Switchable 2D-waveguiding abilities of luminescent hybrid nanocomposites for active solar concentrators.

Passing from fossil energy sources to renewable ones, meanwhile answering the increasing world energy demand, will require innovative and low cost technologies. Smart photovoltaic windows could fulfil our needs in this matter. Their transparency can be controlled to manage solar energy, regulate interior temperature and illumination. Here we present the one-pot synthesis of polymer dispersed liquid crystal (PDLC), in which highly red-NIR phosphorescent transition metal clusters are embedded in a controlled manner, either in the polymer, in the liquid crystal or in both phases. The PDLC matrix is used as a tuneable waveguide to transfer the emitted light from nanoclusters to the edge of the device where solar cells could be placed to convert it into electricity. Edge emission is obtained in both "off" and "on" state with a maximum intensity for the scattering "off" one. These doped PDLCs showing photoactivity features and high stability under voltage represent key stepping stones for integration in buildings, displays, and many other technologies.