A thin film preparation technique, that increases the free volume fraction in spin coated polymer thin films resulting in reduced interchain interaction, was discussed. The photoinduced absorption technique was used to measure the polaron yield. The increased interchain separation resulted in the reduction of the polaron yield, leading to a higher value for the measured photoluminescence efficiency. An increase in permittivity was found using impedance spectroscopy, probably due to greater polarizability. A narrowing of the highest occupied molecular orbital band tail on treatment was shown by space charge limited conduction analysis resulting in reduced trapping.