A Thiazolothiazole-Based Semiconducting Polymer with Well-Balanced Hole and Electron Mobilities

Masahiko Saito,Itaru Osaka

doi:10.3390/app9030451

Abstract

We report the synthesis and properties of a new thiazolothiazole (TzTz)-based semiconducting polymer incorporating the dithienothienothiophenebisimide (TBI) unit, named PTzTBI. PTzTBI showed relatively deep HOMO and LUMO energy levels of −5.48 and −3.20 eV, respectively. Although PTzTBI mainly formed face-on backbone orientation unfavorable for transistors, PTzTBI functioned as an ambipolar semiconductor for the first time with TzTz-based polymers, with reasonably high and well-balanced hole (0.02 cm2 V−1 s−1) and electron (0.01 cm2 V−1 s−1) mobilities.

Highlights

Semiconducting polymers have been widely used in various organic electronic devices such as field-effect transistors (OFETs), photovoltaics (OPVs), or light-emitting diodes (OLEDs), due to their good electrical and optical properties and solution processability [1,2,3,4,5]
One plausible reason is that strong electron-deficient building units, which can lower the lowest unoccupied molecular orbital (LUMO) energy level of the semiconducting polymers and thereby ensure electron transportation, are not in abundance
Scheme 1 displays the synthesis of PTzTBI, in which PTzTBI was synthesized using the distannylated TzTz monomer (1) and the dibrominated the dithienothienothiophenebisimide (TBI) monomer (2) via the Stille coupling reaction

Summary

Introduction

Semiconducting polymers have been widely used in various organic electronic devices such as field-effect transistors (OFETs), photovoltaics (OPVs), or light-emitting diodes (OLEDs), due to their good electrical and optical properties and solution processability [1,2,3,4,5]. Through studies on polymer-based OFETs in recent decades, the community has seen significant improvements in the charge carrier mobility and has come to better understand the charge transport in thin films. Thiazolothiazole (TzTz) (Figure 1a) is an electron-deficient unit that was introduced in semiconducting polymers as well as molecules in the earlier stage, and has provided high-performance materials for OFETs as well as OPVs [11,12,13,14,15,16,17,18].

Methods

Results

Conclusion