Cocrystallization mechanism of poly(3‐hexyl thiophenes) with different amount of chain regioregularity

Pal, Sourav; Nandi, Arun K.

doi:10.1002/app.24067

Cited by 22 publications

(21 citation statements)

References 70 publications

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“…Hence the observed mechanism for crystallite growth is general for P3EHT and may describe crystallization in other polythiophenes as well. Isothermal crystallization of bulk P3ATs, for instance, was shown by differential scanning calorimetry (DSC) to yield n values well below 2 . P3HT crystallization within bulk heterojunctions also exhibit a diffusion‐controlled growth process with n values ≈1 .…”

Section: Resultsmentioning

confidence: 99%

Mechanism of Crystallization and Implications for Charge Transport in Poly(3‐ethylhexylthiophene) Thin Films

Duong

Shang

et al. 2014

Adv Funct Materials

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In this work, crystallization kinetics and aggregate growth of poly(3‐ethylhexylthiophene) (P3EHT) thin films are studied as a function of film thickness. X‐ray diffraction and optical absorption show that individual aggregates and crystallites grow anisotropically and mostly along only two packing directions: the alkyl stacking and the polymer chain backbone direction. Further, it is also determined that crystallization kinetics is limited by the reorganization of polymer chains and depends strongly on the film thickness and average molecular weight. Time‐dependent, field‐effect hole mobilities in thin films reveal a percolation threshold for both low and high molecular weight P3EHT. Structural analysis reveals that charge percolation requires bridged aggregates separated by a distance of ≈2–3 nm, which is on the order of the polymer persistence length. These results thus highlight the importance of tie molecules and inter‐aggregate distance in supporting charge percolation in semiconducting polymer thin films. The study as a whole also demonstrates that P3EHT is an ideal model system for polythiophenes and should prove to be useful for future investigations into crystallization kinetics.

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Section: Resultsmentioning

confidence: 99%

Mechanism of Crystallization and Implications for Charge Transport in Poly(3‐ethylhexylthiophene) Thin Films

Duong

Shang

et al. 2014

Adv Funct Materials

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“…The performance of devices depends largely on the structure and morphology of polythiophene in the active layer. As a result, it has been the subject of numerous studies how to control the morphology, crystal structure, and crystallization behavior of polythiophene, especially the effect of the electron acceptors, for example, fullerene, on the crystallization behavior of P3HT 3–11…”

Section: Introductionmentioning

confidence: 99%

Nonisothermal crystallization behaviors of poly(3‐hexylthiophene)/reduced graphene oxide nanocomposites

Yang

2012

J of Applied Polymer Sci

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Poly(3-hexylthiophene) (P3HT)/reduced graphene oxide (rGO) nanocomposites were prepared through in situ reduction of graphene oxide in the presence of P3HT. The nonisothermal crystallization behaviors of P3HT and P3HT/rGO nanocomposites were investigated by differential scanning calorimetry. The Avrami, Ozawa, and Mo models were used to analyze the nonisothermal kinetics. The addition of rGO remarkably increased the crystallization peak temperature and crystallinity of P3HT, but the crystallization half-time revealed little variation. The crystallization activation energies were calculated by the Kissinger equation. The results suggested that rGO plays a twofold role in the nonisothermal crystallization of P3HT, that is, rGO promotes the crystallization of P3HT as nucleating agent, and meanwhile, it also restricts the motion of P3HT chains.

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“…Experimentally, precisely controlling the RDOC for CP is not straightforward. In general, the conventional DSC is not capable to quench the CPs to the supercooled, or completely amorphous state owing to the fast crystallization rate of CPs . For example, as shown in Figure S7, the crystallization of P3(2EB)T is inevitable upon cooling it from its melt state with conventional DSC even at 100 K min −1 , while faster cooling speed using flash DSC can trap P3(2EB)T into the fully amorphous phase using a cooling rate of 60,000 K min −1 (1,000 K s −1 ), as shown in Figure subsequently.…”

Section: Resultsmentioning

confidence: 99%

“…In general, the conventional DSC is not capable to quench the CPs to the supercooled, or completely amorphous state owing to the fast crystallization rate of CPs. 15,20,25,38,[58][59][60][61] For example, as shown in Figure S7, the crystallization of P3(2EB)T is inevitable upon cooling it from its melt state with conventional DSC even at 100 K min −1 , while faster cooling speed using flash DSC can trap P3(2EB)T into the fully amorphous phase using a cooling rate of 60,000 K min −1 (1,000 K s −1 ), as shown in Figure 4 subsequently. This trapped amorphous glass can be heated up to its crystallization temperature and vary the isothermal crystallization time to precisely control the degree of crystallinity.…”

Section: Effect Of Crystallinitymentioning

confidence: 99%

Challenge and Solution of Characterizing Glass Transition Temperature for Conjugated Polymers by Differential Scanning Calorimetry

Qian

Galuska

McNutt

et al. 2019

J Polym Sci B Polym Phys

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Thermomechanical properties of polymers highly depend on their glass transition temperature (T g). Differential scanning calorimetry (DSC) is commonly used to measure T g of polymers. However, many conjugated polymers (CPs), especially donor–acceptor CPs (D–A CPs), do not show a clear glass transition when measured by conventional DSC using simple heat and cool scan. In this work, we discuss the origin of the difficulty for measuring T g in such type of polymers. The changes in specific heat capacity (Δc p) at T g were accurately probed for a series of CPs by DSC. The results showed a significant decrease in Δc p from flexible polymer (0.28 J g−1 K−1 for polystyrene) to rigid CPs (10−3 J g−1 K−1 for a naphthalene diimide‐based D–A CP). When a conjugation breaker unit (flexible unit) is added to the D–A CPs, we observed restoration of the Δc p at T g by a factor of 10, confirming that backbone rigidity reduces the Δc p. Additionally, an increase in the crystalline fraction of the CPs further reduces Δc p. We conclude that the difficulties of determining T g for CPs using DSC are mainly due to rigid backbone and semicrystalline nature. We also demonstrate that physical aging can be used on DSC to help locate and confirm the glass transition for D‐A CPs with weak transition signals. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1635–1644

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Cocrystallization mechanism of poly(3‐hexyl thiophenes) with different amount of chain regioregularity

Cited by 22 publications

References 70 publications

Mechanism of Crystallization and Implications for Charge Transport in Poly(3‐ethylhexylthiophene) Thin Films

Mechanism of Crystallization and Implications for Charge Transport in Poly(3‐ethylhexylthiophene) Thin Films

Nonisothermal crystallization behaviors of poly(3‐hexylthiophene)/reduced graphene oxide nanocomposites

Challenge and Solution of Characterizing Glass Transition Temperature for Conjugated Polymers by Differential Scanning Calorimetry

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