Electrode and dielectric layer interface device engineering study using furan flanked diketopyrrolopyrrole–dithienothiophene polymer based organic transistors

Abstract

We successfully demonstrated a detailed and systematic enhancement of organic field effect transistors (OFETs) performance using dithienothiophene (DTT) and furan-flanked diketopyrrolopyrrole based donor–acceptor conjugated polymer semiconductor namely PDPPF-DTT as an active semiconductor. The self-assembled monolayers (SAMs) treatments at interface junctions of the semiconductor–dielectric and at the semiconductor–metal electrodes has been implemented using bottom gate bottom contact device geometry. Due to SAM treatment at the interface using tailored approach, the significant reduction of threshold voltage (Vth) from − 15.42 to + 5.74 V has been observed. In addition to tuning effect of Vth, simultaneously charge carrier mobility (µFET) has been also enhanced the from 9.94 × 10−4 cm2/Vs to 0.18 cm2/Vs. In order to calculate the trap density in each OFET device, the hysteresis in transfer characteristics has been studied in detail for bare and SAM treated devices. Higher trap density in Penta-fluoro-benzene-thiol (PFBT) treated OFET devices enhances the gate field, which in turn controls the charge carrier density in the channel, and hence gives lower Vth = + 5.74 V. Also, PFBT treatment enhances the trapped interface electrons, which helps to enhance the mobility in this OFET architecture. The overall effect has led to possibility of reduction in the Vth with simultaneous enhancements of µFET in OFETs, following systematic device engineering methodology.

Solution-processed ambipolar organic thin-film transistors and inverters in a single substrate through self-assembled monolayer-treated electrodes

“…30,31 This can help to alleviate the hysteresis in the transfer characteristics by reducing the trap density at the electrode/semiconductor layer interface. 32,33 Due to the influence of the SAM treatment on the hydrophobicity of the electrode, it is anticipated that the morphology of the semiconducting layer formed on the SAM-treated electrode will be changed. 34 Therefore, we examined the morphology of the semiconducting layer formed on both the untreated and SAM-treated Au electrodes using atomic force microscopy (AFM) as shown in Fig.…”

“…This is attributed to an improvement in the molecular orientation of PNDI-TVT by PFBT. 22,33 To investigate the changes in the microstructure of the PNDI-TVT films formed on untreated and SAM treated Au electrodes, we measured Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) patterns for both types of films. Fig.…”

Low-Voltage Organic Field-Effect Transistors: Challenges, Progress, and Prospects

“…For the oxide dielectrics, there are an abundance of carrier trap groups on their surfaces, for example, −OH groups on the SiO 2 substrate. , Utilizing a passivation layer is a simple but effective method to eliminate the adverse impact of −OH groups on OFET performance. Maeda et al reported the use of n -doped LaB 6 as a passivation layer to passivate interfacial traps.…”

Dithieno[3,2-b:2′,3′-d]thiophene (DTT): an emerging heterocyclic building block for future organic electronic materials & functional supramolecular chemistry

“…These substances are also highly efficient in hole transport, photoconductors, study of interface engineering, and so on. 58,59 Moreover, the conjugated microporous polymers (CMPs) are easy to functionalize and poses various applications like organic electronics, photovoltaics, sensing and so forth, and it has been noticed that through the incorporation of fused thiophenes into the CMPs enhanced their performances. [60][61][62][63] To this context, the research groups of Ozturk & Thomas have constructed DTT-CMPs by means of bulk and electrochemical oxidative polymerization reactions (Scheme 1).…”