Luminescence intensity enhancement induced by laser irradiation in poly(vinyl alcohol) and poly(3-thiopheneacetic acid) blend

Photoluminescence (PL) of polymeric blends with poly(vinyl alcohol) (PVA) and poly(3-thiopheneacetic acid) (PTAA) was investigated. We found an increase in the PL intensity induced by laser irradiation. The PL quantum efficiency was dependent on irradiation time, laser intensity, and PTAA doping state (acid or salt). PL intensity increased up to 200% for acid PTAA and 50% for salt PTAA. The PL efficiency relative enhancement was 314% for acid PTAA and 140% for salt PTAA. Using infrared spectroscopy, we related this effect to hydrogen bond interaction between PTAA and PVA excited states induced by laser irradiation that reduced the non-radiative decay rate.