Interfacial analysis of the rrP3HT samples spin-coated on a glass substrate was studied in detail using transmission electron microscopy (TEM) and SEM measurements. Very homogeneous and smooth polymer (P3HT and PEDOT:PSS) layers are observed on the glass substrate. The ITO surface shows a surface roughness, with a layer of about 15 nm. Structural characteristics of the polymer blends were studied using Raman spectroscopy and photoluminescence (PL). Thecomplete reduction of PL of P3HT after mixing with C-60 in a 1: 1 wt% indicates an effective charge transfer from P3HT to C-60. Thermo-gravimetric analysis showed that the commercially bought materials are of high purity.