In DSSCs, solar light is harvested by an organic or metallorganic dye molecule, anchored on a nano-crystalline thin-film semiconductor through a molecular bridge. One of the crucial aspects of DSSCs is therefore represented by the light harvesting dye, whose most important properties should meet the criteria for high absorption coefficients, long term stability, high yield for interfacial eletron transfer into the semiconductor and relatively slow charge recombination. Organic dyes usually present a D(donor)–π(bridge)–A(acceptor) structure which allows for a rational design of the system and the independent optimization of the different block components. By systematically varying the structure of the different components it is possible to monitor the effect of each part of the dye on electron transfer efficiency. 

Luminescent Solar Concentrators are photonic devices able to harvest solar light and concentrate it on a small surface. They are generally fabricated by dispersing a highly fluorescent dye into a polymer matrix. The light absorbed and emitted from the dye can travel through the matrix by total internal reflection, being concentrated on the small surface areas on the sides of the device.

We have recently studied new dyes based on a quinoxaline core, absorbing light in the 370-550 nm range and presenting emission maxima at 550-600 nm. They are very promising dyes for LSC fabrication, thanks to their excellent quantum yields and large Stokes shifts. When dispersed in PMMA and PCMA matrices they exhibit remarkable internal and external photon efficiencies, even superior to the state of the art dye Lumogen Red 305.

Papucci C., et al, J. Mater. Chem. C, 2021, 9, 15608-15621, DOI: 10.1039/d1tc02923a