high mobility in organic field-effect transistors (OFETs) and good environmental stability. Due to the poor solubility of the parent DNTT compound, different derivatives have been synthesised in order to achieve better solubility and afford the processability of these materials from solution.…”

Serendipitous Enhancement of the Dimensionality in Diketopyrrolopyrroles through O-Substitution

“…The last two decades have seen increased interest toward the utilization of small organic conjugated materials as charge transport mediators, on account of their highly desirable properties and promising performance when compared to inorganic counterparts . More recently, emphasis has shifted toward design strategies that deliver consistent improvement and capitalize on theoretical material performance in organic field effect transistors (OFETs). , Differences between theoretical (maximum) and experimental performance can be attributed to dynamic disorder, resulting in charges being localized and thus hampering charge transport phenomena. This is largely associated with the thermal integrity of supramolecular motifs and charge propagation channels as a result of unavoidable temperature-induced fluctuations in the equilibrium positions of atoms and molecules.…”

“…In addition, it is widely accepted that larger numbers of short contacts enhance the accessible charge transfer pathways in organic semiconductors. 2 To further evaluate this characteristic in mDoBDPP, we computed the intermolecular interactions for all nonequivalent nearest neighboring dimer pairs as well as a series of systematically cropped versions (Table 1). Unlike other DPP-based architectures, 18−22 we report large (>30 kJ mol −1 ) attractive energies for a number of the identified dimer pairs, namely, II, III, V, VIII (and ΔE CP = −29.05 kJ mol −1 for dimer pair X).…”

“…Next, in light of the role played by short contacts in facilitating charge transport, we evaluated the ability of these dimeric systems to act as charge transfer mediators. 2 In most cases, the self-assembly of diketopyrrolopyrroles results in the generation of one-dimensional slipped cofacial stacking motifs, with transfer integrals approaching or even exceeding those computed for gold standard materials such as rubrene. 23 We have previously demonstrated that double dimensionality can be accessed in DPPs via isosteric fluorine substitution.…”