New strategy for enhancing performance of P3HT-based organic field-effect transistor via regulating the precipitated speed of solute in volatile solvents

In this work, a new strategy is proposed to improve the performance of poly (3-hexylthiophene-2,5-diyl) (P3HT) based organic field-effect transistor (OFET). The high orientation of P3HT chain is obtained via utilizing precipitation characteristics of P3HT in volatile CH₂Cl₂ with the temperature decrease of solution in the hot spin-coating process. Meanwhile, a small amount of 1,2-dichlorobenzene (ODCB) with high boiling point is introduced into CH₂Cl₂ to make the inner part of the film stay in liquid state for a long time, and prolong the self-organization time of P3HT chain. Compared with control device prepared in pure CH₂Cl₂, the mobility of optimized device obtained by using blended solvent increases about 20-fold, the on/off ratio enhances about three orders of magnitude, and the operation time window of spin-coating up to 30 min (control device < 30 s). With this new strategy, the film quality can be easily controlled, which provides a new method for preparation of high-performance polymer optoelectronic devices.