Synergistic effects of ultrasonication and the addition of a nucleating agent on improving the crystallization and performance of P3HT

A Simple Method to Tailor the Electrical and Tensile Properties of Poly(3-hexylthiophene) Ultrathin Films

“…The P3HT films used in this work were spin-coated from dilute solutions with concentrations as low as 1.0 mg/mL (c* is 5.3 mg/mL 29 ). The thicknesses of the P3HT5 films were accurately measured by AFM, and the results are summarized in Table 1.…”

“…P3HT5-90-80 indicates the P3HT film with 5.0 wt % HPN-68L that was spin-coated from the P3HT/HPN-68L solution with the solvent ratio Tol/ODCB = 90:10 and ultrasonicated for 80 s. In addition, P3HT0 denotes the P3HT film spin-coated from the Tol solution (1.0 mg/mL) with no nucleating agent and no ultrasonication. The data of the P3HT0 film were used for comparison and were obtained from our previous work …”

“…The data of the P3HT0 film were used for comparison and were obtained from our previous work. 29 F4TCNQ was dissolved in dichloromethane (1.0 mg/mL) and ultrasonicated at room temperature for 10 min for complete dissolution. The F4TCNQ solution was freshly prepared before doping.…”

“…In these two works, although the electrical properties and stretchability of P3HT films, especially the stretchability, were improved by the increase in the number of tie chains due to the addition of HPN-68L in comparison to P3HT films processed under the same conditions (annealing or ultrasonication) but without a nucleating agent, the COS was still slightly lower than that of the original film, namely, we can improve the electrical performance and avoid obvious brittleness of P3AT films but not simultaneously improve both the electrical properties and stretchability. We analyzed the experiments in detail and found that in the P3HT film with a high nucleating agent content (5.0 wt %), large nanofiber structures unexpectedly formed, resulting in both the conductivity and COS deteriorating, especially the COS, which dramatically decreased . The number of tie chains is higher in P3HT with 5.0 wt % HPN-68L than in P3HT with a low HPN-68L content.…”

“…The tie chain fraction (f TC ), crystallinity and order of P3HT increase with the increase in the HPN-68L content. 29 Ultrasonication causes a concentration fluctuation in the dilute P3HT/HPN-68L solution; the longer the ultrasonication time is, the higher the concentrations of P3HT and HPN-68L in the concentrated region and the more uniform the dispersion of the concentrated region in the solution. Gomez et al reported that faster crystallization kinetics of polythiophenes led to more tie chains between crystalline regions and consequently higher charge mobilities in organic field-effect transistors (OFETs).…”