Bis‐Diketopyrrolopyrrole Moiety as a Promising Building Block to Enable Balanced Ambipolar Polymers for Flexible Transistors

Abstract

A bis-diketopyrrolopyrrole (DPP dimer, 2DPP) core is synthesized with much stronger electron deficiency than DPP by homocoupling of DPP. 2DPP-based polymers, P2DPP-BT, P2DPP-TT, P2DPP-TVT, and P2DPP-BDT, are obtained. Top-gated organic field-effect transistors on plastic substrate are fabricated. Compared with their mono-DPP-based polymers, remarkable improvement of electron mobilities of P2DPPs is achieved. Meanwhile, their p-channel performance becomes higher.

Ambipolar Conjugated Polymers with Ultrahigh Balanced Hole and Electron Mobility for Printed Organic Complementary Logic via a Two‐Step CH Activation Strategy

“…For instance, spin‐coated PDBD‐Se exhibits maximum hole and electron mobilities up to 8.90 and 7.71 cm 2 V −1 s −1 as top‐gated flexible OFETs. This result presents the highest performance for DPP‐based materials with balanced ambipolar properties to date . It should be emphasized that DBD was synthesized using an all CH activation/arylation strategy, thus simplifying multiple synthetic steps and toxic organostannes required by Stille polycondensation .…”

“…More significantly, as a result of DPP electron deficiency, its conjunction with electron donating comonomer units afford donor–acceptor (D–A) type copolymers, allowing ambipolar transport properties using only one material in the channel . This advantage avoids the separate fabrication of p‐type and n‐type FET in conventional complementary metal‐oxide‐semiconductor (CMOS) logic gates …”

“…Meanwhile, resultant polymers' highest occupied molecular orbitals (HOMO) are also deepened to affect hole transport . In general, very few DPP copolymers manage to demonstrate balanced hole and electron mobility simultaneously over 5 cm 2 V −1 s −1 , a benchmark quantifying copolymers for driving and logic utilities . Even crucial, a majority of DPP copolymers including PDPP‐TT, PDQT, and PDVT show a critical mobility dependence on polymerization degree, requiring high molecular weight fraction to fully obtain their maximum performance.…”

Thiazole Imide‐Based All‐Acceptor Homopolymer: Achieving High‐Performance Unipolar Electron Transport in Organic Thin‐Film Transistors

“…In order to overcome synthetic barrier and to reduce steric hindrance, n‐type polymers are mostly based on the donor−acceptor (D–A) strategy, exemplified by the P(NDI2OD‐T2) and BDOPV‐2T ( Figure a). However, the electron‐rich donor counits, such as bithiophene, can elevate both the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO), leading to high off‐currents ( I off s), small current on/off ratios ( I on / I off s), and ambipolarity in OTFTs . Although ambipolar semiconductors show some attractions, their applications greatly suffer from unbalanced hole/electron mobilities and large leakage currents .…”

Conjugated D–A terpolymers for organic field-effect transistors and solar cells

“…In fact, polymeric p-type, n-type and even ambipolar semiconductors with high charge mobilities have been developed on the basis of conjugated D-A polymers. [18][19][20][21] Moreover, conjugated D-A polymers have been successfully utilized as either electron donors or acceptors for OSCs with high power conversion efficiencies (PCEs). [22][23][24][25] Apart from conjugated polymers with alternating electron donor and acceptor moieties, conjugated D-A terpolymers, which contain either one kind of acceptor/two types of electron donors (2D1A) or one kind of donor/two types of electron acceptors (1D2A) in the backbones as illustrated in Scheme 1, have received increased attention.…”