Very Low Band Gap Thiadiazoloquinoxaline Donor–Acceptor Polymers as Multi-tool Conjugated Polymers

Abstract

Here we report on the synthesis of two novel very low band gap (VLG) donor-acceptor polymers (Eg ≤ 1 eV) and an oligomer based on the thiadiazoloquinoxaline acceptor. Both polymers demonstrate decent ambipolar mobilities, with P1 showing the best performance of ∼10(-2) cm(2) V(-1) s(-1) for p- and n-type operation. These polymers are among the lowest band gap polymers (≲0.7 eV) reported, with a neutral λmax = 1476 nm (P2), which is the farthest red-shifted λmax reported to date for a soluble processable polymer. Very little has been done to characterize the electrochromic aspects of VLG polymers; interestingly, these polymers actually show a bleaching of their neutral absorptions in the near-infrared region and have an electrochromic contrast up to 30% at a switching speed of 3 s.

Thiadizoloquinoxaline-Based Low-Bandgap Conjugated Polymers as Ambipolar Semiconductors for Organic Field Effect Transistors

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Most TQ-based polymers have been reported to show hole transport, while only few of them were presented as ambipolar semiconductors. 27,32,33 However, these systems usually exhibited very low mobilities (≤ 10 -2 cm 2 V -1 s -1 ) in OFETs. Two reasons may lead to low charge carrier mobility and limit their application in optoelectronic devices.…”

Thiadiazole quinoxaline-based copolymers with ∼1.0 eV bandgap for ternary polymer solar cells

“…The remarkable property has enabled NDF-based PSCs to achieve PCEs of ~5% [33][34][35]. However, the synthesis of quinoxaline-based polymers with low bandgaps is challenging and has been relatively less explored [36][37][38][39][40]. Previous [1,2,5]thiadiazolo [3,4-g]quinoxaline-based polymers have proven useful as the active materials in organic solar cells and organic field-effect transistors [39,40].…”

2,1,3-Benzothiadiazole-5,6-dicarboxylic imide based low-bandgap polymers for solution processed photodiode application

“…Fusing another electro-withdrawing ring is an alternative method to resolve the problem. Benzobisthiadiazole (BBT) [23] and thiadiazoloquinoxaline (TQ) [24] are two well-known acceptors which can effectively extend absorptions to the NIR region. However, the LUMO orbitals of the resultant polymers are too low for normal exciton separation and charge transfer in the system of bulk heterojunction with PC 61 BM as an acceptor.…”