Upon synthesizing pDPP3T, thin films were fabricated for characterization by spin coating from chlorobenzene solutions at 80 °C. The effect of UVO surface treatment on the semiconductor film properties was investigated by subjecting the films to varied exposure times of 0 s, 1 s, 5 s, 30 s, 60 s, 180 s, 600 s and 1200 s using an Ossila UV-Ozone cleaner. To assess changes to the polymer's optical properties after UVO exposure, UV-Vis-NIR spectroscopy was carried out and the resulting spectra are displayed in Figure . The pristine pDPP3T film exhibited two main absorption features, a π-π* band at 415 nm and the intramolecular charge transfer (ICT) band with λmax at 810 nm. After UVO exposure, a decrease in ICT absorbance relative to the π-π* band was observed, which took greater precedence with increasing UV-Ozone exposure time (visualised in Supplementary Figure ). This in conjunction with blue shifting of π-π*, could indicate the breakdown of the conjugated polymer chains. It was found that beyond t = 600 s, the ICT band diminishes (as shown for t = 1200 s, Figure ) and therefore further study was limited to UVO exposure times ≤ 600 s.