Tuning molecular energy levels and band gap of two-dimensional benzo[1,2-b:4,5-b′] dithiophene and quinoxaline bearing polymers

Abstract

Two novel donor-acceptor (D-A)-type two-dimensional (2-D) polymers of PBDTSeQ (P1) and PBDTFQ (P2) were synthesized and characterized where 4,8-bis[5-(2-ethylhexyl) thiophen-2-yl] benzo[1,2-b:4,5-b'] dithiophene (BDT) was used as the donor unit. 2,3-Bis(3,4-bis(octyloxy)phenyl)-5,8-dibromoquinoxaline was used as the acceptor moiety and selenophene and furan were utilized as π bridges. Optoelectronic properties of the polymers were examined by electrochemical and spectroelectrochemical characterizations. In cyclic voltammetry (CV) studies, both polymers were found to be ambipolar. In anodic region, oxidation potentials were observed as 1.45 V and 1.15 V for P1 and P2 respectively, while reduction potentials were 0.65 V and 0.92 V. In cathodic region, redox potentials were found to be −1.36 V/−1.32 V and −2.0 V/−1.51 V for P1 and −1.45 V/ −1.05 V and −2.15 V/−1.45 V for P2. Both polymers showed good solubility in common solvents. The synthesized polymers were used as photoactive layers in solar cell devices.

Research progress and application of high efficiency organic solar cells based on benzodithiophene donor materials

“…As for furan π-bridge unit,PFBT-BDT (2011) was first reported by Wang et al [154] , which was designed based on the main chain BDT-Fr-BTDz-Fr; PBDTODFTT (2013) and PBDTTDFTT (2013) were synthesized based on the polymer backbone BDT-Fr-TzTz-Fr; [315] PBDTFQ(P2) (2019)was also prepared based on the polymer skeleton BDT-Fr-Qx-Fr. [316] Among these donors, the highV oc (0.94 V) presented in PBFT-BDT: PC 71 BM based OSC exhibits a promising development potential. Furthermore, PDPP2TzBDT (2015) , [317] PTBTz-5 (2017) , [318] PTBTz-Cl (2019) , [319] PTBTz-Me (2019) [319] , PTSBTz-Me (2022) [320] and PPSBTz-Me (2022) [320] were synthesized by introducing thiazole based π-bridge units.…”

“…Furthermore, the introduction of alkyl substituted thiazole π-bridge is also conducive to further increase the miscibility of polymer donors into the active layer, thereby PTBTz-Me: PC 71 BM based, PTSBTz-Me: PC 71 BM based and PPSBTz-Me: PC 71 BM based OSCs were obtained a relatively higher J sc and FF . Moreover, based on the π-bridge unit selenophene, PBDTTSBO(P3) (2014) , [155] PBDTSSBO(P7) (2014) [155] and P2 (2015) [156] were reported based on the main chain BDT-Sp-BTDz-Sp; PBDTTSBS(P5) (2014) and PBDTSSBS(P8) (2014) were prepared based on the polymer backbone BDT-Sp-BSDz-Sp; [155] J76 (2019) was synthesized based on the polymer skeleton BDT-Sp-BTDz-Sp;BDTSeQ(P1) (2019) , [316] P2 (2022) [201] and P4 (2022) [201] were also designed based on the main-chain engineering BDT-Sp-Qx-Sp, in that order. Notably, compared with the reported results between PFBTFQ: PC 71 BM based and PBDTSeQ: PC 71 BM based OSCs, selenophene π-bridge unit exhibited a high adaptability in main-chain engineering, which endowed PBDTSeQ: PC 71 BM based OSC with an optimized photovoltaic performance.…”

