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Conjugated luminescent polymers and oligomers, exhibiting stimulated emission (SE), are dispersed in polymethylmethacrylate (PMMA), films and optical fibers, either by blending or upon copolymerisation. With this PMMA doping, we aim to achieve gain and ultrafast optical switching. The modification of the dopant’s chemical structure allows the tuning of the SE spectral region. Furthermore, we aim to achieve dopant chain isolation while maximising their concentration. In this paper, we present an overview of the research done in this area in the context of the European Union (EU)-funded research project “plastic optical fibers with embedded active polymers for data communications-POLYCOM”. [ABSTRACT FROM AUTHOR]

Here we present the assembly of novel transparent all-polymer distributed feedback (DFB) lasers. Flexible and highly transparent cellulose diacetate (CdA) was employed as substrate on which gratings with different periods were engraved by thermal nanoimprinting with high fidelity. Highly luminescent conjugated polymers (CP), poly (9,9-dioctylfluorene) (PFO), poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), and a blend of F8BT and poly(3-hexylthiophene)-poly(9,9-dioctylfluorene-alt-benzothiadiazole) (P3HT:F8BT) were deposited by spin coating onto the nanostructured plastic surfaces, giving rise to perpendicular single-mode lasing emission in the blue, green, and red wavelength ranges, respectively. These lasers show linewidths below 1 nm and low thresholds (≈6 μJcm−2 for blue and red lasing emission), comparable to other state-of-the-art lasers obtained from similar optical gain materials on rigid substrates. The followed strategy is scalable and versatile, enabling the development of large area nanoimprinted DFB lasers (>1cm2) on plastic, which is highly relevant for applications in various markets. Multi-colored polymer lasers: Highly luminescent polymers can work as lasers when incorporated with suitable cavities and now the nano-imprinting makes the fabrication much cheaper and more scalable. An international team led by Prof Juan Cabanillas-Gonzalez from Madrid Institute for Advanced Studies in Nanoscience, Spain demonstrates transparent all-polymer distributed feedback (DFB) lasers in blue, green, yellow and red. The most important step is to make sub-wavelength periodic gratings on the flexible and highly transparent cellulose diacetate substrates by thermal nano-imprinting with high fidelity to maximize the constructive interference effect. As a result, these lasers show narrow linewidths below 1 nm at low power thresholds of several μJ cm^−2, which is comparable to conventional approaches. This large area nano-imprinting method is scalable and adaptable and it enables stackable multi-colored laser emission. [ABSTRACT FROM AUTHOR]

We report on an organic electroluminescent device with simplified geometry and emission in the red to near infrared (NIR) spectral region which, has the lowest turn-on voltage value, 2.3 V, among light emitting electrochemical cells (LEECs). We have synthesized and characterized three novel ruthenium π-extended phenanthroimidazoles which differ on their N^N ligands. The use of dimethyl electron donating groups along with the π-extended phenanthroimidazole moiety promotes ambipolar transport thereby avoiding the use of additional charge transport layers. Furthermore, a facile cathode deposition method based on transfer of a molten alloy (Ga:In) on top of the active layer is deployed, thus avoiding high vacuum thermal deposition which adds versatile assets to our approach. We combine ambipolar charge transport organic complex design and a simple ambient cathode deposition to achieve a potentially cost effective red to NIR emitting device with outstanding performance, opening new avenues towards the development of simplified light emitting sources through device optimization. [ABSTRACT FROM AUTHOR]

We demonstrated a simple, directly-readable approach for high resolution pH sensing. The method was based on sharp changes in Amplified Spontaneous Emission (ASE) of a Stilbene 420 (ST) laser dye triggered by the pH-dependent absorption of Bromocresol Green (BG). The ASE threshold of BG:ST solution mixtures exhibited a strong dependence on BG absorption, which was drastically changed by the variations of the pH of BG solution. As a result, ASE on-off or off-on was observed with different pH levels achieved by ammonia doping. By changing the concentration of the BG solution and the BG:ST blend ratio, this approach allowed to detect pH changes with a sensitivity down to 0.05 in the 10-11 pH range. [ABSTRACT FROM AUTHOR]