Effect of structural modifications in the laser properties of polymer films doped with perylenebisimide derivatives

In this work we study the effect of different types of modifications of the chemical structure of perylenebisimide derivatives (PBIs) in the laser properties of PBI-doped polystyrene films at various concentrations. In particular, we focus on controlling the wavelength of emission, in order to tune the laser wavelength, as well as on increasing the amount of PBI in the films, aiming to decrease the laser thresholds, while keeping a good photostability. Amplified spontaneous emission (ASE) was observed for all compounds, the best performance being obtained for films doped with PBIs symmetrically substituted at the imide positions, that emitted at 580 nm with a threshold of 20 kW/cm2 and a photostability half-life of 30,000 pump pulses. Substitution at the bay positions of the PBI core and replacement of imide functions by anhydride groups allow to red-shift the emission wavelength up to 645 nm, but the thresholds increase considerably and the photostability is reduced. PBIs are among the most photostable materials reported in the literature and show very reasonable thresholds. In addition they have a great potential for their application in the field of data communications based on poly(methyl methacrylate) optical fibers, with low-loss transmission windows between 530 and 590 nm and at 650 nm.