Tuning the optoelectronic properties of dual-acceptor based low-bandgap ambipolar polymers by changing the thiophene-bridge length

Abstract

Three very-low-bandgap dual-acceptor based polymers containing diketopyrrolopyrrole (DPP) and a thiadiazoloquinoxaline (TQ) derivative were prepared. Both acceptors in these polymers were separated by one, two and three thiophenes. Only inserting one thiophene between DPP and benzodithiophene condensed TQ, polymer PDPP-T-TQ has a very low optical bandgap of 0.60 eV with the electron affinity of -4.23 eV. Optical and electrochemical bandgaps of the polymers were enlarged with increasing the thiophene-bridge length between both acceptors. GIWAXS measurements confirmed that polymer with three thiophene bridges (PDPP-3T-TQ) showed an ordered arrangement of the crystallites, providing a best ambipolar device performance among these polymers.

Protonation tuning of quantum interference in azulene-type single-molecule junctions

“…The protonation of azulene could lead to the formation of stable tropylium cations, which causes significantly different properties compared with the neutral species. 23 – 27 …”

Effect of fluorination of naphthalene diimide–benzothiadiazole copolymers on ambipolar behavior in field-effect transistors

“…In diluted chloroform solution, the absorption spectra proles of both polymers exhibit three bands, which are similar to other dual-acceptor based polymers. 24 The region of 300-400 nm and 400-550 nm should origin from p-p* transitions of NDI and BT (or FBT) units, respectively. 8,33,34 The vis-NIR region (550-850 nm) is attributed to intramolecular charge transfer (ICT) between the NDI and T-BT (or T-FBT) in the polymer backbone.…”

“…Thereby, oen stronger acceptors as BBT or TQ possess high electron deciency providing well balanced ambipolar characteristics via combination with weaker acceptors as DPP. 17,24 The FET performances of conjugated polymers are also dependent on their side chains. The side chain geometries have crucial inuence on molecular solubility, packing and thin-lm organization, and hence on device performance.…”

Recent advances in rylene diimide polymer acceptors for all-polymer solar cells

“…Naturally, people consider combining both of the promising units in one polymer backbone to design (D-A1)-(D-A2) terpolymers. Such a dual-acceptor design concept has been proposed for n-type or ambipolar OFET polymer semiconductors [79]. In this way, the optoelectronic and materials properties of the resulting polymers can be tuned via varying the composition of the two electron acceptors.…”