Effect of Regioregularity on Charge Transport and Structural and Excitonic Coherence in Poly(3-hexylthiophene) Nanowires

Abstract

This study explores the role of very small changes in poly­(3-hexylthiophene-2,5-diyl) (P3HT) regioregularity on the physical and electronic properties of P3HT nanowires. Due to a high level of synthetic control, we are able to isolate the effects of regioregularity from those of polymer molecular weight and dispersity for the first time. A series of P3HTs with regioregularities from 96 to 99%, similar molecular weights, and low dispersities are synthesized. The charge transport properties of these polymers, along with a Soxhlet extracted 93% regioregular P3HT purchased from Rieke metals, are investigated in both thin film and nanowire transistors. The resulting structural characteristics are examined by atomic force microscopy and X-ray diffraction, and the optical characteristics are explored by UV–vis absorption. It is found that increasing the P3HT regioregularity results in improved charge transport characteristics, with an increase in mobility by a factor of 4 for the regioregularities examined. The increased mobility is shown to reflect increasing structural coherence lengths in the (010) direction, as well as improved J-aggregate characteristics due to greater planarity and reduced numbers of defect sites along the polymer nanowires. Overall, this study serves to emphasize the importance of determining and reporting even small changes in polymer regioregularity.

Structure and design of polymers for durable, stretchable organic electronics

“…[104][105][106] Changing the RR also provides a strong mechanism by which to adjust the mechanical properties. 107 Specifically, going from a 98% RR P3HT to a 64% RR P3HT decreases the modulus from 287 to 13 MPa, and the maximum elongation from 0.5 to 5.5%, shown in Figure 10.…”

Enhanced miscibility and strain resistance of blended elastomer/π‐conjugated polymer composites through side chain functionalization towards stretchable electronics

“…Insight into the packing structure of P3Br x HT can be extracted from the ratio of the 0–0 and 0–1 peak transitions ( A 0‐0 / A 0‐1 ) and is a key piece for elucidating functionalization effects on the backbone arrangement because a larger ratio is tied to improved electrical performance . All absorbance spectra of the films exhibited the H‐aggregate character with A 0‐0 / A 0‐1 < 1 indicating greater interchain interactions by π–π stacking, whereas J‐aggregate character with A 0‐0 / A 0‐1 > 1 would be attributed to dominant intrachain interactions by planar, long‐range order (Table ) .…”

Organic Solar Cell by Inkjet Printing—An Overview

“…Considering the fact that large area formation and roll-to-roll (R2R) processing can be done by inkjet printing, it can be a good choice for preparing homogeneous and thin layers of active materials for constructing organic solar cell [13]. Inkjet printing permits deposition of active material solutions on definite areas of the substrate which are already beneficiary to incorporate layers onto substrates containing layers of other components, which is an important advantage for the fabrication of OSCs [15][16][17][18][19][20]. In solar cell module, adjacent solar cell blocks are electrically connected in series with each other.…”