Kinetics and Mechanism of Poly(3-Hexylthiophene) Crystallization in Solution under Shear-flow

Published

July 28, 2020

Author(s)

Ngoc A. Nguyen, Hao Shen, Yun Liu, Michael E. Mackay

Abstract

The morphology of poly (3-hexylthiophene) (P3HT) in its liquid phase and its manipulation via flow-induced solution crystallization and its crystallization kinetics was studied to determine its mechanism. Shear-flow induced ordering of semi-conducting P3HT, which generates more perfect crystal structures than quiescent methods, is elucidated through using in-situ rheo-SANS and rheo-SALS and an Avrami analysis performed. Characteristic lengths of P3HT crystals were measured as a function of time, and 3-D networks of percolated P3HT fibril crystals were determined by measuring the fractal dimension, 2.6, through fitting rheo-SANS data with a power law function. Additionally, UV-Vis and DSC results revealed a process of P3HT crystal perfection determined by following the evolution of absorption peaks characteristic of pi-pi stacking at 600 nm and the melting peaks as they shifted and narrowed with respect to increasing shear time. The Avrami exponent, m, approached a maximum value of 2 indicating homogeneous nucleation of P3HT macromolecules that allowed 1-dimensional fibril crystal growing and limited by contact time between the P3HT molecules rather than the diffusion of P3HT chains that is attributed by the highly directional pi-pi stacking attractions of electron pi in the thiophene rings.

Citation

Macromolecules

Volume

53

Issue

14

Pub Type

Journals

Download Paper

Local Download

Keywords

solar cell, small angle neutron scattering, Poly (3-hexylthiophene)

Citation

Nguyen, N. , Shen, H. , Liu, Y. and Mackay, M. (2020), Kinetics and Mechanism of Poly(3-Hexylthiophene) Crystallization in Solution under Shear-flow, Macromolecules, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930338 (Accessed May 9, 2025)