  Atomic Force Microscopy (AFM) and Grazing Incidence X-Ray Diffraction
(GI-XRD) are used to characterize the nanomorphology of spin-coated low (LMW,
Mn = 12 kg/mol, regioregularity RR = 84%) and high (HMW, Mn = 39 kg/mol, RR =
98%) molecular weight poly(3-hexylselenophene) (P3HS) films and blend films of
P3HS with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), before and after
thermal annealing at 250 {\deg}C.
