Incorporation of the Benzobisthiadiazole Unit Leads to Open-Shell Conjugated Polymers with n-Type Charge Transport Properties

Abstract

Herein, we report a novel method for constructing polymeric conjugated radicals, introducing an open-shell benzobisthiadiazole (BBT) unit to a (3E,7E)-3,7-bis(2-oxo-1H-pyrrolo-[2,3-b]pyridine-3(2H)ylidene)benzo[1,2-b:4,5-b′]difuran-2,6-(3H,7H)-dione-alt-(E)-1,2-di(thiophen-2-yl)ethene polymeric conjugated backbone (P1 with closed-shell structure) affording conjugated polymers P2−P4 with open-shell characteristics.Through this method, the spin characteristic of the polymer conjugated radicals can also be easily tuned, in which the spin concentration of P2−P4 increases with the increase of the BBT ratio. Moreover, P2−P4 have narrowed energy gaps and n-type charge transport properties with electron mobilities of 0.12−0.35 cm 2 V −1 s −1 , comparable to or higher than those of BBT-containing conjugated polymers reported so far. Microstructural investigations indicated that the gradual decrease of μ e from P1 to P4 originates from their BBT-caused deteriorating molecular aggregations in solid thin films. Our results show that incorporating an open-shell moiety into a high-performance conjugated backbone is a promising method for developing polymeric conjugated radicals with high mobility and tunable open-shell character.

Bisazathienoisoindigo-Based Conjugated Polymers: Synthesis, Characterization, and the Influence of Inner Bridging Units on the Quinoidal Character and Charge Transport Property

“…Therefore, the variation of bands A and B demonstrates that P3 features the weakest quinoidal character even with a larger π-conjugated unit, which is consistent with the bond length analysis. Note that the variation of the electron-acceptor unit did not result in the shift of the collective CC/C–C vibrational peak of DTE (band C centered at 1418 cm –1 ), implying that the quinoidal character is mainly in the acceptors …”

Designer Conjugation-Break Spacer That Boosts Charge Transport in Semiconducting Terpolymers

“…When employing a rigid moiety like DKPDO in CPs, it is important to address the trade-off between polymer solubility and molecular packing. − A facile and cost-effective strategy to address the dilemma is through a random terpolymerization approach by incorporating DKPDO as the third component into parent donor–acceptor CPs. This approach can lead to well-controlled optoelectronic properties, fine-tuned microstructures, as well as well-balanced interchain interactions and solubilities in those terpolymers. ,− In this study, incorporating DKPDO as a CBS into the CP backbone based on IID and bithiophene (2T) gives rise to a series of random terpolymers (Scheme d). Varying the DKPDO/IID ratio in the polymer backbone leads to a balanced control of optoelectronic properties, interchain aggregation, molecular packing, and solubility of those terpolymers.…”

Efficient Iodine Uptake of Ultra Thermally Stable Conjugated Copolymers Bearing Biaceanthrylenyl Moieties and Contorted Aromatic Units Using a [3 + 2] Palladium-Catalyzed Cyclopolymerization Reaction

“…Conjugated polymers emerged as a fascinating family of materials which have revolutionized various fields of science and technology − because of their exceptional optical and electronic properties bestowed with their versatile processability, thus allowing for their use across a myriad of applications, notably, optoelectronic devices and energy storage and conversion. − These applications encompass organic photodetectors and photovoltaics (OPDs and OPVs), , light-emitting diodes (OLEDs), and field-effect transistors (OFETs). , …”