Flexible organic field-effect transistors based on 6,13-bis(triisopropylsilylethynyl) pentacene/polystyrene blend film prepared by electrostatic spray deposition

Abstract

In this study, we fabricated flexible organic field-effect transistors (OFETs) (bottom-gate and top-contact architecture) based on the blend film composed of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) as a π-conjugated small-molecule semiconductor and polystyrene (PS) as a polymer insulator. Blend solutions including both the TIPS pentacene and PS molecules were electrosprayed onto bottom-gate electrodes which were patterned on polyethylene naphthalate films. The devices exhibited superior electrical characteristics due to well-defined vertical phase separation between the TIPS pentacene crystalline layer (top) and PS insulator (bottom). This study will contribute to a facile one-step printing process to produce high-performance flexible OFETs.

Binary solvent engineering for small-molecular organic semiconductor crystallization

“…One successful pathway to obtain a desirable morphology is to mix organic semiconductors with polymer additives. 56,57 Amorphous polymers including poly(a-methylstyrene) (PaMS), [58][59][60][61][62] poly(methyl methacrylate) (PMMA), [63][64][65][66][67][68] polystyrene (PS), [69][70][71][72][73][74] and poly(triaryl)amine (PTAA) [75][76][77][78][79] can both improve the semiconductor film uniformity and induce a vertically phase-separated active layer structure. This further forms a semiconductor sublayer with an elevated semiconductor concentration at the dielectric layer interface, 80,81 and/or a polymer encapsulation layer at the air interface, 82,83 which favors the charge transport and air stability of the transistor device.…”

Tailoring the molecular weight of polymer additives for organic semiconductors

“…Miscellaneous polymer additives have been extensively studied to mix with solution processable, small molecular organic semiconductors [124][125][126][127][128][129]. When the polymer additives are mixed with semiconducting small molecules, the resultant binary system can benefit from improved semiconductor morphology uniformity [130][131][132][133][134], phase segregation-enhanced charge transport [135][136][137][138][139] and operational device stability [140][141][142][143][144][145][146][147]. In this section, we will briefly discuss the benefits of mixing organic semiconductors with different categories of polymer additives, including amorphous polymers, conjugated polymers and semicrystalline polymers.…”

Low activation energy field-effect transistors fabricated by bar-assisted meniscus shearing

“…Previous works also highlighted the effectiveness of co-processing OSCs with insulating polymers to reduce the negative impacts of traps [43][44][45] , without the need to modify the dielectric, which requires significant alterations to standard workflows. This is due to the vertical phase segregation between the OSC and some insulating polymers, such as polystyrene (PS) 46 , which sit at the bottom and leads to considerable passivation of interfacial traps [47][48][49] . Further, combining the blending approach with a bar coating deposition technique allowed to produce high quality devices and potentially compatible with up-scaling to large areas 50 .…”