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Morphology Driven by Molecular Structure of Thiazole‐Based Polymers for Use in Field‐Effect Transistors and Solar Cells
Author(s) -
Hong Jisu,
Wang Canjie,
Cha Hyojung,
Kim Hyung Nam,
Kim Yebyeol,
Park Chan Eon,
An Tae Kyu,
Kwon SoonKi,
Kim YunHi
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804803
Subject(s) - thiazole , materials science , morphology (biology) , polymer , nanotechnology , optoelectronics , chemistry , biology , organic chemistry , composite material , genetics
The effects of the molecular structure of thiazole‐based polymers on the active layer morphologies and performances of electronic and photovoltaic devices were studied. Thus, thiazole‐based conjugated polymers with a novel thiazole‐vinylene‐thiazole (TzVTz) structure were designed and synthesized. The TzVTz structure was introduced to extend the π conjugation and coplanarity of the polymer chains. By combining alkylthienyl‐substituted benzo[1,2‐ b :4,5‐ b ′]dithiophene (BDT) or dithieno[2,3‐ d :2′,3′‐ d ′]benzo[1,2‐ b :4,5‐ b ′]dithiophene (DTBDT) electron‐donating units and a TzVTz electron‐accepting unit, enhanced intermolecular interactions and charge transport were obtained in the novel polymers BDT‐TzVTz and DTBDT‐TzVTz. With a view to using the polymers in transistor and photovoltaic applications, the molecular self‐assembly in and their nanoscale morphologies of the active layers were controlled by thermal annealing to enhance the molecular packing and by introducing a diphenyl ether solvent additive to improve the miscibility between polymer donors and [6,6]phenyl‐C71‐butyric acid methyl ester (PC 71 BM) acceptors, respectively. The morphological characterization of the photoactive layers showed that a higher degree of π‐electron delocalization and more favorable molecular packing in DTBDT‐TzVTz compared with in BDT‐TzVTz leads to distinctly higher performances in transistor and photovoltaic devices. The superior performance of a photovoltaic device incorporating DTBDT‐TzVTz was achieved through the superior miscibility of DTBDT‐TzVTz with PC 71 BM and the improved crystallinity of DTBDT‐TzVTz in the nanofibrillar structure.