Synthesis and Self-Assembly of All-conjugated PPP-P3BT Rod-Rod Block Copolymers via Grignard Metathesis Polymerization and Their Applications in Nanohybrid System
Date Issued
2014
Date
2014
Author(s)
Yang, Yi-Lung
Abstract
Recently, all-conjugated block copolymers of the rod-rod type has been developed into a new kind of conjugated polymer materials, and came into the focus of interest because of their unique and attractive combination of optoelectronic activity and controllable nanostructure formation. Compared with coil-based block copolymer systems, there is considerable interest for the co-self-assembly behavior of rod-rod block copolymer system in organic electronics applications. The co-self-assembly behavior of a rod-rod system is further complicated due to the presence of the anisotropic interaction between the rod blocks.
In Chapter 2 of this thesis, the self-assembly behavior of all-conjugated rod-rod poly(2,5-dihexyloxy-p-phenylene)-b-poly(3-butylthiophene) (PPP-P3BT) block copolymers was investigated. A series of monodisperse PPP-P3BT block copolymers synthesized via a sequential Grignard metathesis method (GRIM). Gel permeation chromatographer (GPC), nuclear magnetic resonance (NMR) spectra, differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) was used to characterize the block copolymers. Small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS) patterns as a function of temperature, the detailed phase diagram of the system was then established.
In Chapter 3 of this thesis, we demonstrated a new strategy for fabricating solar cell devices with well-defined double-channel like structure by using an all-conjugated PPP-P3BT block copolymer as an effective structure-directing template for geometrical manipulation of PCBM location. TEM, OM, and GIWAXS measurements were used to explore the detailed structure features and morphological changes of the PPP-P3BT/PCBM sample before and after annealing. Based on the accelerated aging experiments performed on the PPP-b-P3BT/PCBM system, extended thermal annealing was found to lead to slower formation of PCBM aggregations and longer device operational time. As a result, we believe that the use of this novel material provides a feasible way to enhance photovoltaic performance and shows potential for use in future optoeletronic applications.
In Chapter 4 of this thesis, we fabricated organic/inorganic hybrid that contains zinc oxide (ZnO) nanoparticles synthesized in the presence of a novel conducting-conducting diblock copolymer as a structure template for the hybrid system. A simple in-situ synthesis of the self-assembly behavior ZnO/PPP-P3BT nanohybrid systems were investigated. We use zinc acetate dehydrate (Zn(CH3COO)2．2H2O) as a precursor for ZnO nanoparticles and P3BT block as the functional host to chelate zinc ion. The chelated Zn2+ was converted into ZnO by heating in the air at 220 oC. Film samples of ZnO/polymer hybrid were prepared by the following method. First, we prepared a Zn2+/polymers solution, and then drop casted the Zn2+/polymers solution directly onto substrates. Then, the coated substrates were aged at -20oC for 3 days to form the Zn2+/polymers nanowires. Finally, the aged samples were then heated at 220oC for 30 minutes for characterization. The crystallinity and morphology of ZnO nanoparticles/polymer hybrid films were characterized by grazing incidence wide-angle x-ray scattering (GIWAXS) and transmission electron microscope (TEM). From the GIWAXS spectra, the polymer which dissolved in toluene has good orientation and Zn2+ was converted into ZnO (wurtzite crystal structure) by heating in the air. The TEM images also show that the self-aligned ZnO nanoparticles along the PPP-P3BT nanowires were successfully prepared. Thus, these materials may be widely applied in organic electronics.
Subjects
格林納反應
硬桿-硬桿
嵌段共聚高分子
自組裝
PPP-P3BT
PCBM
ZnO
高分子太陽能電池
長效穩定性
SDGs
Type
thesis
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