Design Principles for the Acceptor Units in Donor–Acceptor Conjugated Polymers

“…Compounds are identified as follows: A1 , 1,3,4-oxadiazole; A2 , 1,3,4-thiadiazole; A3 , 3,6-dihydro-1,2,4,5-tetrazine; A4 , thiazolo[5,4- d ]thiazole; A5 , 2,2′-bithiazole; A6 , benzo[ c ][1,2,5]thiadiazole; A7 , [1,2,5]thiadiazolo[3,4- c ]pyridine; A8 , 5-fluorobenzo[ c ][1,2,5]thiadiazole; A9 , 5,6-difluorobenzo[ c ][1,2,5]thiadiazole; A10 , 5-ethoxybenzo[ c ][1,2,5]thiadiazole, A11 , 5,6-diethoxybenzo[ c ][1,2,5]thiadiazole; A12 , naphtho[1,2- c :5,6- c ′]bis([1,2,5]thiadiazole); A13 , benzo[ c ][1,2,5]selenadiazole; A14 , benzo[ c ][1,2,5]oxadiazole; A15 , 2,2-dimethyl-2 H -benzo[ d ]imidazole; A16 , 2 H -benzo[ d ][1,2,3]triazole; A17 , 2-methyl-2 H -benzo[ d ][1,2,3]triazole; A18 , 2-ethyl-2 H -benzo[ d ][1,2,3]triazole; A19 , 2-propyl-2 H -benzo[ d ][1,2,3]triazole; A20 , 5,6-difluoro-2-methyl-2 H -benzo[ d ][1,2,3]triazole; A21 , 2,7-dimethyl-2,7-dihydronaphtho[1,2- d :5,6- d ′]bis([1,2,3]triazole); A22 , quinoxaline; , A23 , pyrido[3,4- b ]pyrazine; A24 , 2,3-dimethylpyrido[3,4- b ]pyrazine; A25 , 2,3-difluoroquinoxaline; A26 , pyrazino[2,3- g ]quinoxaline; A27 , 3 a ,4-dihydrothieno[3,4- b ]thiophene; A28 , 5,7-dihydrothieno[3,4- b ]pyrazine; A29 , 5,5-dimethyl-4 H -cyclopenta[ c ]thiophene-4,6(5 H )-dione; A30 , 5-methyl-4 H -thieno[3,4- c ]pyrrole-4,6(5 H )-dione; , A31 , 5-methyl-4 H -thieno[3,4- c ]pyrrole-4,6(5 H )-dione; A32 , naphtho[2,3- c ]thiophene-4,9-dione; A33 , 2,5-dimethylpyrrolo[3,4- c ]pyrrole-1,4(2 H ,5 H )-dione; A34 , ( E )-1,1′-dimethyl-[3,3′-biindolinylidene]-2,2′-dione; A35 , 2-methylisoindoline-1,3-dione; A36 , 3 a ,7 a -dihydrobenzo[1,2- d :4,5- d ′]bis(thiazole); A37 , 3 a ,7 a -dihydrobenzo[1,2- d :4,5- d ′]bis(thiazole); , A38 , 6-methyl-6,8-dihydro-4 H -[1,2,3]triazolo[4′,5′:4,5]benzo[1,2- c ][1,2,5]oxadiazole; A39 , 2,6-dimethyl-2,4,6,8-tetrahydrobenzo[1,2- d :4,5- d ′]bis([1,2,3]triazole), A40 , 6,7-dimethyl[1,2,5]thiadiazolo[3,4- g ]quinoxaline; A41 , 6-methyl-6,8-dihydro-4 H -[1,2,3]triazolo[4′,5′:4,5]benzo[1,2- c ][1,2,5]thiadiazole; A42 , 6-methyl-6,8-dihydro-4 H -[1,2,3]triazolo[4′,5′:4,5]benzo[1,2- c ][1,2,5]selenadiazole; A43 , 4 H ,8 H -benzo[1,2- c :4,5- c ′]bis([1,2,5]thiadiazole); A44 , 2,7-dimethylbenzo[ lmn ][3,8]phenanthroline-1,3,6,8(2 H ,7 H )-tetraone; A45 , 5-methyl-6 a ,9 a -dihydro-4 H -thiazolo[4,5- c ]thieno[2,3- e ]azepine-4,6(5 H )-dione; A46 , 2,6-dimethyl[1,2,3]triazolo[4,5- f ]isoindole-5,7(2 H ,6 H )-dione; A47 , dithieno[3′,2′:3,4;2″,3″:5,6]benzo[1,2- c ][1,2,5]oxadiazole; A...…”

“…Compounds are identified as follows: A1 , 1,3,4-oxadiazole; 14 A2 , 1,3,4-thiadiazole; 15 A3 , 3,6-dihydro-1,2,4,5-tetrazine; 15 A4 , thiazolo[5,4- d ]thiazole; 16 A5 , 2,2′-bithiazole; 17 A6 , benzo[ c ][1,2,5]thiadiazole; 18 A7 , [1,2,5]thiadiazolo[3,4- c ]pyridine; 19 A8 , 5-fluorobenzo[ c ][1,2,5]thiadiazole; 20 A9 , 5,6-difluorobenzo[ c ][1,2,5]thiadiazole; 21 A10 , 5-ethoxybenzo[ c ][1,2,5]thiadiazole, 22 A11 , 5,6-diethoxybenzo[ c ][1,2,5]thiadiazole; 22 A12 , naphtho[1,2- c :5,6- c ′]bis([1,2,5]thiadiazole); 23 A13 , benzo[ c ][1,2,5]selenadiazole; 24 A14 , benzo[ c ][1,2,5]oxadiazole; 25 A15 , 2,2-dimethyl-2 H -benzo[ d ]imidazole; 26 A16 , 2 H -benzo[ d ][1,2,3]triazole; 27 A17 , 2-methyl-2 H -benzo[ d ][1,2,3]triazole; 28 A18 , 2-ethyl-2 H -benzo[ d ][1,2,3]triazole; 28 A19 , 2-propyl-2 H -benzo[ d ][1,2,3]triazole; 28 A20 , 5,6-difluoro-2-methyl-2 H -benzo[ d ][1,2,3]triazole; 28 A21 , 2,7-dimethyl-2,7-dihydronaphtho[1,2- d :5,6- d ′]bis([1,2,3]triazole); A22 , quinoxaline; 29 , 30 A23 , pyrido[3,4- b ]pyrazine; 31 A24 , 2,3-dimethylpyrido[3,4- b ]pyrazine; 31 A25 , 2,3-difluoroquinoxaline; 32 A26 , pyrazino[2,3- g ]quinoxaline; 33 A27 , 3 a ,4-dihydrothieno[3,4- b ]thiophene; A28 , 5,7-dihydrothieno[3,4- b ]pyrazine; 34 A29 , 5,5-dimethyl-4 H -cyclopenta[ c ]thiophene-4,6(5 H )-dione; 35 A30 , 5-methyl-4 H -thieno[3,4- c ]pyrrole-4,6(5 H )-dione; 36 , 37 A31 , 5-methyl-4 H -thieno[3,4- c ]pyrrole-4,6(5 H )-dione; 35 A32 , naphtho[2,3- c ]thiophene-4,9-dione; 35 ...…”