Partially polarized fluorescence emitted by MEHPPV in solution

This work reports on the use of the ellipsometry technique to study the polarization state of emitted light by poly[2-methoxy-5-((2′-ethylhexyl)oxy)-1,4-phenylenevinylene] (MEHPPV) in solution. The sample presents a partially linear-polarized fluorescence not affected by molecular-concentration, excitation-laser power, probe-wavelength and cuvette-material. The independence of the polarization degree with these variables and its variation with solvent viscosity suggest that the effect can be understood, assuming the existence of a steady regime where light is absorbed and reemitted faster than the average molecular diffusion time. Moreover, we verified that the polarized emission is also observed by other polymers in solution.