title: Dithienobenzothiadiazole-based conjugated polymer: processing solvent-relied interchain aggregation and device performances in field-effect transistors and polymer solar cells.
abstract: DTfBT-Th(3), a new conjugated polymer based on dithienobenzothiadiazole and terthiophene, possesses a bandgap of ≈1.86 eV and a HOMO level of -5.27 eV. Due to strong interchain aggregation, DTfBT-Th(3) can not be well dissolved in chloro-benzene (CB) and o-dichlorobenzene (DCB) at room temperature (RT), but the polymer can be processed from hot CB and DCB solutions of ≈100 °C. In CB, with a lower solvation ability, a certain polymer chain aggregation can be preserved, even in hot solution. DTfBT-Th(3) displays a field-effect hole mobility of 0.55 cm(2) V(-1) s(-1) when fabricated from hot CB solution, which is higher than that of the device processed from hot DCB (0.16 cm(2) V(-1) s(-1) In DTfBT-Th(3) -based polymer solar cells, a good power conversion efficiency from 5.37% to 6.67% can be achieved with 150-300 nm thick active layers casted from hot CB solution, while the highest efficiency for hot DCB-processed solar cells is only 5.07%. The results demonstrate that using a solvent with a lower solvation ability, as a "wet control" process, is beneficial to preserve strong interchain aggregation of a conjugated polymer during solution processing, showing great potential to improve its performances in optoelectronic devices.
authors.affiliation: Institute of Polymer Optoelectronic Materials & Devices, State Key Laboratory of Luminescent Materials & Devices, South China University of Technology, Guangzhou, 510640, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Huang
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Junwu
authors.initials: J
authors.lastname: Chen
authors.forename: Lianjie
authors.initials: L
authors.lastname: Zhang
authors.forename: Junbiao
authors.initials: J
authors.lastname: Peng
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
mesh_terms: D011211:Electric Power Supplies; D055664:Electrochemical Techniques; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D012993:Solar Energy; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D013830:Thiadiazoles / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D011108:Polymers; D012997:Solvents; D013830:Thiadiazoles; D013876:Thiophenes; C019101:alpha-terthienyl
keywords: D-A conjugated copolymers; dithienobenzothiadiazoles; organic field-effect transistors; polymer solar cells; salvation ability