Selenophene-bearing low-band-gap conjugated polymers: tuning optoelectronic properties via fluorene and carbazole as donor moieties

Abstract

In this study, two donor-acceptor (D-A)-type conjugated polymers, namely PQSeCz and PQSeFl, were designed and synthesized. Selenophene was incorporated as the π-bridge and quinoxaline as an acceptor unit, while carbazole and fluorene were used as the donor units. Polymers were synthesized via palladium-catalyzed Suzuki polymerization reaction. All molecules were characterized by 1 H and 13 C NMR spectroscopy. The weight and number average molecular weights of the two polymers were determined by gel permeation chromatography. Electrochemical and spectroelectrochemical characterizations of the polymers were performed to investigate their optoelectronic properties. Oxidation potentials were 1.15 V/0.82 V and 1.11 V/0.82 V for PQSeCz and PQSeFl, respectively, while reduction potentials were − 1.26 V/− 1.14 V and − 1.48 V/− 1.20 V, respectively. In the visible region, maximum absorption wavelengths for the two polymers were 551 nm and 560 nm, respectively. Optical band gaps (E g op) were found from the lowest energy π-π* transition onsets as 1.67 eV for PQSeCz and 1.51 eV for PQSeFl, respectively. Both polymers showed good solubility in common solvents.

Selenophene‐containing conjugated polymers for supercapacitor electrodes

“…The selenophene‐containing conjugated polymers, poly[2‐(5‐(2,3‐bis(3,4‐bis[octyloxy]phenyl)‐8‐(selenophen‐2‐yl)quinoxalin‐5‐yl)selenophen‐2‐yl)‐9‐(heptadecan‐9‐yl)‐9H‐carbazole]‐ CP1 and poly[2,3‐bis(3,4‐bis[octyloxy]phenyl)‐5‐(5‐[9,9‐dioctyl‐9H‐fluoren‐2‐yl]selenophen‐2‐yl)‐8‐(selenophen‐2‐yl)quinoxaline]‐ CP2 were previously synthesized via Suzuki Polycondensation reaction and reported 39 . Scheme 1 represents the synthetic route for CP1 and CP2.…”

“…The polymers comprise quinoxaline units as the acceptors and fluorene and carbazole moieties as the donors. The syntheses and optoelectronic properties of the two polymers were previously reported 39 . Carbazole is one the most used moieties in plastic electronics applications due to its promising properties like high charge carrier mobility, hole‐transport capacity, morphological and photophysical capacity.…”

Quinoxaline‐Based D–A Copolymers for the Applications as Polymer Donor and Hole Transport Material in Polymer/Perovskite Solar Cells

“…In 2019, Yasa et al developed two Qx-based D-A copolymer donors PQSeCz and PQSeFl (Figure 1) based on carbazole or fluorene as D-unit and selenophene as π-bridges. [53] Due to the lower ionization potential of selenophene, the introduction of selenophene π-bridges effectively downshifted the LUMO energy level of the polymers, which results in a reduced optical bandgap of the D-A copolymers. Therefore, PQSeCz and PQSeFl exhibit a narrow bandgap of 1.67 and 1.53 eV (Table 1), respectively.…”

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 ...…”