Full organic distributed feedback cavities based on a soluble electroluminescent oligothiophene

We have studied the emission spectra of spin-coated films of a novel soluble substituted quinque-thiophene under nanoseconds pulsed excitation. The photoluminescence spectra show a clear line narrowing, ascribed to amplified spontaneous emission assisted by waveguiding inside the film slab, for excitation energy fluence above 0.8 mJ cm(-2). We employed our oligothiophene as active medium for a fully organic distributed feedback (DFB) resonator on a flexible transparent substrate of poly(dimethylsiloxane) (PDMS). The DFB has been fabricated by replica molding from a master grating realized by electron-beam lithography, and subsequent spin coating of the active material on the patterned side of PDMS. It shows a clear DFB emission at about 603 nm of linewidth 0.8 nm.