Tuning the Charge Carrier Polarity of Organic Transistors by Varying the Electron Affinity of the Flanked Units in Diketopyrrolopyrrole‐Based Copolymers

Abstract

Fine‐tuning of the charge carrier polarity in organic transistors is an important step toward high‐performance organic complementary circuits and related devices. Here, three new semiconducting polymers, namely, pDPF‐DTF2, pDPSe‐DTF2, and pDPPy‐DTF2, are designed and synthesized using furan, selenophene, and pyridine flanking group‐based diketopyrrolopyrrole cores, respectively. Upon evaluating their electrical properties in transistor devices, the best performance has been achieved for pDPSe‐DTF2 with the highest and average hole mobility of 1.51 and 1.22 cm2 V−1 s−1, respectively. Most intriguingly, a clear charge‐carrier‐polarity change is observed when the devices are measured under vacuum. The pDPF‐DTF2 polymer exhibits a balanced ambipolar performance with the µh/µe ratio of 1.9, whereas pDPSe‐DTF2 exhibits p‐type dominated charge carrier transport properties with the µh/µe ratio of 26.7. Such a charge carrier transport change is due to the strong electron‐donating nature of the selenophene. Furthermore, pDPPy‐DTF2 with electron‐withdrawing pyridine flanking units demonstrates unipolar n‐type charge transport properties with an electron mobility as high as 0.20 cm2 V−1 s−1. Overall, this study demonstrates a simple yet effective approach to switch the charge carrier polarity in transistors by varying the electron affinity of flanking groups of the diketopyrrolopyrrole unit.

Tailoring Trap Density of States through Impedance Analysis for Flexible Organic Field‐Effect Transistors

“…[ 7–9 ] Mobility values of OFETs are now challenging the mobility of amorphous Silicon. [ 10–13 ] For further development of a reliable OFET device, other parameters related to the dielectric layer and the dielectric/semiconductor (D/S) interface needs to be extensively studied.…”

Short Alkyl Chain Engineering Modulation on Naphthalene Flanked Diketopyrrolopyrrole toward High‐Performance Single Crystal Transistors and Organic Thin Film Displays

“…Diketopyrrolopyrrole (DPP) derivatives have proven to be an important class of high‐performance organic semiconductors that can be used as active materials in various types of electronic devices. [ 1–7 ] As representative examples, the power conversion efficiency (PCE) of organic photovoltaic (OPV) devices have reached more than 12% by using some DPP derivatives as the active layer materials. [ 8,9 ] In DPP semiconductors for organic thin film transistors (OTFTs), impressive hole mobilities exceeding 10 cm 2 V −1 s −1 have been demonstrated.…”

Recent structural evolution of lactam- and imide-functionalized polymers applied in organic field-effect transistors and organic solar cells

“…By changing the donor to a uorinated bithiophene unit, Liu and co-workers synthesized the selenophene-DPP-based polymer (P11) with a lowered HOMO energy level. 34 The easier hole carrier injection gave a much improved hole mobility of 0.95 cm 2 V À1 s À1 compared with the hole mobilities of P9 and P10. Besides, the additional NMe 4 I contributed a higher hole mobility of up to 1.51 cm 2 V À1 s À1 under ambient conditions, indicating its further potential in better FET performance.…”

“…As a popular molecule in pigment chemistry, DPP contains two lactam groups and has been increasingly applied in the eld of organic electronics during the past several years. [21][22][23] Multiple polymeric materials have been designed and synthesized based on the DPP unit, due to its proper frontier molecular orbital (FMO) energy levels and its adjustable molecular structure. To sum up, there are two main ways to construct a new type of electron-accepting DPP-based unit.…”