Angew. Chem. Int. Ed. http://doi.org/f3tnwf (2016)

Taking inspiration from plant leaves, researchers in the Netherlands have created a photomicroreactor that collects sunlight, converts it to a desired, narrow-wavelength region and then uses it to convert chemical reactants flowing in nearby microchannels. The approach may ultimately prove useful for the manufacture of solar fuels, pharmaceuticals and agrochemicals. The design is realized by implementing a luminescent solar concentrator from fluorescent dye-doped polydimethysiloxane (PDMS), which acts as a light guide with high transparency and good thermal stability. A PDMS platform 50 × 50 × 3 mm3 was fabricated that featured an embedded 150 μl flow microreactor consisting of a serpentine-shaped microchannel (500 μm wide and 1 mm high). The PDMS was doped with the fluorescent lumiphore LR305 (doping concentration of 10–250 ppm) that strongly absorbs light in the 400–600 nm window and re-emits it at around 650 nm. As a benchmark reaction to test the effectiveness of the system, the [4+2] cycloaddition of singlet oxygen to 9,10-diphenylanthracene was monitored using methylene blue as a photocatalyst that has an absorption that overlaps with the LR305 emission. Tests with blue LED illumination, solar simulator and outdoor experiments on a sunny summer day all indicated that the reactor featuring the LR305 dopant exhibited a significant increase in the conversion rates of the reaction when compared with a non-doped reactor.