Highly-photostable and mechanically flexible all-organic semiconductor lasers

Two formats of all-organic distributed-feedback lasers with improved photostability, respectively called nanocomposite and encapsulated lasers, are reported. These lasers are compatible with mechanically-flexible platforms and were entirely fabricated using soft-lithography and spin-coating techniques. The gain elements in both types of lasers were monodisperse pi-conjugated star-shaped macromolecules (oligofluorene truxene, T3). In the nanocomposites lasers, these elements were incorporated into a transparent polyimide matrix, while in the encapsulated devices a neat layer of T3 was overcoated with Poly(vinyl alcohol) (PVA). The T3-nanocomposite devices demonstrated a 1/e degradation energy dosage up to similar to 27.0 +/- 6.5 J/cm(2) with a threshold fluence of 115 +/- 10 mu J/cm(2). This represents a 3-fold improvement in operation lifetime under ambient conditions compared to the equivalent laser made with neat organic films, albeit with a 1.6-time increase in threshold. The PVA-encapsulated lasers showed the best overall performance: a 40-time improvement in the operation lifetime and crucially no-trade-off on the threshold, with respectively a degradation energy dosage of similar to 280 +/- 20 J/cm(2) and a threshold fluence of 36 +/- 8 mu J/cm(2).