Increased order and improved hole mobility in MEH-PPV thin films by removing shortest chains

► Prior work indicates charge transport is correlated with homogeneity. ► Entropy considerations indicate mesoscopic homogeneity is inversely correlated to polymer polydispersity (PDI). ► Reducing PDI promotes the capability of crystallization. ► Reducing PDI increases hole mobility. ► Reducing PDI allows non-dispersive transport at lower temperatures.