Emission properties of MEH-PPV in thin films simultaneously illuminated and annealed at different temperatures

• Illumination of MEH-PPV thin films leads to photoluminescence (PL) enhancement.
• High annealing temperatures reduce the enhancement of PL upon illumination.
• After stopping the illumination, the enhanced PL is stable for days.
• Illumination can be used as a processing method for conjugated polymeric materials.

We report on the enhancement of photoluminescence in thin films of poly[2-methoxy-5-((2′-ethylhexyl)oxy)-1,4-phenylenvinylene], neat or embedded in polystyrene, upon illumination with light as a function of annealing temperature, with our data emphasizing the picture of a light-induced conformation change that leads to the altered photophysical response of this polymer.