Recent literature has suggested there is a positive correlation between degree of solution-state aggregation and solid-state morphology and electronic property , and solution aggregated polymers are often found to have significantly improved device performance compared with well-dissolved polymers . One prominent work by Li and Janssen et al. has shown that by varying the solvent quality, an amorphous (α) and a semicrystalline polymorph (β1) of solution aggregates can be tuned into a more ordered phase β2 featured by appearance of an UV-vis absorption peak at longer wavelength . This β2 phase with a reduced π-stacking distance can be inherited into solid-state, exhibiting a higher hole mobility in organic fieldeffect transistors (OFETs) and enhanced photocurrent generation in organic solar cells. Another example of naphthalene diimide based polymer (P(NDI2OD-T2)) has demonstrated that when dissolved in poor solvent like toluene and xylene, P(NDI2OD-T2) exhibited a newly emerged absorption peak at higher wavelength (815 nm) which is absent in a better solvent (e.g. DCB), indicating a stronger aggregating behavior of the polymer . Such enhancement in the extent of aggregation in poor solvent enabled the solid-state long-range order and thus enhanced charge carrier mobilities measured in OFET devices . Other parameters, including solution (dissolution) temperature , solution aging time , solution UV/ultrasonication treatment , backbone regioregularity , side chain chemistry , have been studied as means to induce aggregation as an ordered precursor to improve the molecular ordering of the resultant film.